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By May 22, 2012 Read More →

Off Grid Power

electricity_generator

Do you like the idea of reducing if not eliminating your electric bill?  There are ways to do this, but of course the electric companies don’t want you to know because then it digs into their pockets.  There are multiple ways to generate electric without having to fully rely upon some multi-billion dollar company to do this for you, so let’s talk about them.

There are different types of power generators that you can purchase or make yourself.  They all pretty much have the same purpose which is to power up something or all things in our home or business.  Gas/diesel, wood, or wind are all ways that produce electricity.

So, now that we know that, we can do a little research into Power Generators.  When I think of any type of generator, and there are many, I automatically think of money.  The first thought being, how much is this going to cost me?  The second thought is, how much will this save me?  Ultimately though, a generator is well worth it, should there be a power outage or if you want to go completely off grid for a while, but do not want the absence of electricity.  Power generators, like food storage/preservation, also allow us to have a sense of security knowing that if the power is out, we don’t have to be.

The first step you should take, when choosing a generator, is deciding what kind you need to power your home and what its purpose will be.  Knowing this is crucial, in your decision making process.

Home Generators: home standby generator

Do you want one that will power your refrigerator, air/heat, water heater and lights?  This type of generator is known as a Home Generator and comes in 4 basic sizes ranging from 22-48 kilowatts.  To determine which size you need, you need to find out how much electricity your house consumes.  These types of generators are very pricy.  The average starting at about $8,000, and go to $15,000 or higher.  Most of these are powered with natural gas and are not intended to be used as a prime source generator for your home.  However, many people with cabins or off grid homes will use these verses paying $50,000 to have electrical lines run to their home.

portable generator

Portable Generator: (PG)

These are typically powered with gas or fuel of some sort. They are exactly what they are called, portable.  I have found they usually come in 4 different sizes, small, medium, large, and extra-large.

A small size PG usually cost about $200 – $300 and will power up an essential appliance in the event of a power outage such as your refrigerator.  Generally speaking, they will run about 9-10 hours per gallon of gas at half load.

A medium size PG runs between $400 – $4,000 depending on the brands and functionality of the one you choose.  These can run on L.P. Gas, (Liquified Petroleum) natural gas, or gasoline.  Some only function on regular gas.  These can provide electricity for things such as light, heat, water heaters, etc.

A large size PG start at $700 and go up from there.  Most run on gasoline and will power things like, electric stoves, water heaters, lights, air/heat, and refrigerators.  Well worth it if you don’t want to be inconvenienced at all.

An Extra Large PG starts at $2000 and up.  Now my first thought here is, who would need that?  The large size seems to do all the basics for comfort right?  Then I read this and now I understand,

“Most homes in Hurricane country are powered entirely by electricity — no natural gas or propane fuel source.  Standby generators simply don’t work in these situations because they need natural gas or propane to generate electricity.
Many homeowners would like a standby generator, but they don’t want to install an unsightly propane tank in their back yard. Their only option is a portable gasoline-powered generator with a big gas tank.
The Generac GP17500E – 17,500 watt generator is the preferred choice because it’s the largest portable generator available, generating enough juice to run a 5-ton air conditioner and a bunch more appliances.” ~ Jim Baugher, Product Expert of Electric Generators Direct

While an extra-large generator is technically portable, they are also very heavy at approx 400 pounds.  So you would want to put this some place you want it to stay.towable generatorMy research shows that the majority of these have automatic engine shut down should it run low on oil, so make sure and keep some oil and gas on hand :)

Towable Generators: 

Now we are talking about some major bucks!!  It’s enough to buy a new car!  The smallest size being medium and starting at around $18,000 and the largest at approx $54,000. Big time moola here.  From what I can tell, these tow-able generators use diesel fuel and are not for your average home or person.  These are used mainly as a source of power at construction sights, oil fields, banks, and smaller commercial places that take top priority in an outage.  According to my source, they are also not the best on fuel and consume more than others due to the high uses of electricity.

wind powerWind Power:

I am sure you have all seen those big white things in fields that look like fans.  These are a form of energy stored to produce electricity created by wind.  At Breeze High wind Generator you can purchase kits for these for $800.  These seem relatively simple to put together, but do require some professional installment.  The unit actually bolts onto the pole so there would be no welding required.

Water Wheel Electricity: waterwheel

Isn’t that picture awesome?  I love the looks of a water wheel.  A lot of people have these just for looks, but some use them for power as well.  I have to be honest, I do not understand exactly how these work, but I have found a site that has a wonderful explanation as to this wonderful wheel.  A man named Spencer Boyd designs and installs these water wheels for a living.  After speaking with him, I have come to the conclusion that these probably are not the best source of energy unless you live near huge bodies of water.  I will explain.  To power an average American home, you would need to install a 12′ Water wheel which uses 3000 gallons of water per minute to run.  Spencer also only recommends that you only install these if you live near a large body of water.  If you wanted a 6′ wheel that would use approximately 400 gallons of water per minute.   Both of these would generate some power, but not enough to be comfortable in the ways we are used to living.  I asked him about running it temporarily in a power outage situation, and he explained that you can hook it up to the generator for such needs, and unhook it when you don’t want to create power.  I would strongly advise you all to visit his site to learn more about this sort of power.  They are also not that expensive and beautiful to look at.  As far as pricing goes, you will have to ask based on your needs and what you want to do.  Me personally, I want one in my yard just for the beauty of it. :)

solar3Solar power:

The ever faithful, solar power.  But what if the sun goes out? I’m just kidding LOL.  People have relied upon the sun for power for many, many years and there are sooo many possible ways to use solar power.  Solar panels are commonly used to generate power in the homes and reduce electricity bills.  Depending on the size and style you have installed, they can run washing machines, electric stoves, lights, run dishwashers and all without using on-grid power sources.  There are many options and styles that will reduce or even eliminate a power bill.  With solar panels, you don’t have to worry about power outages in storms or other disasters.  The price for solar panels and installation varies.  Again, the package you choose would be based on your home usage of energy to decide what you would need.  It can be rather expensive, but like many other sources, in the long run it is well worth it.

Well folks, I hope this gets you interested in generators and different types of off-the-grid power.  I know it has me.  We will be looking into a few of these sources for our home soon.  AS always, feel free to leave comments or suggestions for all of us to learn from. Your input is always welcome. :)

Keepin It Spicy,

Jalapeño Gal

Please Visit my store: Jalapeño Gal’s Survival Surplus

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Cari is an editor and author for American Preppers Network. Her family currently live in Georgia. Cari spends her free time gardening, canning, testing products for review, helping others prepare and going to the gym. She believes preparedness is about love and taking care of your family. Cari also has her own website where she shares all of her preparedness articles and her recipes for canning, dehydrating, juicing, basic cooking. To have a look and hopefully follow her: Click Here! Please Join My New Blog!

57 Comments on "Off Grid Power"

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  1. Bob LaFrank says:

    I wouldn’t consider a petro fired generator as being off grid – Unless of course you have a natural gas source on your property. I am blessed – I have solar, wind and hydro oportunities on my compound

    • Thank you for your opinion bob. :) I feel that anything not requiring the electric company to give us energy could be considered off grid when it comes to power. I am with you however, i would love to have solar power. :)

      JG

  2. Generators are nice to have but I’ve never been a big fan because they are destined to stop working in short order unless a well-stocked fuel supply is on hand. Of course, it’s better to have something on hand than nothing but I think I would first learn to life with as little technology as possible and then work your way up.

  3. I’ve personally not got a lot of experience with generators. I did a lot of research and asked a few friends about them. Maybe I can get the company to let me test some hehehe. I doubt that but its wishful thinking. My aim is for solar panels. I would love to get my house running off solar energy. Any thoughts about that millennumfly?

    • Bob says:

      The problem with solar is it generates a small amount of power for the entire day, which doesn’t serve spike use or supply power at night. As such, you need a battery / Inverter setup that will cost you 4K to 20K and beyond. (And the 4K option is you’re the electrician / engineer and your system is weak.)

      The advantage of generators is they’re relatively cheap (a thousand dollar generator will produce the 220V for the well and the split voltage 110V for everything else.) and it’s really easy to hook up to the Load Center in your house. The disadvantage, of course, is the requirement for fuel. A thousand dollar generator will produce the power of a 10 thousand dollar solar system. But it will require fuel.

      For me, my short term strategy is to have a generator and a supply of fuel. They’re ready to go right now. Long term, I plan on adding batteries and an inverter. (So I can run the generator for a few hours, then run on batteries all night.) and eventually add Solar Panels so I can charge the batteries during the day.

      Like milleniumfly, I’m not a big fan of the generator’s need for fuel.

