Off Grid/Grid Tied Solar Design Education

I'm a pretty experienced PV designer (over 500 designs ranging from 2KW to 2MW) and have been diving into permaculture with a passion in the past few months. I've tried to see if there were any good resources to teach oneself how to design an off grid or grid connected PV system and have not found many of quality. As most permies tend to be the research oriented DIY type I thought that there may be a demand for it.

I've been thinking of putting together a detailed website with an educational bent that would teach someone the basics of solar and good design principles if one wanted to design their own system. This would be completely free with the idea of putting it into an ebook or something of the sort in a year or so.

Is there interest in this sort of thing or has this need been met somewhere else that I'm not aware of?

Thanks, and if this is something you'd be interested in what are some of questions that you'd like answered?

very interested I would love to have some beginner stuff , for those of us with no education on the subject but lots of interest

Alex - I think this is a GREAT idea.

Here are some questions I would ask:
--here in the city, solar is mostly grid tied. People are under the assumption that if the power goes out, they will still have power indefinitely. In fact, this is one of the biggest motivators for getting solar. If urbanites want to be truly energy independent, what should they do?
--Solar panels are very expensive. What steps should people take to reduce their overall energy usage before they size their system? Is there some kind of break even point in the industry?
--What is your take on rented solar panels that have become popular in some areas? What are the up- and downsides to them?
--What kind of rebates are out there from various government/private entities to help people with the purchase price of solar systems?
--What are some of the new innovations in solar?

I echo Jennifer's questions and have one BIG recommendation for you.

DIYers are motivated but not versed in the language of whatever venture they are diving into. Most people who are experts in something usually speak in that language which is gibberish to the layperson. If you put education materials together, please keep in mind we don't speak your language. Don't assume we know anything. Assume we know nothing. Assume we don't know the difference between volts and watts. Assume we don't know what "in series" is or "in parallel" is. Assume we don't know what "three phase" means. Yes, in this field there is a certain amount of technical terminology that will be difficult to get around, but that's what a good communicator does, they translate their knowledge into the language of the audience. Frankly, it's why the "______ for Dummies" series is actually pretty popular. If it were me, I would be sure my diagrams are something a 14-year-old person can understand and avoid all that schematic looking stuff. Remember to keep in mind you will be teaching people who are not solar geeks and that will steer you well as you develop materials. Remember, you're not training PV professionals, you're training DIYers.

I love your idea and would be a student of yours if you can pull this off.

More questions.

--one of the selling points for grid-tied systems is the oft-touted "you can sell extra energy back to the grid". It makes it sound like during certain times of the year, your system could pay you back. In reality, I've never heard of this actually happening and I know a fair amount of people with grid-tied solar. In your experience, should people have the expectation that they could make money selling back to the grid?
--this one is kind of "out there". I love the idea of "community solar". I define this as a neighborhood or part of town or even a village coming together to build a system to provide for their power needs. Do you know examples in the USA of this being done? I've only heard of one and I know those folks had to deal with a TON of red tape. I ask this question because here in Phoenix I live in one of the neighborhoods surrounding the AZ State Fairgrounds. The fairgrounds has a ton of roof surface for solar and could possibly provide for a small neighborhood's needs. The fairgrounds is used mostly during our cool season (Oct through May) and not during the blistering hot summers. So it's almost the ideal situation - during the hot summers, the fairgrounds are fallow and the 'hood needs the energy for AC usage. During the cooler months, our electric usage in the 'hood goes way down but the fairgrounds starts hosting events (the state fair is three weeks in Oct/Nov) and can use the excess power. And while I know that this project is somewhat of a pipe dream at the moment - it doesn't stop me from pondering it!

What Dan said!

Could be that this project is turned into a Kickstarter campaign at some point...

Alex, one of the things I come across time and again and would be great information to include is the need to charge lead-acid batteries at an appropriate charge rate. Far too often I seen systems with large battery banks and undersized PV. Addressing the issue of bank size vs. PV size will greatly help newcomers from experiencing premature battery failure as the result of electrolyte stratification and accompanying sulfation. I am currently installing my second system. The first was a small off-grid to power my horse barn. The system I'm installing now is a 1kw, hybrid grid-tie/off-grid to run my freezer and fridge.

