# D-I-Y "Solar Generator" for less than $500



## LincTex

I can't believe the systems folks are trying to sell for two grand!

Here is a simple way to build your own "Solar Generator".

Yep. It is NOT hard to build. You will need good batteries, though. ANY battery worth its salt (in storage capacity, which is VERY important) will be VERY heavy, except the Odyssey, but that will likely drive you over 500 because they are so expensive. You might need help handling the battery/batteries.

You will need to make a have a small place in a room on the south wall of your house to store the battery(ies), no cart needed or even suggested here.
There is nothing difficult about the wiring, either.

Buy this: $200 http://www.ebay.com/itm/Brand-New-1...8103304?pt=LH_DefaultDomain_0&hash=item3f1e1c 2f88

Biggest Marine deep-cycle you can find: $100 (Walmart/Sams). If you can afford it, get two 6-volt "golf cart" batteries instead.

20 or 30 amp charge controller $10-$50 http://www.ebay.com/itm/20A-12V-24V...9734938?pt=LH_DefaultDomain_0&hash=item1e7019 731a

http://www.ebay.com/itm/20A-Solar-C...8852494?pt=LH_DefaultDomain_0&hash=item19d642 500e

http://www.ebay.com/itm/30A-PWM-12-...6946324?pt=LH_DefaultDomain_0&hash=item4d063a 0094

http://www.ebay.com/itm/10A-20A-30A...6252817?pt=LH_DefaultDomain_0&var=&hash=item1 c272b9891

Ok, we're up to $350.
That leaves $150 left to get a decent inverter.

Harbor Freight sells a good one that goes on sale OFTEN for $129, I think it is 2000 watt run/4000 watt peak. I have one of those big monsters but never used it (I got it for Christmas) and it gets good reviews online.

My "go to" inverter is a (I *think*) 800 watt run/1600 watt peak (no longer made).... I would have to go look to see what it is... I have had it for about 10 years or so. No complaints with it ever. However, the biggest thing I have ever run from it is some construction power tools like a "Skil saw" and such. I think they replaced it with one a little bigger, at 1000 watt run/2000 watt peak.

The 1000/2000 is on sale for $79, but i see $59 on this one with a coupon often http://www.harborfreight.com/automo...uous-2000-watt-peak-power-inverter-97047.html

They also have a 750/1500 for $49, I would also imagine it will go to $39 or $29 with a coupon. http://www.harborfreight.com/automo...nuous1500-watt-peak-power-inverter-69660.html

Never buy anything from Harbor Freight without a coupon. They regularly sell stuff 50%-80% off with a coupon. My Sunday paper comes with the best coupons ever (we have a local HF store).

ONE THING is to always get the biggest inverter you can ever imagine needing. The more you push it towards its max power rating, the hotter it will get, and that isn't good.

Assembling it is as easy as being able to tell red from black:









If you want more than one battery (and I highly recommend you do, if this is a plan you want to put in place) then use this diagram for four "golf cart" batteries. If you want TWO, just "erase the bottom pair" and their wires. Yes, That Easy!


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## Tirediron

Great idea, if you build it you can fix it, another thought is a couple of small inverters to run light loads, built in redundancy


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## LincTex

Tirediron said:


> another thought is a couple of small inverters to run light loads, built in redundancy


Yep, spare inverters always on hand... lots of times can be found as "FREE" in the form of old UPS units people toss because the internal batteries are bad!


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## goshengirl

Okay, I'm showing this to my husband! Thank you!


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## DJgang

goshengirl said:


> Okay, I'm showing this to my husband! Thank you!


Me too. Maybe he will do something.


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## Grimm

DJgang said:


> Me too. Maybe he will do something.


Me three!


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## LincTex

I also need to mention that many inverters use "alligator clips" on the included wiring to attach to the battery... these work OK for light loads, but you often will NOT get full rated capacity out of your inverter unless you remove the clips and attach crimp-on ring terminals onto your black and red wires instead. 