      • tyler says:

        this is what I am trying to do . I have free gas and a small cabin and I don’t know what size generator to go with.need help

  4. Awesome info guys. I wish I had spoken with you BEFORE I wrote the article. You guys are great. now I am considering both forms of power for our home. :)

    JG

  5. Bob says:

    JG,

    Another important consideration is that all the natural options: I.E. Solar, Wind, Water, etc. have fairly simple and low cost power generators. A solar panel can be had for a few hundred dollars, that windmill you mention is about 800.

    But you can’t use that power directly. It needs to be stored in batteries and then run through an inverter to generate the AC power for your home to use. That’s where all the cost is. These systems range from a few hundred dollars (Basically a car battery connected to a low cost inverter.) to banks of deep cycle batteries driving large inverters connected to the house’s electrical system. Those systems range from 4K (DIY price for about a 5K watt system) to 20K or more.

    Even if you switched to all DC appliances (Or only used it to power a few carefully selected ones, like a Refrigerator and Freezer.) you still need the batteries to store the power, then some kind of regulator to produce the stable voltage (AC or DC, whatever is used.) for the appliances.

    Also, while solar panels are essentially solid state and can last 30 years, batteries do not and need to be replaced about every 7 to 10 years, assuming they’re maintained properly and not abused.

    All things considered, a gas powered generator is a really good starting point. Even if you eventually build a full blown Solar Power Station for your house, you’ll still have the generator for emergency backup.

  6. Bob says:

    Your post got me thinking more about being off grid (Or at least able to survive protracted periods without it.)

    It always comes down to the batteries. You have to store a LOT of juice to run the average home. To know how many batteries you need, you need to know exactly how much you use. There are monitoring systems you can buy and attach to your Load Center, or a plug in device with a monitored outlet called a “Kill-a-Watt”, or you can measure the current directly with a clip on current meter. An easy way to get a fast estimate of this is to look at your power bill. It probably has a history with averages.

    My house (Which is small.) currently uses about 30KWH a day. Doing the math, and assuming I need to run the house at least 2 days without charging (Rainy days, etc.) and without letting the batteries get under 50% charged… I would need 64 deep cycle batteries. Each battery is 6V and has 370AH capacity, that’s pretty much the standard battery for this application. Cost? 240 dollars per, so that’s 15,360 dollars for batteries alone! If I tried to amortize the cost by disconnecting from the grid… I would be greatly reducing their life spans by constantly discharging and recharging them. So… replacing 64 batteries every 4 years (16 per year.) is 3,840 dollars per year. Which is far more than I pay for electricity now.

    That’s just insane. Where would I even store these batteries? No, before switching to off-grid, you have to pare your usage of electricity to the bone. If propane is an option, that can be used to cook and heat water. There is also the solar hot water heater.

    My biggest concern is the refrigerator and freezer. I need those to store food, as I don’t want to rely on the stores always being stocked, etc.

    Long story short, the theoretical minimum power usage for my house is then about 7.2 KWH per day. Even with that minimal use, I would need 8 of the batteries. Using that as a grid backup, battery replacement drops to 1 per year, which is much more manageable. In no case is going “off grid” actually cheaper than using the grid unless you’re willing to almost completely eliminate electricity from your life. But since I’m concerned more about grid availability in the event of crisis, having a working backup capable of going weeks at a time is what I’m looking for.

    • Ted says:

      Bob,
      Good points.  Let me add to the discussion.  
      An important consideration is the noise of a generator and the attention it will attract when you don’t want others to know about your resources.
      Also, in the northwest, solar panels work some, but are not very efficient; ie. takes a lot of them to charge a battery bank.  
      I like and have used propane generators, but getting more fuel in a grid down situation will be difficult.
      Ted

    • Bob says:

      Ted,

      Yeah. The noise is a serious concern. You know how it is… “The first rule of prep club is you don’t talk about prep club.” Nothing broadcasts the fact that you have a generator a week into a grid down situation than running the thing. It’s awfully quiet out there when the grid is down.

      I actually have a plan. I’m speccing the batteries to last a few days before needing to be charged, then I can run the generator to charge them in off hours, like the morning. If anyone asks, I was running something else. That avoids totally suspicious behavior, like running a generator every night.

      I would think propane would be the desired fuel in these scenarios simply because you can store a LOT of it right there on your property without really having to worry. Just be careful and keep it full enough to get through a reasonable grid down period.

      Of course, if the grid is down long enough… all bets will be off. People will probably go around looking for propane to steal. Hopefully that will never happen.

  7. Truth be told, all i really care about getting power to is my deep freeze and my refrigerator. Everything else i can manage without. Not to many people WANT to live without the others but washing and drying clothes can be done manually with a bucket and an old time wash board, or even a barrel fashioned into a washing machine. Ok ok, MAYBE my stove to, but i have learned many alternative ways of cooking as well, something is suggest people do for sure. You have offered so much useful information on the subject bob, I’m very impressed. :) Thank you for your knowledge.

    • Bob says:

      Yeah, I don’t want to do without all that ‘stuff’, like the Washing Machine or the Air Conditioner… but all that ancillary stuff drives the daily power usage into the stratosphere. My estimate of 7.2 KWH is little more than the freezer / fridge require. And the Inverter / battery solution for that still costs 4,000 dollars as a DIY project. Note that I’m speccing quality parts here, not mickey mouse parts that won’t last.)

      And I would still need to fire up the generator once in a while to fill up the water tank from the well. (My well is deep, has a 230V submersible pump.)

      Where you see lower cost estimates is in what’s called a “Grid-Tie” system, where you use the power grid to buffer the power from the solar panels so there are no batteries in your system. But that only works when the grid is up. That’s kind of pointless from my point of view. If the grid was guaranteed to be up, this would be a non issue.

  8. bjoyful says:

    I appreciate the information you offered here but I get confused when I try to implement it. I contacted several solar companies about installing solar power at my home…all insisted that I would then be part of the power grid and could not be off grid. In fact, they informed me that the power grid has to be on for at least 5 minutes before the solar panels would power up. When I requested information in order to be off grid they told me that it’s not possible and I just needed to “get over it”. Help! What’s the point of spending tens of thousands of dollars if nothing runs when the grid is down Any ideas of where to turn for better information?

    We already have a home generator and wind power in my area is cost prohibitive.

    • Its my understanding that you would have to have some sort of battery back up, which doesn’t make much sense to me either. You think solar power means powered by the sun.Bob said…

      “Another important consideration is that all the natural options: I.E. Solar, Wind, Water, etc. have fairly simple and low cost power generators. A solar panel can be had for a few hundred dollars, that windmill you mention is about 800.

      But you can’t use that power directly. It needs to be stored in batteries and then run through an inverter to generate the AC power for your home to use. That’s where all the cost is. These systems range from a few hundred dollars (Basically a car battery connected to a low cost inverter.) to banks of deep cycle batteries driving large inverters connected to the house’s electrical system.

      Even if you switched to all DC appliances (Or only used it to power a few carefully selected ones, like a Refrigerator and Freezer.) you still need the batteries to store the power, then some kind of regulator to produce the stable voltage (AC or DC, whatever is used.) for the appliances.

      Also, while solar panels are essentially solid state and can last 30 years, batteries do not and need to be replaced about every 7 to 10 years, assuming they’re maintained properly and not abused”

      He also stated….

      “The problem with solar is it generates a small amount of power for the entire day, which doesn’t serve spike use or supply power at night. As such, you need a battery / Inverter setup that will cost you 4K to 20K and beyond. (And the 4K option is you’re the electrician / engineer and your system is weak.)

      The advantage of generators is they’re relatively cheap (a thousand dollar generator will produce the 220V for the well and the split voltage 110V for everything else.) and it’s really easy to hook up to the Load Center in your house. The disadvantage, of course, is the requirement for fuel. A thousand dollar generator will produce the power of a 10 thousand dollar solar system. But it will require fuel.”

      I hope this helps some.
      JG

    • alta chica del sol says:

      A thousand dollar generator will not produce the same power as a $10,000 solar power system, if the $10,000 solar power system is designed properly.

      A diesel generator capable of producing the same power as a well-designed $10,000 system would set you back about $5,000. Gasoline generators are a joke. They don’t last long and can’t start heavy loads. If you’re in a prolonged emergency situation, you will need to be able to run power tools, and that means a high-quality diesel generator. Learn how to make biodiesel while you’re at it.

    • Bob says:

      alta chica del sol;

      “A thousand dollar generator will not produce the same power as a $10,000 solar power system, if the $10,000 solar power system is designed properly.”

      I would love to see the math on that. I would love to be wrong, simply because I’d like nothing more than to spend less money on stuff.

      My 800 dollar Generac runs on gas, and while it’s ‘rated’ for 6.5KW (8KW peak), it’s realistically capable of about 4KW of constant output because of the inductive load of starting stuff. Obviously, I would be a fool to think it could run 24/7 for years… for that I would need a solid diesel one. And even then a healthy maintenance budget.

      If you could point me to parts (Inverters, batteries, solar panels, etc.) that can beat that for less than 10K, I’ll be impressed. Heck, I’ll probably buy them.