For Dan (and others):

Lead-Acid batteries contain a solution of electrolyte (typically sulfuric acid). This electrolyte interacts with the lead plates contained in the battery to provide a flow of current. As the battery discharges, the eletrolyte changes in it's specify gravity. As it charges, it's specific gravity rises. When a battery is kept in a stationary position, this continuous rising and falling of it's specific gravity causes the compounds in the electrolyte to somewhat separate into layers (stratification). This doesn't occur in your vehicle because the electrolyte is sloshed around when driving. When the electrolyte stratifies, some of the layers contain substances (notably sulpher) which have a tendency to leave a coating on the lead plates, reducing their effectiveness and decreasing the battery's capacity. Therefore, most lead-acid battery manufacturers recommend and charge rate sufficient to allow the electrolyte to bubble slightly, thereby agitating the electrolyte and decreasing the potential for stratification.

The rate of charge or discharge of a battery is rated using the letter C and a number. We use this number to determine appropriate charge and discharge rates (as defined by the manufacturer).

So, back to the issue of proper PV (photovoltaic (the solar panels)) for a given battery bank. The accepted rate of charge to provide proper electrolyte activity is C/8-C/12. This means take the rated capacity of the battery bank and divide by between 8 and 12 the that will tell you the amount of PV you need to reach an acceptable charge rate.

Here's an example:
My new system has a battery bank (sized to my needs) of 470ah. meaning it will deliver 470 amps for 1 hour before dying, or 235 for 2 hours, and so forth. Note: we never size battery banks for full discharge, while lead-acid batteries can support a discharge down to 20%, this decreases life considerably, and 50% discharge is considers as far as you'd want to go and keep your batteries happy and long-lived.

If I take my 470 and divide it by 8 I get 58.75 amps, if I divide it by 12 I get 39.16 amps. So to get the longest life from my batteries I will need enough PV to deliver at least 39.16 amps to the battery bank.

So, now I know I need a charge controller that can handle at least 39 amps, and I need an array that can deliver it.

The new crop of charge controller (MPPT) can use a wide array of panel configurations and still convert the watts and volts into the proper amps for changing, provides you have enough panels.

Using ohms law to calculate power and my battery bank being 24V, I calculate that I will need 960 watts of solar panels to reach the C/12 rate of charge. I have 4-250w panels.

I knew nothing about off-grid solar 4 years ago when I started my first system and made quite a few mistakes. While I think anyone can learn how to apply off-grid solar to a more self-sufficient existence, there are two obstacles: 1. Solar is expensive and mistakes made cost money. 2. There is a learning curve involved, and while the calculations require nothing more the addition, subtraction, multiplication, and division, there is quite a bit to learn before actually being able to implement a functional and efficient design.

It all starts will figuring out what you want to power with solar. That is the first number you need before design can begin.

What I quickly learned was that I could not afford to build a system to power everything I wanted it to power. There was my first hard lesson. It's far, far cheaper to conserve and reduce demand for power than it is to produce the power.

The best tool to begin this journey is a little gadget called a kill-o-watt. This plugs into the wall, then you plug your appliance, light, etc into it, and it will tell you how much power it drawing, and also how much power it used over a given period of time. I plugged this into my fridge and freezer to determine how much battery capacity I needed to run them for 3 days without sunshine.

Didn't mean to steal this thread but I absolutely agree that a site dedicated to DIY off-grid solar how to would have helped me when I started.

Thanks for the insight everyone. Lots of really good pointers and questions already. I'm going to get a design for a website up in the next couple of weeks and will post it here.

I'll address some questions very briefly.

1. The future is solar. We are already seeing costs of solar farms rival that of traditional means. In 5-10 years we are going to see the beginning of a massive change in how we view energy. One of the reasons I wanted to put a site like the one I'm proposing together is that costs and availability will go down just as significantly as they have in the past few years. New innovations will be seen with energy storage. With this there will be a surge in demand for off grid solar (my prediction) as the technology becomes cheaper and more accessible.

2. Lots to talk about in the lease vs purchase options. I'll have to address this in detail some other time. Don't be turned off by leasing, they can actually be a pretty good deal.

3. When solar first came around there was a law in which utilities were required to pay for extra power. Lots of utilities have been able to get around this in one way or another. While this is a feasible option for some utilities the return on your investment will take a really long time. I would not explore this option as it really will not be very cost effective. What is readily available and will be for quite awhile are energy credits. You can create excess power in the summer that you don't use and it will be credited to your bill through the winter.