Inverters need "amperage" (current flow) to give output, and the places where alligator clips attach to the battery have a very small area of contact = very little flow. 
It is like "standing on the garden hose"!


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## hiwall

Thanks for posting this Linc. I'm already set up but I know many people think you need an engineers degree to make your own. And the ones you see advertised sell for $1500 to $2000. They don't realize that you only need 4 pieces!!


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## MetalPrepper

Definantly showing this to husband, I was going to buy him something to start this with for Christmas....amybe an inverter?


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## pawpaw

LincTex said:


> Yep, spare inverters always on hand... lots of times can be found as "FREE" in the form of old UPS units people toss because the internal batteries are bad!


What's a 'UPS' unit?


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## Tirediron

UPS in this case is uninterupted power supply, often sold to provide computer users time to back up and shutdown if grid power fails or drops out


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## pawpaw

Sorry. I wasn't familiar with the acronim. I'm even the one who posted about a new site I found interesting- "Low Tech Magazine". My computer is faster than me, and it's Windows '98. _*1898! *_


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## nomadjanet

Thanks for this post. My husband is very handy but he is a non prepper so I have been wanting something I could do myself. I think I could handle this. Thanks again.


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## nomadjanet

*book mark thread so I can print the diagram*



nomadjanet said:


> Thanks for this post. My husband is very handy but he is a non prepper so I have been wanting something I could do myself. I think I could handle this. Thanks again.


print this


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## professor

Thanks so much for posting this - my mom was considering buying one of those 2000 dollar ones - but I think I could actually bold this myself.


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## LincTex

http://en.wikipedia.org/wiki/Uninterruptible_power_supply

An old UPS is not design for continuous use...Usually long enough to save your files and shut your computer down.

If you need to run a blender for 5 minutes or a small TV for an hour, I think It could handle it easily. Maybe even a small deep-freezer (they are pretty low amperage draw). I have several old UPS's but haven't played with them enough with "heavy loads" to see how they can handle it.

Inverters have small internal cooling fans to take the heat away, UPS's usually have no internal fan. But you could add one... or two or three. Junk computers have fans that can be robbed easily (and for free) to serve this purpose.


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## Woody

Excellent diagrams! I’ve been toying with something like this and might have the funds soon to at least buy the parts. I’ve done some reading but it is all above me. Your schematic puts in a simple enough way so even I can understand it!

Couple questions though.

What gauge wire is needed from the panel to the batteries? Between the batteries? From the batteries to the load(s)? I remember reading that the farther away the batteries are from the panel the larger the gauge required.

Is there a limit to how many battery banks can be hooked up in series like the lower diagram? I am not thinking so much of load but duration of charge.

If I added another panel or three would I just need to get a different regulator to handle them or can they take multiple panels already?

Thank you again for this post!


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## cowboyhermit

It seems companies are able to charge ridiculous prices for anything involving solar "systems", though the components are very reasonable and so easy to work with. It is the same with solar fence energizers and solar water pumping systems. They are buying off the shelf parts and slapping them together (like in a plastic tool box or rubbermade tub), then charging huge markups. If people are willing to pay that's fine, we all need to make a living. This stuff is really easy and you can save huge amounts of money, not to mention getting something suited to your particular needs.
Only thing I would add is that although I agree it is best to get the biggest inverter you could need it is worth mentioning that bigger inverters generally use more power when supplying small loads. It might be good therefor to get a big inverter first that could be turned on or off when needed and a smaller one, perhaps even sine wave for small loads.
It is better to use dc directly if possible as well so you might want to add at least a cigarette lighter plug or two for using car chargers, or thermoelectric coolers, etc.