      I’ll even let you spec the parts using the assumption that the generator will only have to run for 6 hours a day to fully recharge the batteries from a 50% DOD. Please educate me here, I would like nothing more than for my math to be totally wrong on this. Heh… I accept that I’m not Tony Stark, my math isn’t always right!

    • alta chica del sol says:

      Bob,

      An $800 Generac will wear out long before that $10K solar system.

      And while your $800 Generac might be able to make something it claims to be 8kW peak, my pair of $1,800 inverters can start a residential A/C unit, and run the lights, and much of the rest of the house loads, all at the same time.

      There’s well-designed and there’s cheap. I do “well-designed”.

    • Bob says:

      alta chica del sol,

      We’re on the same page here, I fully agree that my Generac will die in short order if I require it to run my house 24/7. It just can’t do it over the long haul. But it also only costs 800 bucks and was really easy to connect to the Load Center. Obviously, this is not a solution long term.

      A pair of 1,800 dollar inverters? Now you’re talking! That sounds like a pair of Outback Power VXF3648 units connected master / slave style so it can produce 230V single phase as well as both legs of 115V for the house. With a total wattage of 7.2KW those deliver everything the Generac can do. They’ll also last a lot longer. Ok, there’s 3,600 bucks. You also need a small army of breakers and panel parts… there’s another 500 dollars per inverter.

      Then you need batteries. Deep Cycle batteries. A lot of them. Like… 16 of the UL-16 type. The inverters, it’s associated panel parts, and the batteries alone put you at the 8K mark. Add in a few solar panels and you have a 10K system that can produce the same power output as a 1,000 dollar generator. I didn’t make that number up… I specced parts and did the math.

      Now let’s look at the drawbacks of that system. 16 UL-16 batteries can store a total of 35.5KWH of power when discharged over 20 hours. (370 Ah at 6 volts per) But if you do that to them they’ll only last 6 months. A reasonable load would be a quarter of that, 8KWH (I rounded down.) spread out over a day. That’s not much power, considering the average house uses nearly 3 times that. So you’ll have to go into major power conservation mode just to make the power last all day, that means no AC, using gas for any appliance that can use it, etc.

      The Generac, on the other hand, produces it’s power for as long as it’s on, producing the same 8KWH the solar system can produce for the whole day every 2 hours. And only running it 2 hours a day will extend it’s life considerably.

      So a 1,000 dollar generator running 2 hours a day produces the same output as a 10,000 dollar solar system.

      Which is better? Oh! The solar! Hands down! Not only will it run the critical appliances like refrigerators and freezers 24 hours a day like they need to be run, but messing with that generator every day and then having absolutely no power when it’s off would suck.

      Even so… you still want that generator as well. Stormy weather for days on end? Fire up the generator to charge the batteries so they never go below that 50% DOD point.

  9. Bob says:

    bjoyful,

    I’ll explain the difference between a “Grid-Tie” system, which is what the people you called sell, and an “Off Grid” system, which is what we as preppers want. Certainly, if your goal is to be able to operate “Off the grid” as we all do, then installing a “Grid-Tie” system that forced you to be connected to the grid makes no sense.

    The primary difference between the two is the batteries. A Grid-Tie system has no batteries. the grid itself is used as the “storage battery” by powering other people’s houses. All power fed back to the grid by you is purchased by the power company from you. Your power meter actually “runs backwards” when your solar panels are making more power than you are currently using.

    Both systems need an inverter to convert the DC power (From the solar panels or the batteries.) to AC power for your home. The Inverter for the Grid-Tie system also synchronizes the AC to the grid, and won’t turn on unless the grid is available. It’s actually very dangerous for utility workers to have an active system feeding AC to the grid when they don’t expect it.

    The off grid system has batteries that are charged when a charge source is available. (The grid, solar panels, wind turbines, a generator, etc.) the batteries then supply the Inverter with the DC power it needs to power your house.

  10. Bruce Hesher says:

    It is fairly easy to make a solar generator that does not require any fuel that needs to be purchased or stored. The up front cost is higher than a gas generator but pays back quickly if you use it much. A solar generator is basically a small stand alone PV systems inteneded to power only your critical needs (refrgerator, aquarium, deep freezer). It can be sclaed up or down to meet your needs.

  11. alta chica del sol says:

    All liquid fuels, gasoline and diesel, have shelf lives and can become completely worthless. Gasoline will turn to varnish and diesel will accumulate paraffin and other wax-like particles.

    If you must have a generator, I’d suggest you look into wood gasification. It was used throughout Europe during WWII and works very well. There will still be trees, use what will be there, not what you are most familiar with.

    Bob’s comments about the difference between grid-tied and off-grid systems are mostly correct. There are hybrid systems that will sell to the grid, and run off-grid from batteries. In a prolonged grid-down situation, you will want to be able to run from DC power since that is much more efficient than having a DC-to-AC inverter producing power, just so most of your appliances can convert it right back to DC power.

    If you are building a bug-out place, do not use 120 volt appliances unless you absolutely most. There are 12 volt DC versions of many appliances. Get those instead.

    • Bob says:

      “All liquid fuels, gasoline and diesel, have shelf lives”

      True. Diesel lasts longer than gasoline, but gasoline can be treated with “Sta-Bil” to stabilize it. You can expect either diesel or stabilized gasoline to last a year in storage. As such, you need a storage strategy just as you do with your foodstuffs. Me? Like most people that live in the woods, I have a small army of gasoline powered tools as well as diesel powered vehicles. This lets me use the “oldest gas” first so it remains usable.

      “I’d suggest you look into wood gasification.”

      Wow. The effort involved in that would be intense. You don’t just load a tree into a gasification reactor. You have to first chop down the tree (Gas powered chainsaw.) Transport the tree to the saw (Tractor driven logging sled.) Render the tree into chipable strips (Gas powered saw mill.) and then chip the strips into gasification ready bits (Tractor driven wood chipper.) Unlike most people, I actually have all that stuff. But even then… you would have to build a gasification reactor and modify a generator to use the really dirty version of natural gas it produces to run. I don’t even want to contemplate the level of planetary emergency that would make me want to do that. My God, it would be “The Road” level stuff.

      “There are 12 volt DC versions of many appliances. Get those instead.”

      This is true, but the 12 volt versions aren’t the holy grail of efficiency you might think. Mostly, they get their efficiency by just being small and weak. I’ll use refrigerators (and by extension, freezers.) as an example.12 volt refrigerators and freezers are tiny… generally less than 2 cubic feet (As opposed to the normal household fridge, which is 19 to 25 cubic feet.) They’re also specced to run off a car’s cigarette lighter plug, which limits the total power to the appliance to about 160 watts. What that means is a 120V powered appliance of the same size has about 8 times more power to work with, so it’s compressor system only has to run a fraction of the time to maintain the temperature inside the refrigerator or freezer. So yes, if you have a weak solar system, using 12V appliances (And accepting the limitations.) will maximize your energy usage. But it’s not a magic bullet of any kind. The biggest 12V freezer I could find had a capacity of only 84 quarts.. (Quarts? Really? Why not Cubic Feet, like the REAL FREEZERS are measured in?) Oh… because a quart is only 1/30th of a cubic foot. So that 84 quart freezer is only about 2.8 cubic feet. Will that feed your family?

    • alta chica del sol says:

      Bob,

      Wood gasification is no where near as difficult as you make it out to be, and because it produces energy, it can be used as the energy source for all those tools. Additionally, it is a source of heat, which can be used for domestic heat as well as hot water.

      I’m most familiar with off-grid solar power, so I have no plans to make use of wood gasification, but I would consider adding wood gas power generation if I were looking for a backup energy source.

    • Bob says:

      alta chica del sol,

      “Wood gasification is no where near as difficult as you make it out to be,”

      Yes it is. You have to cut down trees, drag them to a central location, then grind them into the chips you need to fuel the reactor. How do you plan on doing that without considerable effort and equipment?

      “it can be used as the energy source for all those tools.”

      No it can’t. How can you expect anyone to modify all those pieces of equipment to run on gasified wood? It can’t be stored… you have to generate it on the fly. That means constructing a reactor system on every piece of equipment. Good luck with that.

      But even that is not what I’m interested in:

      “I’m most familiar with off-grid solar power”

      Awesome! I want to hear about the batteries. Are my analyses accurate? Was my dissertation on the 1K cost for a generator as comparable to a 10K Solar system as defined accurate? Tell me about the batteries!

    • alta chica del sol says:

      Bob,

      I think I’m going to pass on answering your questions.

      Wood gasification was used extensively during WWII, as well as both before and after. It’s a tried and true technology that’s renewable and sustainable.

    • alta chica del sol says:

      For anyone who is actually interested in wood gasification, a 3kg piece of well-dried wood is about 1kWh of energy. In an off-grid home, that’s about 1/10 of that you’d need — probably 30 to 40kg per day — and you’d be in great shape.