4. Community solar is possible but right now it is not economical. If you want to do some research look up microgrids. This will happen but don't expect it for another 5-10 years as the cost of energy storage comes down. This is a pretty exciting offshoot of solar that I'll be following closely as it progresses.

Thanks for all the feedback everyone. Anything I do put up I'll make sure its quality and easy to understand.

Alex - thanks for the brief answers. I look forward to learning from your website!

Gerard Foret wrote:For Dan (and others):

"When a battery is kept in a stationary position, this continuous rising and falling of it's specific gravity causes the compounds in the electrolyte to somewhat separate into layers (stratification). This doesn't occur in your vehicle because the electrolyte is sloshed around when driving."

- How about a rack for the batteries made of pallets raised up on two or three "rockers" underneath? A 2X6 on edge, tapered at both ends of the bottom surface and nailed/screwed to the underside of the flat pallet rack would allow you to just put your foot on the corner and rock the batteries a bit each day or two to keep the plates free of stratified elements. Simple, cheap, and effective I would think. You could also attach a rope to it, up to a pulley mounted on the ceiling and pass the rope through the wall and then just pull the rope to rock it from the outside as you walk by without entering. Heck, you could even set up a little electric motor with a (probably counterweighted) arm attached to a cam on the drive shaft to rock the bateries on a schedule with a timer switch. The longevity gained would probably offset the energy used, but you'd need to analyze that to be sure.

Alex, if you need some help with drawings let me know, I'm a draftsman by trade, 2d/3d autocad etc.

I would love to see this happen. I have a little experience building my own solar panels for really cheap, out of recycled windows and chipped cells off ebay. I can make a solar panel for fifty bucks, that would cost two to three hundred to buy. But the problem is, I am no electrician, and I have never been able to find that great of information on how to wire everything together to complete the system. It would be great to no all the little specifics that are so hard to find just on youtube.

Dear Sir..... I am so interested. I have a few small pieces of property in the region of Aragon in Spain where I grow olives ,almonds, fruit and veg. I have wanted to use a small solar system for a few years now and have never made the step due to the fact that I just dont know what I am talking about when it comes to this subject. There are so many systems on the market, so many claims. I would love to be part of a forum that talked about the realities of a system as I dislike investing time and money only to find out later that I did not quite get it right.

Wow we really DO need a jargon buster included. I saw Amps, Volts, Ohms and Watts in there and no idea what the difference is. For the website, though. Not here.
Wonderful idea. Wonderful generosity and already an offer of help with drafting. Don't you just love Permies?
Go for it guys. We need this.
Please remember though to include info for us who live in duller, rainier places. Not everyone has long hot summers!!

I would also be interested in how to interest the local utility to set up a soalar farm on our property

Sue

this is a project that i have been planning to do in my retirement years which is about four years from now.
the more info and ideas that this may bring will be very beneficial when it comes time to put it all together.

I suspect rocking the batteries periodically would work and an automated mechanism would help. What keep me attracted to solar is the "no moving parts" approach. My small battery bank (8-6v/235ah batteries) including the housing weighs about 560 lbs. Scaling the charge controller and panels for proper charge rates takes care of the stratification issue without moving parts and has the added benefit of more rapid replenishment of charge. My system recovers from a 50% depth of discharge with 6 hrs of daylight and takes over 4 days without sun to drain to that 50% mark. So, I only need 1 day in 5 with sun to keep things running. I'm also installing a small 300w grid tie to dump any surplus into the house for grid-based usage.

Joe DiMeglio wrote:

Gerard Foret wrote:For Dan (and others):

"When a battery is kept in a stationary position, this continuous rising and falling of it's specific gravity causes the compounds in the electrolyte to somewhat separate into layers (stratification). This doesn't occur in your vehicle because the electrolyte is sloshed around when driving."