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## hiwall

Woody, the answers to your questions are "it depends". Linc suggested a 120 watt panel at 12 volts it equals 10 amps so he suggested a 20 or 30 amp controller. If you bought another 120 watt panel and had a 30 amp controller you would be OK Might be OK with a 20 but safer with a 30. Watts divided by volts equals amps. 16 gauge wire for 10 amps, 14 gauge wire for 15 amps, 12 gauge wire for 20 amps, 10 gauge wire for 30 amps, 8 ga/40 amp, 6 ga/50 amp. Long wire runs might need to step up one wire size but how far you going? You can connect up several batteries and/or use bigger batteries.


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## LincTex

Hiwall, good answers.

Woody, a couple things.

1) You can use the wire sizes hiwall suggested for short runs, but a size larger doesn't hurt, and will have less resistance. That isn't so important on short runs, but the further away components are from each other, the larger the wire size needs to become to compensate for the resistance that increases over distance. The best scenario would be to have your solar panels, charge controller and batteries all very close to each other to minimize the amount of DC voltage wire length. The AC power coming out of the inverter isn't as sensitive to length as the DC side.

2) Add as many batteries as needed to size your system appropriately. It is best to make groups or clusters of batteries, so you can take a group out without disturbing the rest of the system for maintenance. Each group or cluster will need to be equalize occasionally so they charge properly. Read about it here: http://otherpower.com/otherpower_battery_care.html
As you add batteries, you will need either more solar panels to keep them charged (if you are a heavy energy user) or use power less often so they can "catch up".

Yes, Cowboy, using the right size inverter for the job is helpful. Even better is to use the 12 volt power directly, especially lighting because so many good lights are now available that are 12 volts.


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## Woody

Thank you gentlemen for the wire sizes.

I was thinking of keeping the batteries as close to the panels as possible. Each foot of copper wire is expensive to start off with!!! The long runs will be from the batteries to the load.

I am planning on keeping everything 12 volt. It will be lighting and fans for moving air around. Maybe I can talk Santa into a little 12 volt refrigerator as a luxury item. Eventually it would be nice to size it for the well pump but that draws a lot of juice initially and would make for a costly system. That was covered in a thread a while ago. Perhaps I can gradually build up to that point.

I like the idea of having a few different banks of batteries. With a few switches I can keep all banks charged and ready for an emergency. That link answered all the other maintenance questions I had, thanks!


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## LincTex

hiwall said:


> Linc suggested a 120 watt panel at 12 volts it equals 10 amps so he suggested a 20 or 30 amp controller. If you bought another 120 watt panel and had a 30 amp controller you would be OK Might be OK with a 20 but safer with a 30.


It seems most all charge controllers are now made in China, even the relatively expensive Trace/Xantrex series. The inexpensive 10 amp charge controllers will only handle the full 10 amps on a cold day, LOL! (I am speculating here) ...just by what I have seen by looking inside one. I suspect they won't handle 10 amps for extended periods on hot days. Having a controller rated for higher amps gives you some safety factor.

I am believe the "solar generators" being marketed have no charge controller at all... NONE. Just the panel wired straight to the battery pack.

Volts x amps = watts, so be careful of how panel makers rate their panels. Harbor Freight panels rate theirs at "open circuit voltage" (no load applied) which comes in at around 22.5 volts x 2 amps = 45 watts. That's not a lot when actually charging the battery bank.


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## cowboyhermit

My understanding is that it is perfectly fine to not use a charge controller as long as you are only charging at 1/100 C, basically that means it will take 100 hours to charge your battery bank, not exactly what most people are after. Maybe if it was purely a backup and only for short term or very intermittent use or if you could afford a vastly oversize battery bank. The little dashboard panels that keep a car battery from going dead work on this principle. When you get anywhere near 1/10 C, so that it would take 10 hours to charge you are going to shorten the life of your batteries considerably unless you happen to draw them down and keep them from overcharging (boiling) every time.
Another reason a charge controller is worth it is for the low voltage disconnect. Batteries should not be drained completely if you want them to last and a low voltage disconnect can help a lot.
As mentioned before I would stick with 12V for any small system because of the availability of stuff that runs on it. The solar industry in general (larger scale) is all going to higher voltage to minimize line losses but the benefits of common parts and safer voltage are too appealing imho.
Depending on you where you are at there may be ways to get wire for cheap or free, think of how many appliances get thrown away every day, heck an electric stove or dryer has a nice chunk of wire just waiting to be snipped or an old pair of booster cables with rusty clamps. It is also possible to run multiple wires of the same size to make a larger one. Care must be taken to keep them the same length and all connections solid.