      You’d need more than 10kWh per day if you want a large residential A/C unit (around 36kWh per day …) or you want to play lots of computer games (about 2kWh per day for a high performance gaming computer), but if you expect to be busy maintaining what you have and protecting yourself and your family, 10kWh per day is probably plenty.

      I have a cousin who’s a professional arborist, so I know what a “tree” weighs. A single nice sized tree can be anywhere from 20 to 40 thousand kilograms. A cord or two of wood (4′ high by 8′ wide by 4′ deep — 128 cubic feet) should be enough for quite a while.

      The great thing about going to a “wood as fuel” based personal energy economy is that wood can provide heat for cooking, hot water, plain old heat, and electricity. There’s not actually anything keeping you from compressing and storing wood gas. The primary fuel gases are H2 (hydrogen) and CO (carbon monoxide). Building hydrogen-tight storage tanks can be hard, but it can be done and I have clients who have compressed hydrogen storage attached to their solar power systems. CO is a much larger molecule, so if something is hydrogen tight, it will also store CO.

    • Bob says:

      Wait, you can get 1KWH of energy from 3kg of wood?

      I stand corrected. My math was totally wrong on that. I thought it was orders of magnitude lower. I thought you needed a super rich source like dried horse manure to get that kind of output.

      Your arborist cousin is right, trees are heavy. And they grow by the literal ton in the forest. Obviously, you have to plan ahead… the wood needs to be downed and chipped ahead of time so it can dry properly, but at 1KWH per 3kg, that’s only 60 to 80 pounds of wood a day. That’s doable in an hour with the right equipment. Equipment I already have. a 50 pound sack of wood chips could fetch a good price on the barter market in the worst case scenario if you can also provide the reactor.

      This new info is a game changer, thank you. I still want to know more about the batteries, though. I apologize if I seemed gruff, it’s just frustrating to find good info on the batteries. They are a huge investment, and yet… they are treated like the 800 pound gorilla in the room.

    • alta chica del sol says:

      Bob,

      I’m not sure what to tell you about batteries on a forum like this. Too many people think they can learn solar power through postings to a forum. You can’t. Find a professional solar installer in your area and hire them.

      For gasifiers, I’d suggest you contact Victory Gasworks.

    • Bob says:

      alta chica del sol,

      I checked out that site. That gasifier is a thing of beauty! They even have “turnkey” solar systems using almost the exact Inverter I mentioned above. I don’t like having to ‘register’ my email address to get a brochure, but at least that’s all the info they want.

      Yikes! That monster costs as much as a luxury car!

      Hmm. I’m not getting e-mailed the brochure for the turnkey solar system. Ah well, I know those inverters cost 1,800 dollars, the 8 200 Ah AGM batteries are about 250 each, and the 15 solar panels are about 350 each. So that comes to around 10K. I have no idea what they’re charging.

      I think the batteries are a typo. It says “(8) 48 Volt 200 amp hour maintenance free AGM batteries” There’s no way those are 48 volt batteries. From what I know about AGM batteries, those are 6 volt batteries that you connect in series to form one 48 volt bank for the inverter (Which needs 48 volts.) I can’t really tell from the picture, but those are probably UPG UP-GC2 batteries. Heck, the picture LOOKS like a UB12550, but that would be a joke… picturing 55 Ah batteries for this application. That doesn’t instill a lot of confidence in me.

      In my opinion, 200 Ah of batteries at 48 volts isn’t enough. By my math, that only nets you a little over 2 kWh to play with a day (Assuming a max of 50% DOD with a 2 day discharge.) You need at least twice that, even with this minimal system. That means stepping up to the L-16 style of AGM batteries, with 390 Ah at 6 volts. (Staying with the maintenance free aspect of the turnkey product,) But a bank of 8 of those would set you back 3,700 dollars.

      For me, I would double the batteries, half the solar panels, and use a dual inverter capable of generating 240V like the MagnaSine MS-4448PAE / 240. I like the Outback Power Inverters, but I have a deep well that must have 240V to run, and I don’t want to have to have 2 separate inverters.

      For batteries, my choice would be the flooded version of the L-16, because of the much lower cost. I don’t have a problem with the maintenance aspect.

    • alta chica del sol says:

      Bob,

      This is why you should hire a competent solar installer, instead of just guessing. Because you’re just guessing.

    • Bob says:

      alta chica del sol,

      “This is why you should hire a competent solar installer, instead of just guessing. Because you’re just guessing.”

      No I’m not. I’m comparing the posted specs against what exists in the real world and making informed comparisons.

      Look, right here in the FAQ for the 3kw Turn-key Home Solar Power System:

      How long will the battery pack last with no input from the sun?
      It depends on how deeply you want to cycle (drain) the battery. It will supply one kilowatt steady for 4 hours.
      60% remaining charge.

      So it will provide 4 kWh before the batteries are at 60% capacity. That’s way too low. The point of having an expensive backup system is so that it can at least run the crucial systems without having to resort to 12 volt RV appliances that no one would be happy with.

      It does that by having 8 AGM batteries producing a total of 200 Ah at 48 volts using batteries supplied by UPG. There aren’t that many different ways to do that. The fact that the batteries in the picture are 55Ah 12 volt ones, the kind they put in those wimpy “Solar Generators” isn’t helping.

      It then goes on to utterly ignore the battery replacement cost in it’s “savings” estimations. These are the experts I’m supposed to listen to?

      But hey, I’m just guessing, right? If you could explain to me how it is that “I’m just guessing.” I’d appreciate the information. So… let’s say I hire this “Competent Solar Installer” without understanding what he or she is telling me? How could I tell the difference between what I need and what they want to sell me? I couldn’t, could I? And since I wouldn’t know the system won’t work right until there’s an extended power outage, I’ll be out of luck.

    • alta chica del sol says:

      Bob,

      A man climbs a mountain to see a Zen Master that he had heard much about. When he gets to the top of the mountain, he greets the Master and tells him the purpose of his journey. He wants to learn the secrets of Life, the Universe and Everything.

      The Zen Master offers him a cup of tea while the talk. As the Zen Master prepares the tea, the man start talking about tea, and Zen, and everything else.

      The Zen Master finishes making the tea and walks over to the man, who is eagerly holding out his cup. The Master pours the tea until the cup over flows. At first the man is surprised. Then he starts to complain: “Hey, what are you? Blind or something? There’s tea pouring all over the floor! You don’t even know how to pour a cup of tea! Why am I even here?!?”

      The Zen Master responds, “If you wish to learn the meaning of Life, the Universe and Everything, you must first empty your mind.”

      You obviously know everything there is to know about solar power. I can’t help you. I’m sorry.

    • Bob says:

      I wish that were true, I most certainly do not know all there is to know about this. What I DO know is that I want neither of the solutions offered by the industry.

      Here’s my take on the solar industry: There are two kinds of system design… Grid tie and off grid. The two are totally different in their design philosophy. Everything I read focuses almost completely on either of these philosophies. There is almost no crossover. And when there IS crossover, it’s 95% Grid tie, 5% Off grid. Usually a weak back up scheme. (Like that system on Victory’s site.)

      The two philosophies are:

      Grid Tie: The grid is god. The purpose of solar is to lower carbon footprint by group sourcing the generation of power through the grid. As a bonus, the government will give you a tax write off. This philosophy assumes the grid is up >99% of the time.

      Off Grid: The grid is dead. This philosophy assumes there is no grid available to use at the installation location. This design philosophy focuses on the batteries, and tries to build a system that holds power availability over 90% at all times.The other 10% is handled by a generator of some kind. This results in systems with either enormous battery and maintenance costs, or minimalistic “In the woods with a light bulb and a laptop” low cost systems.

      I don’t want EITHER of these solutions. I WANT to use the grid when it’s available. Currently, that’s over 99% of the time. I don’t really care about “selling” power back to the grid… it’s not expensive enough to warrant that. Why would I install a system that takes 15+ years to pay for itself where I assume ALL the risk? I’ll just use the grid! What I WANT, is a hedge against grid failure. A system or group of systems that step in and provide power when the grid fails.

      As a prepper, I’m concerned that the grid won’t have >99% up time at some point in the future. For this, I need to construct a layered strategy using the available technologies to supply power as needed for when the grid availability starts dropping under 99%.

      So, what I need to do is determine my “grid up time percentage target” that I think will be the most likely worst case. For this, I have to totally guess… there is no way to predict this. I could guess anywhere from 98% (Meh, the power is out less than a day a month. Deal with it, princess!) on down to 0% (OMG! It’s “The Road” style nuclear winter or some freakish total grid collapse!) Realistically, what I’m actually doing is setting my threshold for what I’m willing to compensate for. If the actual number goes lower than that, I would need to modify my strategies.

      I’m going to set that target at 75%.