- How about a rack for the batteries made of pallets raised up on two or three "rockers" underneath? A 2X6 on edge, tapered at both ends of the bottom surface and nailed/screwed to the underside of the flat pallet rack would allow you to just put your foot on the corner and rock the batteries a bit each day or two to keep the plates free of stratified elements. Simple, cheap, and effective I would think. You could also attach a rope to it, up to a pulley mounted on the ceiling and pass the rope through the wall and then just pull the rope to rock it from the outside as you walk by without entering. Heck, you could even set up a little electric motor with a (probably counterweighted) arm attached to a cam on the drive shaft to rock the bateries on a schedule with a timer switch. The longevity gained would probably offset the energy used, but you'd need to analyze that to be sure.

Robert Curris wrote:Wow we really DO need a jargon buster included. I saw Amps, Volts, Ohms and Watts in there and no idea what the difference is. For the website, though. Not here.
Wonderful idea. Wonderful generosity and already an offer of help with drafting. Don't you just love Permies?
Go for it guys. We need this.
Please remember though to include info for us who live in duller, rainier places. Not everyone has long hot summers!!

I have an electronics background and can help with explaining the electrical jargon in layman's terms.

It would be nice to also remember to include passive solar projects and how to create them. Passive solar is usually pretty cheap to work with and takes some of the strain off of the electrical / gas usage. Some are water heaters, heat sinks, ovens and other cooking devices, window boxes that store heat and can be used as small green houses. I remember so many passive projects that were developed in the late 60's and early 70's that seem to have been forgotten. There are also passive cooling methods that were used in earlier times when air conditioning and electric fans didn't exsist. I would love to see reutilization of past technologies that are less dependant on electrical output.

Tomico

I love this idea. It's definitely a fascinating subject full of mysteries for the average person. Sounds like an excellent resource.

Alex, I've been doing website development for years. If you'd like any help setting up the website, please hit me up. I'd be glad to volunteer my services.

This sounds like such a great project. We have a non grid tied system for the past 8 yrs. It was just 1 kw but we added another 1.4 kw a year ago at 1/3 the price of the original 1 kw! Our installer said he never thought he would see the day when generation would be cheaper than conservation..but that time has come. He no longer sells eco fridges or freezers as a result. He also can't sell wind generators and far fewer hydro units than he used to. The new systems he installs now are commonly 5-10 kw and people are even heating their water electrically ith PV. That's Chinese manufacturing!

Not a point to be flogged, but i hope we try to buy American built panels. i know they are in greater demand than the Chinese, but i prefer to support my neighbors by buying products which support our economy. Got that out of the way.

Many good points made on the grid-tie, vs stand-alone. Personally i'd go stand alone because i am an independent cuss as much as possible.

Something that may be or only seem irrelevant - i know of someone who installed Graphene super capacitors in lieu of batteries. Insanely expensive, but i've heard of people making their own graphene "replacement car batteries" with a computer disk labeling software and a CD with a skin that has Graphite oxide on it to be hit by the lazer to turn it into graphene. Anyone familiar with this? i suspect that composite systems will work in many places - at least outside urban areas.

The traditional is wind/solar, but megametals (probably too pricey if they are even available at all) are converting energy into electricity at PV panel rates. Put the megametal in front of wi-fi, or microwave, or noise (if they are so tuned) and bam - power. i also want to take it a step up and use it for electrolysis to make hydrogen, combine the O2 and Hydrogen in a boiler to make steam and see how THAT works. Heck, for a back up a rocket-stove boiler and peltonen turbines to do runs of steam generated power (alternator to charge batteries?) during power outages for grid tie?

Just throwing things out and they probably landed outside the box. i guess i don't like boxes either, lol.

Good thread here, peeps.

We live in New Zealand and PV panels are not made here. Totally understand the buy local desire.

Sue - my wife works for Real Goods now. They were one of the very first in the US to sell solar and alternative lifestyle system things. Eventually they went corporate. Are now going back to their roots with the original owner buying it back - John Schaeffer.

Right now many, MANY people are demanding US made solar systems, and they object to the Chinese-made Canadian modules. The second choice right now is clearly the Mexico made Kyocera panels.

Most large corporations seem psychopathic to varying degrees, so i try to keep it low on the crazy scale, if you know what i mean. ie if i want a non-GMO seed (& magically i do - ) then i will go with Baker Creek and the way they check their genetics instead of Northrup King who is a Moron-santo subsidiary. kinda like that.