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## LincTex

cowboyhermit said:


> Depending on you where you are at there may be ways to get wire for cheap or free, think of how many appliances get thrown away every day, heck an electric stove or dryer has a nice chunk of wire just waiting to be snipped or an old pair of booster cables with rusty clamps. It is also possible to run multiple wires of the same size to make a larger one.


Solid advise! I recycle wire like CRAZY! Any old house being torn down, and I always strip all the wiring out from old cars.

The starter on my Cummins diesel is wired with salvaged 4 and 8-gauge wire. GASP! Yep, sure it... but a several of them, in a bundle, LOL! Since I work in aerospace all the wire and crimp lugs are mil-spec, but salvaged from scrap.


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## Woody

By chatting at the dog park I found a guy who used to install alarm systems in commercial buildings. He says he has 500’ and 1,000’ rolls of 18/2, 16/2, 14/2 and 12/2 wire in both solid and strand. Not romex with a ground but like speaker wire, shielded and with a covering. We talked about solar and he offered to sell a roll of the 14/2 - 1,000’ for $75. Not free but a great deal from what I looked up prices for it. He said it would be perfect for a 12 volt solar application. I am going to his storage locker tomorrow to pick it up and he said he thought he might have some other things I might be interested in. I’m thinking I should check into a roll of the 12 gauge also, just to have it on hand if the price is right. Heck, the price seems almost at scrap copper price if I strip it.


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## LincTex

I never scrap wire with good insulation on it. I can ALWAYS find someone who will pay more than scrap price!


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## jsriley5

cool deal get all that coper much rather store coper in that form than those silly ingots and copper is definitely getting to the price to be considered a precious metal in my book. I was just recently shopping for copper wire myself that is a good price. Get it all at worst you could sell some here


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## zombieresponder

Woody said:


> By chatting at the dog park I found a guy who used to install alarm systems in commercial buildings. He says he has 500' and 1,000' rolls of 18/2, 16/2, 14/2 and 12/2 wire in both solid and strand. Not romex with a ground but like speaker wire, shielded and with a covering. We talked about solar and he offered to sell a roll of the 14/2 - 1,000' for $75. Not free but a great deal from what I looked up prices for it. He said it would be perfect for a 12 volt solar application. I am going to his storage locker tomorrow to pick it up and he said he thought he might have some other things I might be interested in. I'm thinking I should check into a roll of the 12 gauge also, just to have it on hand if the price is right. Heck, the price seems almost at scrap copper price if I strip it.


You want stranded wire from the panels to the controller, and if it's not much amperage and a short run, you can get away with small stranded wire between the controller and the batteries. Between the batteries, and from the batteries to the inverter, you're going to need something more like stranded 10 AWG or larger, it really depends on the size of the inverter though. You want as little voltage drop as possible to maximize the amount of energy getting to the controller and the batteries, as well as from the batteries to the inverter. When voltage drops, amperage draw increases and more heat is created, which then creates more voltage drop, amperage draw, and more heat...and it keeps going until there is either a fire or something fails.

Here is a voltage drop calculator: http://www.supercircuits.com/resources/tools/voltageDrop

There are also some that output a chart based on wire size and amperage draw. If in doubt, go bigger on wire size. It costs more, but it will have less drop. Also, lots of PV systems are now in the 36 or 48 volt range to minimize power loss in the lines to the controller/batteries.


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## Drew86

pawpaw said:


> What's a 'UPS' unit?