      That means for 3 days of every 4 (on average), the grid is up, but sporadically comes down such that the total up time is only 75%. For this, I need a combination of conservation and batteries with some way to recharge the batteries before they get to 50% DOD.

      As an aside, since I’m base lining this off the grid being up 75% of the time, and the majority of the cost is actually in the Inverters and Batteries that have to be there anyway, it would be nice to sell back the extra power while the grid is actually up. I would never build a system just for that purpose, but as long as the system needs to be there for the 25% of the time the grid is down anyway, might as well take advantage of the sell back during the 75% of the time it’s up.

      As such, the “sell back” only needs to consider the cost difference between the fully off grid version of the system and the hybrid Grid tie w/ backup version. The extra expense is small, and would start paying back very quickly.

  12. alta chica del sol says:

    Bob,

    Like I said, you know everything and there’s absolutely nothing I can teach you.

    Once you design a system to run for 3 days with no grid, you’re all the way into “off-grid” territory, or you’re somewhere between “off-grid” and “two lights and a laptop”.

    If electricity is that important to you, I suggest you stop guessing and hire a competent solar installer. You can’t learn this stuff by posting to forums, and you can’t learn if you insist on guessing.

  13. Bob says:

    alta chica del sol,

    “Once you design a system to run for 3 days with no grid, you’re all the way into “off-grid” territory, or you’re somewhere between “off-grid” and “two lights and a laptop”.”

    No, there is a third state where you’re into off grid territory only a percentage of the time. The difference is how long your batteries need to power the system before you cycle them so fast you reduce their usable lifespan.

    If you hire a man to fish for you, you eat for a day. If you learn to fish yourself, you not only eat forever, but can constantly learn to catch new fish.

    • alta chica del sol says:

      Bob,

      That territory doesn’t exist. I’m sorry it doesn’t exist, and I’m sorry you haven’t a clue what you’re talking about.

      You could design a system that was “batteries-only”. You buy a large enough bank of batteries to maintain your lifestyle for 1 or 2 days, at some regularly scheduled interval of being without the grid.

      That’s how off-grid homes are designed. They have massively huge battery banks that provide all of their power for when the sun doesn’t shine for a day or two. You’ve substituted “grid isn’t up” for “sun doesn’t shine”, but it is the same thing.

      To do the design, take 2 days (because if “1” is expected, “2” is what you’ll get) worth of however much electricity you expect to use and multiply that by 5. That gives you a 20% design depth of discharge. Now, divide that by the conversion efficiency, taking battery voltage depression into account. That’s about 70 to 80%. Do the math with your energy consumption.

      What you’ve decided, with this “hybrid” idea you’ve got, is that you’re going to design an off-grid home for the worst possible climate on Earth. In your world, the sun never shines and the grid that you have decided you can’t rely on, is reliable enough that it is going to come back before your batteries collapse and are ruined.

      I’m morally opposed to making you look stupid, but I’m also morally opposed to you confusing the people around you. Go hire a competent solar installer and have a properly designed system installed.

    • Bob says:

      No, you’re not seeing it at all.

      “To do the design, take 2 days (because if “1″ is expected, “2″ is what you’ll get) worth of however much electricity you expect to use and multiply that by 5. That gives you a 20% design depth of discharge. Now, divide that by the conversion efficiency, taking battery voltage depression into account. That’s about 70 to 80%. Do the math with your energy consumption.”

      That’s the normal mechanic, with the grid never up (Design philosophy 2), and the batteries specced to hold the system through the 90% uptime window. The result is a huge battery array with high installation and maintenance costs.

      “In your world, the sun never shines and the grid that you have decided you can’t rely on, is reliable enough that it is going to come back before your batteries collapse and are ruined.”

      Not correct. Nothing is stopping you from having Solar panels to charge the batteries when the grid is down and the sun is up. There is also nothing stopping you from having a generator as a tertiary charge source. Obviously, you can’t let the batteries get too low.

      You have 3 charge sources. The grid is the primary one, keeping the batteries in float 75% of the time, then solar when the grid is down and the sun up, then the generator when both are down or solar wasn’t enough. When the grid is available, you also have the ability to sell the extra solar to the grid.

      You’re looking at the grid as if it’s a binary thing, Always up or Always down. It’s true that historically, that has been the case. But historically, the globe has not been in an economic collapse possibility like it is now. All that would need to happen to reduce grid reliability as I’ve described is a combination of bank holidays and slowdown of cash flow / workers in power company maintenance positions. Stuff doesn’t get fixed fast, rolling blackouts occur, storms result in longer shutdowns.

      That’s what “Prepping” is about. Predicting failure and preparing for it. That’s why we have stores of food even though the local supermarket has never closed before. And stores of fuel even though the gas station has always been there.

    • alta chica del sol says:

      Bob,

      I am seeing it. I design these systems, and their controlling and managing components, for a living.

      Each added “component”, whether a “charging component” or a “storage component” or a “power conversion component” has a cost and a design complexity.

      If you are planning for a “grid-down” emergency, you have to actually plan for the grid to be down. You can’t assume the grid is going to be your charging source when you are designing a system for an unstable or unreliable grid. That’s idiocy — when mitigating the risk of a loss of a resource, that resource is NOT allowed to appear as a primary source of anything. That’s the whole purpose of risk mitigation — you remove the resource, you don’t rely on it.

      Planning to fully recharge from the grid in the States in a “grid-down” environment is folly. The utilities have AMR (“Automatic Meter Reading”, aka, “Smart Grid”) in place and if you decide you’re still going to consume 100% of your energy when the grid is in some kind of “rationing mode”, you =will= be turned off. That’s assuming you’re the only one with this bright idea, and the grid doesn’t have either a voltage or frequency collapse when the rest of your friends all get the same bright idea.

      That alone puts your system needs squarely into “off-grid” design territory.

      However, that’s a “utility decision”. From an operational standpoint, systems that are installed in “unreliable grid” environments (I have clients in South America, the Caribbean, Africa and Asia where the grid already is what you’re prepping for) are properly done to off-grid standards simply because they must be. If they aren’t, you have high DoD cycles on the batteries, and that’s murder for them. One or two severe discharges can completely destroy even the best batteries.

      Properly designed systems are far less expensive than what you keep guessing at, and are far more functional. In addition, your entire risk mitigation strategy is utterly backwards. When you are mitigating the risk of a loss of a resource, you DO NOT use the resource in your plans. If the grid is unstable or unreliable, there is a REASON for it, and it isn’t because the utility workers decided they aren’t going to work 2nd and 3rd shifts.

      The other issue is that if we’re in a large scale grid-down environment, Black Start becomes a huge problem and it can take DAYS to restart the grid. That’s an off-grid scenario. The existing DC interties between the Eastern and Western Interconnections aren’t going to make it take less than days. Even if Tres Amigas is built, it will take days.

      If you’re just planning for a natural disaster — another Hurricane Andrew or Katrina — there may not be a local grid for weeks on end. I rewired a number of buildings in Katrina Land that had the only power for blocks around, and even that was unstable for weeks. Again that’s an “off-grid” design decision. I have a friend in Houston who had the only electricity for two weeks, because he had a properly designed system, designed to off-grid standards. I had the only reliable power on my block during the rolling blackouts we had last winter. Again, a properly designed system, designed to off-grid standards. I’ve already had clients with systems that had the grid go down this hurricane season.

      FWIW, my initial install was a whole-house backup, designed to handle a four hour outage. That was the “historical maximum outage experience”. The cost “bump” to get to the required “average daily load” (a “daylight plus four hours” outage) amount of AC production would be about $2,000 today. That would give me average daily consumption, with low battery requirements, provided I used major appliances wisely — during daylight hours. Getting the batteries up to where they are at present was about another $2,000. No need for generators, no need for “fuel stabilizers”, no need for all the other glarp you have in mind, and I can run a 3.5 ton central A/C, not just some deep well pump. The “bump” to get to “early summer” loads (that is, higher A/C requirements — yes, I run A/C from my already existing inverters) is $8,000. From there, the “bump” to “extreme summer loads” isn’t a whole lot more.

      Going back to your “hybrid” explanation, the “upcharge” from a 4 hour outage designed system to a properly designed off-grid capable system, able to run central air conditioning, is $12,000. That’s why “hybrid” doesn’t exist. The design decisions to produce a “hybrid” system are economically idiotic. My current average year-round electric bill, including blisteringly hot summers, is $45. Because it was well-designed (designed it myself …) from the outset, I can add PV charging capacity with a 25 year lifetime for far less than you can buy and operate a generator.

      A Cheap Chinese Crap generator is good for perhaps 1,000 hours of operation, which means you get perhaps 1MWh out of it for $500 and $3,500 of gasoline. For $4,000, I can buy 1.3kW of panels which will produce 5.1 average hours of sun at 95% efficiency for 25 years with a 95% average output. That’s 54.6MWh. Your choice — generators that make 2% of what PV will make, or PV. If you think paying 50 times more is a good idea, you have right at it.