Tomico Revilak wrote:It would be nice to also remember to include passive solar projects and how to create them. Passive solar is usually pretty cheap to work with and takes some of the strain off of the electrical / gas usage. Some are water heaters, heat sinks, ovens and other cooking devices, window boxes that store heat and can be used as small green houses. I remember so many passive projects that were developed in the late 60's and early 70's that seem to have been forgotten. There are also passive cooling methods that were used in earlier times when air conditioning and electric fans didn't exsist. I would love to see reutilization of past technologies that are less dependant on electrical output.

Tomico

While passive solar is more of my thing, I don't think mixing passive with panels is good idea unless you allow the website to have a good fork point and one person to oversee each fork. One fork focused on thermodynamics and the other is electrical/mechanical based model. I'd rather see this stay on PV and if somebody wants to take on the passive side link and share between them.

Tomico, maybe you and I should work on the Passive Solar side of this concept. I can handle some web stuff, definitely have a maker attitude and can draw/draft anything I can see/feel/imagine.

Hi
I want to share this with you BuildItSolar Photovoltaic (PV) Systems. I´m not a Solar PV expert but the information they have on Solar Water Heating is great for DIY people, so I think the material for Solar PV should be good too. (I search, and there are already many good references to this site on permies.com)

Joe DiMeglio wrote:

Gerard Foret wrote:For Dan (and others):

"When a battery is kept in a stationary position, this continuous rising and falling of it's specific gravity causes the compounds in the electrolyte to somewhat separate into layers (stratification). This doesn't occur in your vehicle because the electrolyte is sloshed around when driving."

- How about a rack for the batteries made of pallets raised up on two or three "rockers" underneath? A 2X6 on edge, tapered at both ends of the bottom surface and nailed/screwed to the underside of the flat pallet rack would allow you to just put your foot on the corner and rock the batteries a bit each day or two to keep the plates free of stratified elements. Simple, cheap, and effective I would think. You could also attach a rope to it, up to a pulley mounted on the ceiling and pass the rope through the wall and then just pull the rope to rock it from the outside as you walk by without entering. Heck, you could even set up a little electric motor with a (probably counterweighted) arm attached to a cam on the drive shaft to rock the bateries on a schedule with a timer switch. The longevity gained would probably offset the energy used, but you'd need to analyze that to be sure.

Joe - this could possibly work. One of the things to keep in mind is the weight of the lead acid batteries. You will need to have a very sturdy rack in order to withstand shaking or jostling.

Hey
i love this Idea for DIY ers
it might even have some overlap with the Emergency Energy Battery Backup Videos recommended earlier by Paul for the electricity illiterate.
I Agree that from a Permie standpoint all avenues of passive solar should be included and preferred.
and i too have been leaning toward grid tie-in option
Also I can relate to those who don't have a limitless supply of sun. and because of this would like to develop a hybrid wind solar generating system.
Just one last thing;
One of the reasons I'm not crazy about solar is the finite life span of solar panels. or have they developed past that limitation?

I love this idea. I'm very interested in this subject but very little knowledge. Thank you, I'm very excited about what's coming.

YES YES...need this resource!
I have no clue about what is a watt, Ohm or anything but want to get off the grid.
Would be interested in making solar panels as it is much cheaper I've heard.
No clue on how to do it.
No one seemd to be addressing theproblem when the batteries wear out.
What happens to all that acid that is inside?
Can the batteries be "rehabbed"? Or do they need to get dumped at some point?
Just saw something about making electricity with wood?
Would this be any better? Could have a big wood lot with sustainaboe wood growing and ise that as it recycles itself.
Anyone know anything about wood to make electricity?

Karen,
Lead-acid batteries are extremely recyleable (>80%). The acid is easily neutralized (although will typically neutralize itself over time) and over 50% of the lead supply comes from recycled batteries. Battery replacement/management thru recycling is an inherent part of off-grid solar ownership. Depending on the battery choice, well cared for battery banks last between 5-15 years. One exception is Nickel-Iron batteries. Very expensive but come with a 10 year warranty and some installed 80 years ago still work.

Wood for electricity presents a few problems mostly having to do with energy conversion. You'd either be burning the wood to produce stream to spin a turbine to turn a generator, or heating wood to create wood-gas, to run a generator. Both involve several energy conversion transfers, each reducing efficiency. Most consider wood to be a resource for producing heat, and as a construction material. Specifically when used for heat, hardwoods are chosen which are slow growth trees. Rocket mass heaters have been proven to be the most efficient currently available approach to heating a space with wood.