Uninterrupted power source


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## LincTex

I should also mention that to those that are getting started in electricity that wire size is always determined by amperage in the circuit.

Volts x amps = watts

Volts is the pressure, or the push
Amps is the flow (small hose, large hose)
Watts is the amount of work being done (small load, large load)

That is how high tension power lines can supply an entire city with wire the size of your index finger. They use very high voltage at low amperage to get the same amount of watts through. Once it gets where it needs to be (substation, transformer at your house) the voltage gets reduced and the amperage goes up, but the watts stay the same.

This is the reason for *needing* the large wire size between the battery and the inverter. A 1200 watt load, like a large electric drill or saw, will draw 10 amps at 120 volts. This is easily handled with a 14 or 16 gauge extension cord.

BUT, the battery side of the inverter, at 12 volts, will draw *100 amps* to make the same 1200 watts needed! You would need at least 8 gauge wire on a very short run (6 gauge would be better, 4 gauge is BEST). It never hurts to go a size larger on the wire, to be safe (and improve efficiency)


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## tugboats

LincTex,

Thankyou for the K.I.S.S. explaination. It was very helpful. You have boiled out all of the vodoo and left just the essence of the system. We are just beginning to get a decent system for the house and you have made our decisions easier.

Tugs


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## LincTex

tugboats said:


> We are just beginning to get a decent system for the house and you have made our decisions easier.


You are welcome, but all that read this please be aware this is a "smaller" sized system to handle some pretty basic loads to make life a lot easier (preparing meals, lighting at night, entertainment, fans) than no power at all.

It isn't a "whole house" sized system by any means, and won't run a water heater, clothes dryer or central heat/air at all.


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## Woody

I understand the need for larger wire from the panels to the controller. I do not know how long the runs there will be yet so am holding off on that expense. This wire is for making runs to the loads. I did end up getting 2 – 1,000’ rolls of solid 14/2, 1 – 1,000’ roll of solid 12/2, 2 – 500’ rolls of 12/2 direct burial for $300. He threw in two of the emergency strobe lights with sirens on them. He said the lights are a huge load but I might be able to use just the siren. He had a pile of 600 (or maybe 500) watt UPS supplies but after talking with him did not get any. Regardless, it is a great start to building enough supplies to get something rolling. I just need to keep my ears open for the rest of the stuff.

Thank you again for a clearer picture of how it all goes together!


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## LincTex

Woody said:


> This wire is for making runs to the loads. I did end up getting 2 - 1,000' rolls of solid 14/2, 1 - 1,000' roll of solid 12/2, 2 - 500' rolls of 12/2 direct burial for $300.


YOU SHOULD be in JAIL! 
4000 feet for $300!!!!!!!!!!!!!!!! Thief!!!!  



LincTex said:


> ...just by what I have seen by looking inside one. I suspect they won't handle 10 amps for extended periods on hot days. Having a controller rated for higher amps gives you some safety factor.


I had typed a longer post on the subject, then the power failed. I have a couple of small charge controllers from a non-profit org call Green Energies, LLC. http://greenenergiesllc.com/zencart/index.php?main_page=product_info&cPath=2&products_id=1

This little charge controller looks like it will handle 15 amps easily (VERY well made) It is all steel (no plastic) built like a tank, made in the USA and is only $20!!!


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## bigdadvrod

pawpaw said:


> What's a 'UPS' unit?


Uninteruppted power supply..used for computers in case of power failure; you have time to shut down your system before you lose data.