      Go hire a real solar installer. It’s only 50 times cheaper that your solution.

    • alta chica del sol says:

      Correction to the above — that $45 average monthly bill includes taxes, fees, surcharges, etc. My actual average bill is $38, without all that extra crud.

    • Bob says:

      alta chica del sol,

      Let’s try this again.

      The system is comprised of a grid tied 120/240 inverter, batteries, solar panels, and a charge controller. This is exactly like your own system. Since I have no way to know how many batteries, solar panels, etc you have,,, I cannot compare.

      When the grid is up, which is most of the time… the inverter’s charger is in control of the batteries. Most of the time, all it has to do is keep them maintained. While it’s doing this, the Inverter goes into “sell” mode and sells power back to the utility.

      If the grid goes down for a day or less, when it comes back up that main charger comes back on line and does it’s job. This is a typical short power failure. Whether the solar panels managed to apply any charging or not through the Charge Controller is really not important… the power came back well before the batteries got below 50% DOD.

      When the grid goes down, your first job is to turn off the stuff you don’t want on during a “Power failure” to put the total daily load below your “Off grid” set point. I’m using 7.2 kWh per day for this.

      Depending on the time of year, and what quality of sun you’re getting (clouds, etc.) the Charge Controller connected to the Solar Panels may be able to keep the batteries fully charged each day. If it can, great! If it can’t, you have 2 options. 1) Lower your “Off grid” set point to make the batteries last longer. or 2) Run the generator for a while early in the morning as the sun comes up. That charges the batteries in “Bulk mode” and sets the Solar Panels up to finish off the charge over the course of the day.

      As such, the grid is the primary charger, as it always takes precedence if available, the Charge Controller connected to the Solar Panels is the secondary charger, and is your main charger while in “Off grid” mode, and the generator is the tertiary charger, used only when the “Off grid” period is extended and the Charge Controller isn’t getting it done.

      I don’t know about where YOU live, but I live in the middle of nowhere, we have LOTS of gasoline and diesel powered equipment around the farm. As such, I already have fuel stored, it’s no extra effort. I already have to make sure engines aren’t left inoperative for periods long enough for the fuel to go bad. I already add “Sta-Bil” to my gas supply.

      How is this different from a full “Off grid” system? There aren’t as many batteries. I only need enough batteries to ensure discharge can’t get below 50% DOD in 24 hours even with no sun. If that happens for days (or weeks) at a time, that’s the worst case scenario and I’ll need to run the generator a lot. (A few hours every day the sun doesn’t shine.) But how often is that going to happen? Even if I have to run the generator like this for 4 weeks a year, it will still last over a decade.

      Why is this? Because when the grid is UP, the batteries don’t discharge at all. They only cycle when the grid is down, this allows the reduction of the total number of batteries without sacrificing the expected total number of battery cycles during their life.

      As to hiring a competent solar installer, Why? You did, and you still had to re-figure your system twice after the initial install. I’ll make my own mistakes, thank you.

    • alta chica del sol says:

      Bob,

      I didn’t “refigure” my system ever, and by the time it was designed, which I did myself from the start, I already knew how to design electrical systems for specific purposes. I don’t install solar systems. I design them. I designed mine, even while my installer was trying to cut my costs by selling me the wrong system.

      Your “design” won’t work because the first “hour” is the most expensive. A “one hour, whole house standby” system already requires all of the power conversion gear for whatever AC loads you want to support. Since you can’t control when the grid goes down, either you size your inverter for all your loads (what I did), or you add complicated control equipment, which adds cost and complexity so you can juggle loads around. That second inverter was actually cheaper than having the main service panel heavily modified and adding various critical loads panels with transfer switches installed. See, all the components in a system have costs. A “panel upgrade” would have been $2,000 and added no functionality. The second inverter was $1,800. I saved $200 and added functionality.

      In your case, you might not need 240 power for an hour, but you would for a “day”. By the time you get to a “day”, you are well on your way to needing an off-grid design, or else you’ve relegated yourself to “two lights as a laptop”, as you put it. You would need virtually all of the AC output, unless you’re able to live without that deep well pump for a day. You must design for the peak loads, not the “run around like a crazy man flipping switches” loads. Unless you want to do that, and pay for the extra switch gear to allow you to do that.

      The other problem with your design is matters beyond your control. Thanks to AMR, the utilities know who you are and what you do. So forget this “recharge from the grid during a grid problem” scenario. If you are in a “rationing” mode, you will get “rationed”. If the utility discovers you’re applying a huge load to the grid, you will get disconnected. They can do it without sending anyone to your house. When I’ve had fights with my electric provider, I tell the person on the other end of the phone to check my daily meter reads so they can verify I don’t need them and they can’t make me need them.

      The inverters don’t actual control charging when the grid is up. It’s a coordinated effort between the charge controller, which is trying to fully charge the batteries, and the inverter, which is trying to sell the excess. It turns out that if you have too small of a battery bank, for your solar array size, you will experience severe instability, especially with maintenance free batteries. Sizing a battery bank to an array is very difficult and requires years of experience. That you don’t have.

      There are various design guidelines for sizing batteries, and none of those allow you to “just wing it”. Go too small and your “sell-mode” is unstable, which is a common design mistake for people like you. Go too big and you wind up with “float losses” being your single largest daily load. There is a “just right”. That or you wind up with a broken system.

      Also, you can’t just ignore the batteries. They have to be exercised, but that’s probably too advanced a topic for you to understand. You think gasoline needs to be stabilized, and farm equipment maintained, but you don’t understand that sulfuric acid stratifies. Which is does. That causes plate erosion and battery failure. Acid is nasty stuff, even in lead acid batteries.

      The other problem is that 50% DoD, as a design point, is suicide, especially if planning for a “grid-down” type of event. This is why 80% DoD is the most common design point, and that’s 5 days of consumption. The chemistry of the electrolyte changes as the batteries discharge and at some point, the electrolyte becomes “watery” enough that the plate material will actually dissolve into it.

      So, now you have a system which must be able to support most of your AC loads. You can do this with expensive upgrades to your service, and complicated switchgear — neither of which add value or function — or you it by having an inverter that has the required capacity, based on something else you don’t understand called “Load Diversity”. The cheapest solution is to have inverter capacity, and I have 7.2kVA compared to the 4.4kVA you suggested. Because of the inverter design I went with, if I needed it, I could have an effective 14.4kVA, but my peak demand is 5.4kVA, so I don’t need it. You would be stuck with 4.4kVA, or 1/3rd what I can have. I can start, and run a central A/C unit, you, well, you wouldn’t be able to without running a generator.

      Once you’re all-in on the inverters, you have to size your solar array. You could ditch the solar array, but as I already showed, “generators” are an order of magnitude (and a half …) more expensive. Generators are a liability. Solar panels make electricity and are an asset. If I hadn’t gone with the solar array, and went with a generator instead, I’d likely have needed to replace my first one (the system is five years old) already and my electric bills would be about double.

      As with the rest of the system, once you decide your generator is your “primary backup charging source”, because you really cannot sanely claim the grid is your primary charging source for a system designed to provide power when the grid is down, you’re fairly committed to going “all in”. Those Cheap Chinese Crap generators still die within years, and you’re back to paying money for what solar does while it makes money. So, let’s say that a Cheap Chinese Crap generator last 5 years doing “standby” duty, and you run it that same 1,000 hours in five years, making the same 1MWh. That’s the same $4,000 every five years — generator, fuel, maintenance, etc. — or $20,000 over the 25 year design lifetime of a solar array. That $20,000 nets you 5MWh, none of which you can sell back to the grid. The same investment — $20,000 — nets you about 185MWh, or roughly 35 times more energy. So you know, I used a higher cost for the $20,000 install because you can’t just incrementally add that much PV. If you wanted to add 1MWh per year of PV, it would be much cheaper — about $1,800 — and that would be a one-time cost, not $20,000 over 25 years. On a cost-comparison basis, that’s merely 11 times cheaper than what you’ve suggested. That doesn’t include the value of the electricity made, and 25MWh is worth about $2,600. When netting out “cost” minus “savings”, the PV pays for itself. Cheap Chinese Crap generator doesn’t. You can pay $20,000 over 25 years, or you can make $800.

      Your choice, as usual. You seem to want to install and expensive, useless and broken system. I hope the readers here realize that you’re planning for failure and consider something that’s cheaper, more functional, and much more reliable.

  14. Jalapeno Gal says:

    I have been following the conversations here and I am hopping that we can keep this conversation friendly because I feel everyone here has information to share so that people can *choose* what is right and best for them and their families. It is not a competition. Some people can only do so much to prep and having multiple options gives them things to plan for and build towards. Thank you all for sharing your knowledge with us and please, lets stay friendly.

    Thanks,
    JG :)

    • alta chica del sol says:

      I’m in the solar business.