Solar Panels over their lifetime produce 7 times the amount of energy that went into their manufacture. The also have less than 30% of the carbon footprint of fossil-fuel electrical production.

With current panel prices right below $1/watt, a DIYer would be hard pressed to make their own panels with the same durability and output as commercial panels for less than $1/watt.

The first step in migrating to off-grid power is to understand your current power usage. A rule-of-thumb is to take your current monthly electric bill, multiply it by 260 and that's what you'd have to spend on an off-grid solar package to live the same way you live now. Additionally, take 20% of than number and you'll be spending that on battery replacement every 5-8 years. Most of us who grew up with cheap power (and electricity from power companies is VERY cheap compared to having to make it yourself) have had to slowly change how we live to reduce our electrical usage. If my monthly electric bill is $150, I'd have to spend $39,000 for off-grid solar. If I can change the way I live and reduce that to $75/month, I'd only have to spend $19,500. This is a ballpark estimate but I think it's pretty close.

Once I started looking at power this way, I have begun looking for places where I either waste power, or can use an alternative energy source. As an example, I now burn wood in a buck stove for most of my heat. I harvest some wood, and purchase some as well. Over the 3 years I've been doing this I have reduced my electrical bills in the winter by $50-$100/month. On average I've been spending $200/year on wood, and saving $400-500/year on my electrical usage. I've also gotten the benefit of physical activity (cutting, splitting, and hauling firewood is physical), and we know that should we lose power, we have a reliable source of heat. In the summer, I do most of my cooking and canning outdoors on our deck using propane. The propane is costs me about the same as if I was using the electric stove, but keeps the heat outdoors, reducing the load on the air conditioner. In the winter, it's the opposite. I do the cooking indoors and function stack the heat used for cooking to help heat the house.

My approach has been to go small scale, and pick specific applications to use with off-grid solar. My horse barn is 300' from my house and when the power line between my house and barn failed, it was the same price for me to install solar on the barn, rather than replace the cable. The system I'm currently installing will run my freezer and fridge completely off-grid and also give me a little extra (such as run my indoor aquaponics system pumps.)

Karen Crane wrote:YES YES...need this resource!
I have no clue about what is a watt, Ohm or anything but want to get off the grid.
Would be interested in making solar panels as it is much cheaper I've heard.
No clue on how to do it.
No one seemd to be addressing theproblem when the batteries wear out.
What happens to all that acid that is inside?
Can the batteries be "rehabbed"? Or do they need to get dumped at some point?
Just saw something about making electricity with wood?
Would this be any better? Could have a big wood lot with sustainaboe wood growing and ise that as it recycles itself.
Anyone know anything about wood to make electricity?

Thanks for your help.
According to your cost estimate, it would
cost me over $10,000 to put in solar.
Good grief! That is with a low income reduced rate.
If I had to use the full "value" of what with bill would be
without the low income recuction it would probably be over $20,000!
Sorry don't have that kind of money!
Yes, I understand, lessen the electrical load.
Looking at what I woud want to get rid of.....
definately need to keep the water/well pump.... fridge
and if I end up getting one, possibly the freezer.
some lights. ,,,, really want to be able to use the computer
and right now need an internet phone as there is no land lines here.
That would only eliminate the TV which I guess I could get on the internet
but again that would take moe power. ug.
I have read about people who have it all with solar and now hate
to think what i costs them to do it.
Where I am and with the money I havek it is cheaper to stay on the grid.
Is there a way to have both?
When there is no power, I would want the well pump to still work along with the fridge.

http://www.sunrnr.com/Products-Pricing.html


I have great sympathy with the above comment. I have been learning to monitor better.
Can anyone tell me if the product in the link is a good buy, or does it just seem so to me at this time.
I like the idea that one could disconnect from the panels, take it out to the field and use as you would a gas powered generator, return and recharge. Hopeful Fantasy or not?

There's a guy with a YouTube channel called "engineer775" who uses one. In fact, I saw him testing it with a bicycle-powered generator in this video: http://youtu.be/cWk7TgxKpo0?list=UUpDl4WPpgvvOeZFpw4ewycA

You might want to reach out to him for details on the unit.

That's exactly how my project started. I wanted backup for my fridge and freezer in case of a power outage. After designing to the capacity I needed, I realized that I could use it all the time, not just when power was out.