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## Viking

LincTex really knows what he's doing here, I would only add a few things to consider. As to solar panels I always try to get the highest cell count I can, for example for a 12 volt system panels are frequently found with 32 and 36 cells per panel. The panels I used on our motor home are 44 cell per panel but sorry to say the supplier no longer sells those panels as they claim RV's have gotten smaller and so people are looking for smaller panels. No matter where one gets panels the thing that you should know is that cell count makes a difference in the efficiency of a system. 32 cell panels produce about 17+ volts, 36 cell panels produce 18+ volts and the 44 cell panel puts out 21+ volts, of course these figures are with full sun. Thin clouds, haze,or smoke in the air reduce available sun and panels will be lower in their outputs. The other factor is solar time, summer verses winter months. A good MPPT (Maximum Power Point Tracking) solar controller can use the higher cell count panel voltages to charge batteries even on a not so good sun day. Yeah, I know, I'm adding to the cost but I thought I'd just add my two cents worth into the equation. One other thing in consideration is I always use the largest size wires I can, especially on 6 volt golf cart batteries as they have very high amperage capabilities. With the four series/ parallel 225 amp hour batteries I'm using the wires are #4/0 ga. even though #1/0 is recommended, that way there is no resistance loss from the batteries to the inverter. My inverter is a heavy duty 2000 watt unit but for smaller inverters you wouldn't need that heavy of wires though it doesn't hurt to use the largest you can.


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## dahur

I've been thinking about trying something similar utilizing my golf cart's 36v bank. The six t-105's have 48 kw of storage, usable maybe about 20 kw. 
Putting in a sub panel with a few circuits. Then finding an inverter with a 36v input, preferably pure sine wave.


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## LincTex

dahur said:


> I've been thinking about trying something similar utilizing my golf cart's 36v bank.


Take pictures of how its wired. Keep for ref. You can always go back to that connection scheme.

Now go buy some terminated jumper wires so you can reconnect the batteries in 24 volts so that you can use a more common inverter


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## mosquitomountainman

I just did a quick article on the effect of shade on solar output. You can see it at Susan's_ Poverty Prepping Blog_ at:

http://povertyprepping.blogspot.com/


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## LincTex

mosquitomountainman said:


> I just did a quick article on the effect of shade on solar output.
> http://povertyprepping.blogspot.com/


Fascinating!


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## cnsper

Another thing is to keep your DC wire runs as short as possible to reduce loss due to resistance.

Also think about going to higher DC voltages. There are 24, 36 and 48 volt versions available also. I have a lot of experience with phone systems and 48v power plants for them and I can tell you that you can run for a VERY long time with fewer batteries on 48v than you can on 12v.


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## cowboyhermit

With properly designed systems the efficiency difference between 12V DC and 48V DC should be negligible at most. 
The proliferation of 12V components out weights the potential advantage in any system I have setup.
I really don't mean to disregard your experience cnsper, I just think something must be wrong in the setup. 
I have converted systems from 12V to 24V and to 48V (not by my choice), and put some back on 12V and there was no measurable difference except for cheaper and more variety of parts in 12V.


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## LincTex

cowboyhermit said:


> With properly designed systems the efficiency difference between 12V DC and 48V DC should be negligible at most.


I think depends on the scale. If THSHTF, I am not trying to power the entire house like some people are doing (especially off-gridders). If you are off grid and want a home with all modern conveniences, then I can see a well-thought-out 48 volt system doing that more easily than a 12 volt system.

Most folks on this message board are wanting to power some basic items, like some lights, a TV or blender/mixer. That would be me. You can do a LOT with a 800-1000-1500 watt inverter and some 12 volt batteries. I know I can build an entire house, because I have done it. Powering a machine shop (or any major appliance) takes far more capacity, and for those situations a person really needs to evaluate their needs.


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## cowboyhermit

Sorry for harping on this so much, just one of those things that I have been involved in and seen people regret and it can be an expensive mistake. 
For a 48V system for example there is the benefit of easier DC cable runs but to what, very few things will run at that voltage, telecommunications equipment, fans, some circuit boards or power over Ethernet equipment.
Almost everything else will need to be powered off of AC, making the voltage loss advantages moot.
A 48V inverter MAY be more efficient than a 12V one, depending on the model. With high quality components it is not significant imo. You can go to the local hardware store and pick up a 12V 3000watt inverter that will handle most anything but if you need more you can just add another.
I have worked on what I would consider large systems and my experience has been that higher voltage is not worth it.
Again I apologize LincTex for going off in your thread.