      Some people respond well to facts and experience. Others latch on to bad ideas and try spreading them. Those people need to be rebutted before others rely on their horrible advice.

  15. Bob says:

    alta chica del sol,

    “I didn’t “refigure” my system ever, and by the time it was designed, which I did myself from the start, I already knew how to design electrical systems for specific purposes. I don’t install solar systems. I design them. I designed mine, even while my installer was trying to cut my costs by selling me the wrong system.”

    Well, perhaps you should have stopped him before he installed it wrong. Twice.

    We’ll continue!

    “Your “design” won’t work because the first “hour” is the most expensive.”

    Wrong. All you need to do is set your system up so that it DOESN’T go into auto backup mode. When the power fails, it fails! You then wait a bit to make sure the power has REALLY failed… then go around and turn off the stuff that needs to be turned off and push the button on the Inverter that starts the battery backup.

    Really… HOW OFTEN DOES THE POWER FAIL? Not very often.

    “You must design for the peak loads” Did that. It was easy. I included the well pump in my 7.2 kWh per day requirements.

    “The other problem with your design is matters beyond your control.” That’s why you have Solar Panels. Duh. Was that not clear? If I’m in Rationing Mode, the grid is unstable and I’m using the panels and generator.

    “The inverters don’t actual control charging when the grid is up.” Oh? Well, your small battery bank doesn’t seem to be a problem. I expect mine will be Ok.

    “There are various design guidelines for sizing batteries, and none of those allow you to “just wing it”.” True! You had to try 3 times before getting it right. I hope I can do it in less tries.

    “Also, you can’t just ignore the batteries. They have to be exercised, but that’s probably too advanced a topic for you to understand.”

    I’m insulted. I understand the needs of the batteries. For example, FLA batteries need to be equalized every few months to combat sulfication of the plates.

    “The other problem is that 50% DoD, as a design point, is suicide” I’m not 100% on this one, but it seems clear that this is an off grid concept only… it applies if you ALWAYS deep cycle your batteries. Since I, Like you, intend to be on the grid at least 75% percent of the time… this won’t be an issue.

    “So, now you have a system which must be able to support most of your AC loads.” Huh. I’m good. Amazingly, I’m not as stupid as you think.

    “Once you’re all-in on the inverters, you have to size your solar array.” Yeah, I’m going with an 8 panel array making about 2K peak. Average will be way less. of course.

    “As with the rest of the system” At this point, you have jumped the shark and I can totally ignore you. Are you insane? NO ONE would think powering a system with a generator 24/7 is a good idea. Where do you get this crap? Obviously not from anything I have posted.

    • alta chica del sol says:

      Bob,

      I haven’t the slightest idea why you keep misrepresenting how my system was designed and installed. You’ve done this several times. Dishonest much?

      The system’s original design point, and how it was originally installed in what was the first of three stages, was as a four hour whole-house backup system. Based on the previous five years of experience with power here, that was the “three sigma” design point — there had never been an outage of more than four hours. The second stage provided for fairly normal daylight-hours-only operation of all loads. That was 12kWh, and the second stage increased the array capacity to that point. Nighttime loads would have to be reduced to a minimum so that “four hours” worth of batteries would make it through the night, which they managed to do. The third stage removed the need to limit consumption to daylight-hours-only. This was done by expanding the battery capacity.

      Based on system testing, typical morning state of charge was 80% (20% DoD). The design was solid enough that my first test resulted in staying off-grid for nine days straight. This implementation schedule was very intentionally done to avoid having all of the costs incurred upfront. The increased cost to go from a four hour solution to where I’m at now was only 15% of the total cost, but it was a very carefully, and very precised designed 15% of the total cost.

      Now, you’ve clarified your design point a bit better. I’m now going to explain why what you’ve “designed” is a complete failure.

      You don’t know when the power will fail, and that includes whether or not you’ll be around. That means you risk having all that food in your fridge spoil, having no water because the pump hasn’t run in a few hours, and so on. What’s the point in having a system if it doesn’t do what it’s supposed to do? There’s a cost associated with every risk, and you’ve designed a system which has built into it being inconvenienced, losing food, water, and running around and flipping switches. Mine was designed to not be inconvenienced. When we had rolling blackouts last summer, my A/C kept running. It was very nice, and no switch flipping.

      There are mechanisms in most inverters to turn themselves off if the batteries get run down. You don’t have to run around turning things off, you simply put the “must run” loads on the inverters through something called a “critical loads panel”. Except that as I explained, a “critical loads panel” is a system component with a cost that cost provides no functionality. It doesn’t provide electricity, it only compensates for the lack of electricity. In my case, the second inverter was cheaper than a “critical loads panel”, and so long as I had a power outage within 3 standard deviations of the mean (99.7%), my house wouldn’t even know the difference. That was just with the initial design, and that’s why it was the initial design. It was a system that covered 99.7% of the actual experience of power outages. Not “extraordinary” events, the historically experienced events. Not “economic disruption” or “natural disaster”, just the normal and ordinary events, without having to run around and flip switches or throw out spoiled food.

      What you’ve described is what you decried — two lights and a laptop. Something called “load diversity” insures all of your loads aren’t on at the same time. Without the A/C going through the inverters, my loads average about 450 watts when I’m awake (if the TV is off) and maybe 600 if it is. Peak inrush load is around 2,500 watts when the fridge kicks in, so I have to plan for that, and so do you. If your well is your single largest load, you have to plan for that. Without running all of your “basic” loads through the inverter, you’re wasting inverter you already paid for. By designing the system to “run around turning switches on and off”, you are wasting money. This is why I say you might as well go “all-in”, because the inrush currents must be covered and they are much higher than the average loads. Cover those transients and you more than cover your tare loads.

      And yes, you aren’t 100% on the concept of avoiding 50% DoD. Design depth of discharge determines discharge rate, which affects system reliability. Higher rates of discharge, as reflected by higher design DoD over a fixed interval, produce less stable and less reliable systems. Voltage depression at higher rates of discharge can lead to inverter shutdown, and through something called “Peukert’s Coefficient”, greatly reduced capacity. It also leads, as I pointed out before, to permanent battery damage as the plates become soluble in water, which is what the acid in a lead acid battery becomes, at high DoD values.

      Inrush currents, from starting large inductive loads (fridge, freezer, air handler, well pump), lead to transient voltages which can come very close to the low battery cutoff. At high DoD values, the reactions which create electricity become slower, which leads to rapidly increasing “crack of the whip” voltage drops. That’s the sharp drop in voltage on a deep discharge battery when a large load is suddenly applied. The voltage drop progresses exponentially — the higher the DoD, the greater the “crack of the whip” in an exponential manner. The opposite happens, by the way, with small batteries that are fully charged in grid-tied systems. Cloud edge effect (high power output transients caused by lensing at the edge of clouds) can cause high voltage transients which can cause inverter shutdown or damage due to over-running the maximum battery voltage. You’re damned if you do, and you’re damned if you don’t.

      it isn’t just equalization that’s required, nor is it just sulfation that needs to be avoided. Without being exercised, the density of sulfuric acid at the bottom of a cell will greatly increase, causing permanent damage to the bottom of the plates. This is called “plate erosion” and is a common cause of battery death on poorly designed systems that don’t die first from sulfation or being overly discharged. Without daily exercising, you gradually lose battery capacity, as much as 10 or 20 percent over the course of a month. For a system with a design DoD of 50%, you no longer have 50% of your capacity to work with, you only have 30%. Because you only have 30% to work with, you experience greater battery voltage collapse, system instability, then failure. The system becomes pretty worthless pretty fast, and then you have to go start that generator or pray the grid returns.

      If you compensate for that set of problems, which would be a good idea, the solar array you have is now too small to keep the batteries properly charged, or else you waste “sell-back” capacity to float losses — the 2 or 3 percent of battery capacity that must be constantly applied to the batteries to keep them topped off and prevent sulfation. With a too-small array and battery bank sufficient to not risk destroying the batteries, you’re losing a large fraction of your production to keeping batteries from becoming sulfated.

      The short answer is that the entire system is an inter-related whole, with various design decisions affected other design decisions.

      Peak load determines battery capacity the same as total energy requirements. Go too small with the batteries, and the “crack of the whip” from high transient loads (inrush current) can cause inverter shutdown. Go too high with the design DoD and you lose nameplate capacity, risk system instability and permanent battery damage. When you increase the battery size to support the loads at a more reasonable design DoD, you now have issues with solar array size. Have too small of an array and you risk chronic under-charging, sulfation and battery death, or excessive float losses. If you don’t increase the battery size, but do increase the array size to cover loads, you risk instability during selling, or battery damage from high voltage transients caused by the “cloud edge effect”.

    • Bob says:

      The whole switch flipping part…

      What was I thinking? Yeah, that’s really stupid. I’ll just install a separate panel for the non-backed up loads. Piece of cake. For my usage, that A/C units and the hot water heater are the only things on the non-backed up panel.