Depending on the size and power requirements of the well pump you may be able to make it work. The system I'm putting in to run my fridge (which is the real power pig) and freezer is costing me right at $3,000 and I'm doing the install myself.

Karen Crane wrote:
Is there a way to have both?
When there is no power, I would want the well pump to still work along with the fridge.

Joe DiMeglio wrote:How about a rack for the batteries made of pallets raised up on two or three "rockers" underneath? A 2X6 on edge, tapered at both ends of the bottom surface and nailed/screwed to the underside of the flat pallet rack would allow you to just put your foot on the corner and rock the batteries a bit each day or two to keep the plates free of stratified elements.

A couple of problems with that:
1.) It won't help
2.) It will only work for a fairly small battery bank.

Addressing number 2 first: Our battery bank weighs 3.08 tons with the cells full of electrolyte. And that's only 16 batteries. It takes two men and a hand cart to move one battery. Our batteries have not been moved since they were installed 7 years ago, and they will not be moved until they are replaced. Putting them on anything but a solid concrete floor would be dangerous beyond belief (and no, it does NOT hurt batteries to set on a concrete floor in your power room).

Addressing number 1: Stirring the electrolyte in tall cell batteries such as ours, and keeping the grids properly desulfated is accomplished by the charging process, not shaking them. And it takes a long time of inactivity to stratify even tall cell batteries. Our batteries get ~70 cycles per year on them (our cycle length between full charges averages about once every 5 days). We have run 2 week long cycles many, many times in the winter and never had any problems at all with stratification. Stratification is not a mysterious thing - the more dense electrolyte settles to the bottom of a tall cell and water collects on top. It is easily dectectable with a hydrometer. But in a real off-grid installation where the batteries are never at rest the battery is undergoing constant chemical reactions, either charging or discharging, and they will never stratify as long as they are active. They will hard sulfate if not properly charged, but that is a different issue.

Gerard, thank you for your sage response. I believe you gave me a great starting point in terms of what type of system to design and all the considerations that follow. A system to run food storage/water supply to protect oneself in case of a power outage. I would imagine that DIYers would want to start small to gain an in-depth understanding before tackling a very pricey system that would offset their entire energy usage.

Gerard Foret wrote:That's exactly how my project started. I wanted backup for my fridge and freezer in case of a power outage. After designing to the capacity I needed, I realized that I could use it all the time, not just when power was out.

Depending on the size and power requirements of the well pump you may be able to make it work. The system I'm putting in to run my fridge (which is the real power pig) and freezer is costing me right at $3,000 and I'm doing the install myself.

Karen Crane wrote:
Is there a way to have both?
When there is no power, I would want the well pump to still work along with the fridge.

Above comment quite interesting. It was a clear description based on experience.
If you have the time would like to hear more of your experience, what you have come to realize and what you might do different.
Or even your advice to someone who was on a budget, would like to start ,who had plenty of sun and ideally would like 6kw but would be happy with 3kw.

Karen Crane wrote:
Where I am and with the money I havek it is cheaper to stay on the grid.
Is there a way to have both?

Karen, if somebody comes along and claims the cost of solar power can match utility power, they are blowin' smoke and pushing bogus numbers. The one and only thing that makes grid-tied solar power systems cost effective is government subsidies, rebates, tax incentives or FIT (Feed In Tariff) programs.

For anybody with utility power that wants backup power, a small generator that costs less than $1,000 will do more in a power outage than $10,000 worth of solar panels. For anybody that lives off-grid full time, the generator is the most important power producing unit you have - NOT the solar panels, or wind turbines or micro-hydro. The solar panels, wind turbines and hydro generators work at the mercy of Mother Nature. The generator is the one and only thing you can count on. One of the necessary evils of off-grid living is batteries. You need the generator to take care of them for a full-time off-grid home because you can spend $20,000 on solar panels and they still can't take care of your loads and battery bank with 100% reliability.

The fact is that those of us who live off-grid year 'round - and especially up here in the north where we get 200" of snow and it gets to -40 in the winter time - live with VERY expensive power compared to anyone who has utility power. Applying what we have to the everyday needs of someone with grid power is just plain senseless because there is too many pitfalls with solar power (although you'll get a more rosy story from solar installers).