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## LincTex

cowboyhermit said:


> Again I apologize LincTex for going off in your thread.


I think there is some relevance, some folks would inevitably start thinking "larger" after beginning with a basic, simple system.


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## Viking

dahur said:


> I've been thinking about trying something similar utilizing my golf cart's 36v bank. The six t-105's have 48 kw of storage, usable maybe about 20 kw.
> Putting in a sub panel with a few circuits. Then finding an inverter with a 36v input, preferably pure sine wave.


The inverter-charger we bought is a Magnum Energy MS 4024 PAE model pure sine that runs on 24 volts and puts out 120/240 VAC split phase at a 4000 watt rating. The next size is a 4400 watt unit that runs on 48 volts. Either one can be parallel stacked for up to 17.6 kw. Xantrex makes pure sine inverter-chargers that can be put series for 120/240 VAC or stacked parallel for greater wattage. They come in 2000 and 3000 watt units and operate on 12 volts. I thought about using the 12 volt Xantrex inverters but I wanted 120/240 without having to buy two expensive units and that's why we went with the Magnum Energy inverter. The system I designed is mainly for supplying emergency power for two refrigerators, one freezer and a little bit of lighting, the rest of our home will be grid electricity. Well here I am looking at the thread title and just realized I'm totally highjacking a simple low cost system with an expensive idea, sorry.


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## LincTex

Viking said:


> Well here I am looking at the thread title and just realized I'm totally highjacking a simple low cost system with an expensive idea, sorry.


Haha! Bringing it "to the top" with every new post, LOL!


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## mpguy18

This thread is very intersting - especially for us that know very little and are absorbing this like a sponge. 

With that said, where would we start our learning on the subject that is concise, functional and relevent to this line of thinking? I was a general contractor for years, and was familiar with electrical hookups, loads, etc., but what is being brought to the table in this thread is far more detailed, indepth and practicle. Does anyone know a site, or have docs that would give a fast ramp up to obtaining the knowledge necessary to work with this? Have been knocked on my butt too many times with electricy to know that if I don't know exactly what I'm doing, hold off until I do. 

Sorry to sideline the thread, but think it will be of benefit to many that are reading. Thanks all.


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## Viking

Don't feel alone on this solar knowledge stuff because in the few short years since I installed the solar system on the motor home there has been some changes. New to me is the use of MC-4 connectors. The 100 watt panels I installed had junction boxes with screw terminals for wiring. As to learning about solar wiring if I need info I go to the Start Page search and type in Solar System Wiring, I just checked it out a few minutes ago and there is a lot of good info from various sites.


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## hiwall

I just finished pulling the working 3-way RV refrigerator out of my RV and replaced it with a standard 120 volt electric. Now I can run the refrig for "free" with solar.


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## cowboyhermit

The solar companies have been pushing the connectors for years but you can still get panels with junction boxes which personally I MUCH prefer. The ones with junction boxes are typically for lower voltage systems. The mc-4 should never be unplugged with current flowing due to arcing.

I wish I could give a particular site for good info but am just not aware of a specific one. If you are working with a low voltage dc system it is really no different than automotive wiring. Low voltage wiring such as welding, automotive, and trailer wire can be used safely. There are plenty of wire size calculators online that work with DC.http://www.engineeringtoolbox.com/amps-wire-gauge-d_730.html
http://www.freesunpower.com/wire_calc.php
When I come across a new situation with wiring, which isn't too often anymore I usually just calculate it from scratch to avoid any problems.
The big retailers tend to have solid info thoughhttp://www.solar-electric.com/soinandfa.html
Good Luck for anyone trying solar power we have been using it to some degree for many years and are loving it more all the time.