      “I haven’t the slightest idea why you keep misrepresenting how my system was designed and installed. You’ve done this several times. Dishonest much?”

      Since your system configuration is a big secret, I have to assume based on what you tell me. And what you tell me has confusing parts. For example, isn’t it a big no-no to add batteries to an existing bank?

    • alta chica del sol says:

      Bob,

      The configuration of my system isn’t at all secret, or a mystery. The exact specifics are simply irrelevant because it was sized to meet my needs. Your system would have to be sized to meet your needs.

  16. Bob says:

    alta chica del sol,

    Also, this part makes little sense:

    “That second inverter was actually cheaper than having the main service panel heavily modified and adding various critical loads panels with transfer switches installed. See, all the components in a system have costs. A “panel upgrade” would have been $2,000 and added no functionality. The second inverter was $1,800. I saved $200 and added functionality.”

    Good lord! What are you building? Modifying the Load Centers is a breeze, the parts are available at Home Depot. You want to add another? A hundred bucks in parts and if you have to hire an electrician… some money there, too. But not thousands of dollars!

    Adding an Inverter seems far more complex than that! Since Inverters are not standard electrical parts that you can get at Home Depot… you also need a semi-custom panel to mount it to (About another 500 bucks alone.)

    Why would you ever add an Inverter simply to prevent having to add another Load Center? You add an Inverter to add capacity… the parts to distribute that capacity (Load Centers) are cheap by comparison.

    I had also assumed that you had 2 Inverters in order to master/slave them together into a single 120/240 unit. (Based on the cost and wattage, that sounded like Outback Power 3600 watt, 48 volt units. Connect them together and you get one 7.2kW 240 volt Inverter.) But no… apparently, the second inverter was added just to avoid adding more Load Centers. This means BOTH Inverters are 240 volt capable.

    What are you building? And how much money are you spending on it? You indicated that the “upgrade” was 15% of the total cost, and that the upgrade was 4,000 dollars.

    Let’s see:
    “The increased cost to go from a four hour solution to where I’m at now was only 15% of the total cost, but it was a very carefully, and very precised designed 15% of the total cost.”

    And:
    “FWIW, my initial install was a whole-house backup, designed to handle a four hour outage. That was the “historical maximum outage experience”. The cost “bump” to get to the required “average daily load” (a “daylight plus four hours” outage) amount of AC production would be about $2,000 today. That would give me average daily consumption, with low battery requirements, provided I used major appliances wisely — during daylight hours. Getting the batteries up to where they are at present was about another $2,000.”

    The total cost where 4K is 15% is 26K and change. Wow. You have a lot invested in this.

    • alta chica del sol says:

      Bob,

      Yes, solar power was more expensive years ago when the system was put in.

      All you do is run around guessing, because you have no clue what you’re talking about.

      Segregating loads in an existing home requires that you run a separate feeder from the inverter(s) to the same location as the existing load center. The existing load center must then be disassembled, more or less, and the wiring from the loads you want backed up must be extended (not all that easy) to reach the backup loads panel. Unless the house was wired in conduit, that’s a pretty non-trivial exercise, and I’ve likely wired far more electrical panels than you, including buildings that were wired in conduit.

      All of that expense is non-functional. It doesn’t produce electricity, it only makes up for the lack of electricity. It doesn’t increase your convenience or standard of living, it increases your inconvenience and locks you into having a couple of lights and a couple of supported receptacles for specific dedicated loads.

      Your approach may not even be feasible, depending on how the original branch circuit wiring was done. If you want to include “lights” in various rooms (try peeing and washing in the dark, without running around with a flashlight), but not include “receptacles”, you might have to rewire branch circuits so that “general lighting” is available (not having just two lights) available, but receptacle loads (not being stuck with just the fridge and a laptop) aren’t.

    • Bob says:

      “Yes, solar power was more expensive years ago when the system was put in.”

      And yet, you deemed it cheaper to add another inverter rather than rewire some standard electrical parts.

      See my confusion? That makes no sense. You can’t just add an inverter, you also have to add the source of power for that inverter, and it’s interface components. Unless your walls are solid concrete or encased in carbonite, making it impossible to modify the wiring within, it’s going to be cheaper to modify the load centers than to add capacity. A LOT cheaper. Especially considering that inverters don’t just connect into your load center by themselves, they need their OWN panel components. I’m finding that you need to allocate 500 to 800 extra dollars per inverter to buy those extra parts. And that’s in today’s prices, where you can get pre-wired interface panels for the inverter. Apparently, it was “More expensive” back in the day.

      Here’s an example: This is the current inverter I’m looking at:
      http://www.wholesalesolar.com/products.folder/inverter-folder/xantrexxw4548.html

      Wholesale Solar is my first go-to site for this stuff. Sometimes I have to go to the equipment manufacture’s site for more detailed specs… but Wholesale Solar is usually good for preliminary info.

      The support panel for that inverter sold by Wholesale Solar is a Midnight Solar product:
      http://www.wholesalesolar.com/products.folder/disconnect-folder/MidniteSolar/mne250xwe-panel.html

      Schneider makes their own panel, that mounts to the right of the inverter as opposed to below as the Midnight Solar panel does. I haven’t fully decided between the two? But I’m starting to really warm up to the Midnight Solar one. This is mostly because I only intend to install one inverter.

      I had to use my google-fu to find an installation PDF for that inverter. If features the Schneider support panel, that in conjunction with extra conduit boxes, can support multiple inverters:
      http://www.dcpower-systems.com/uploads/products/22157_2.pdf

      The other thing you’re doing that confuses me is insisting that your 3.5 ton A/C unit is battery backed up. That monster takes… what? 20 amps at 240V while running? You cannot possibly have been running that during your 9 day off grid test. Which loops back to the whole “switch flipping” discussion: Won’t that monster load drain your batteries before you can get home to turn it off? After all, as you have so astutely pointed out, you have no idea when the power will fail.

    • alta chica del sol says:

      Bob,

      If you know what you’re doing, you really can just add that second inverter. It’s an extra DC circuit breaker, and one extra pole on each of what would have been a pair of single pole circuit breakers. The wiring typically has to be run in conduit, so instead of pulling three #6 conductors, four get pulled. The #4/0s from the DC bus to the inverter are a couple of feet at best.

      The actual cost to add that second inverter is quite small (and very well worth the expense, given the flexibility it provides), and the $2,000 panel upgrade is a low-ball value. For my house, because of how the inside panel (60A 24 slot distribution panel) is wired, it would have been significantly more to have lights in the common areas (den, dining, kitchen, baths), refrigerator, and one or two counter top outlets in the kitchen. As an aside, when wiring a home it is best to separate the lights from the outlets. Not that my builder did that, since it tends to be cheaper to hit the lights with the home run, then branch off from the light switch JB to the outlets around the walls. If you don’t separate the lights from the outlets, you have all manner of problems. Unless you get that second inverter.

      You’re thinking in terms of a complete novice. The balance-of-system parts many vendors push are their high-markup items. Most inverters are priced by the watt on the high end, which drives their margins down. A competent installer will make sure you get the components that are suitable to your level of skill. For someone who has little or no skill, a fancy load center is probably the right choice.

      You also haven’t a clue what the run amperage is for my A/C unit. It’s a dual-speed, 20.5 SEER scroll compressor based unit. On “low speed”, which is where it usually runs, it draws about 9 or maybe 10 amps, and that includes the blower (evaporator) inside the house. When it goes to “high speed” it gets up to around 12 to 15 amps. But in the interest of full-disclosure, no, the A/C wasn’t being used when I dumped the grid for 9 days. I do have plans to make it so I can have A/C for days on end without the grid, but since the grid has never been down for more than 4 hours here, I think I’m okay the way I am. Seeing as I can run the A/C for 4 hours (I can run it for longer than that, but we’ve never had an outage go more than 4 hours), I’m happy with what I’ve got.

      The bottom line is this — this is what I do for a living.

  17. I liked the article but am not the biggest fan of generators. It is a good idea to get a backup generator but with today s technology I would recommend looking in to Tesla, Geo thermal, solar or wind.

    • TheDude says:

      Intriguing dialogue…While I am late to the party, I want to share what we did…bought a JASPak Solar Generator. We did tons of research and sifted through the garbage out there and found this one. You want to run a fridge/freezer and have power to spare and recharge in a few hours? – go look at these folks! It is a bit heavy – but we use it ALL THE TIME away from the house, even without the solar panel. These guys have it all, and then some. Just sharing…

  18. I did this 5 years ago and i did reduce my power bill. Only problem was that PSE&G ( my pow co) raised my delivery charge through the roof so i was still paying the same amount even though i was making and using my own power. The only REAL way to win is to be 100% off grid and tell them to pull your meter!

  19. Jerri says:

    Yes! Finally someone writes about self storage business.



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