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## Recon911

PawPaw,
A UPS is what we call here in Hawaii as a APC UPS ES Back-up Power Supply Plus Surge Protection. It usually has a 7 A/h 12 volt battery for the back up. It protects against power surges,of course and brown outs,which is when your AC power dips below 95 VAC and damage to appliances if they are on or running.
I have two of these set up my home here in Hawaii because has a very long history of power outages,power surges, brown outs and a lot of it depends on where you on the island or which island. 
Basically, it will keep computers and router on for another 43 minutes,which during that time,the power could come back on or allow you to safely shut down your sensitive electronics.
I have two,one is for router and two computers. The other in another part of the house is to protect the two wide screen TV's,one in the bedroom and the other in the living room. 
These APC UPS's also have surge protects for your TV antenna or cable doing into your TV's. Lightning has a funny way of traveling to get to ground,some protection is better than none. I believe it's well worth the protection they provide but then again,we have folks here in America that has never heard of these devices and have never had to use one.
The reasons for having one to me is strictly based on my location and the services or lack of services your local power company can provide.
Now if you are a believer of sunspots and solar flares, then you know that there is a very understandable benefit to own one or two UPS's in your home. It's the last form of defense against all the bad things that could happen if you didn't own one of these. Please keep in mind,that this will not protect your expensive appliances like your Microwaves,the refrigerator,washers and dryers. These are higher amperage appliances that will need more than a UPS to provide protection.
I hope this answers your question and you can find these on ebay fairly cheaper to expense. All I can say is shop wisely and I hope you find the answers that you were looking for.
Semper Fi


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## LincTex

I have enough parts gathered to build two small systems, one on a "budget" and another more "Cadillac". Stay tuned!


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## hiwall

LincTex said:


> I have enough parts gathered to build two small systems, one on a "budget" and another more "Cadillac". Stay tuned!


Oh great. Now we have teaser ads on the forums.


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## LincTex

hiwall said:


> Oh great. Now we have teaser ads on the forums.


Hahaha! Yeah, I recently picked up a used Odyssey PC925 battery that will be the basis of the "Cadillac version". Those batteries are pretty amazing.

http://www.odysseybatteries.com/battery/pc925.htm


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## MT-prep

Great info LincTex, this will be a big help when building my BOV system. Just wish I would have found this before I bought my Goalzero..


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## millertimedoneright

Here's an oddball question from someone who knows nothing about electricity or wiring...would it be feasible to use one solar panel to charge a large battery bank over a long period of time only to use it during outages a few times a year?


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## cowboyhermit

millertimedoneright said:


> Here's an oddball question from someone who knows nothing about electricity or wiring...would it be feasible to use one solar panel to charge a large battery bank over a long period of time only to use it during outages a few times a year?


Yep, as long as the panel puts out more than the self-discharge rate of the batteries. You probably still want a charge controller, though if done correctly you can get away without one in some instances.


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## LincTex

millertimedoneright said:


> Here's an oddball question from someone who knows nothing about electricity or wiring...would it be feasible to use one solar panel to charge a large battery bank over a long period of time only to use it during outages a few times a year?


It would be a "maintainer" only. It would most likely be far too small to ever bring the batteries back up to full charge again once they are drained to 80%. For that, you would need a charger (either grid or solar powered) with enough amperage output to get the batteries back to 100% again.


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## millertimedoneright

Aight appreciate the info I'm looking for a cheap route to have back up power during outages until I can afford a full system


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## LincTex

millertimedoneright said:


> I'm looking for a cheap route to have back up power during outages until I can afford a full system


Cheap = used craigslist generator and 30 gallons of gas. 
It is very short-term use, though.

Batteries are expensive.


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## smaj100

Looking to start my basic off grid solar system. And I'm wondering if these are good batteries? They are selling for $80 ea and are close by from craigs list. The seller claims they are from a cell comm site.

TEL12-105FS, 12V @ 100AH 

They are some biggens.


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## millertimedoneright

I guess I should have clarified I already have a genny for blackouts now I'm looking for something to use off grid since I plan to slowly build up a solar system to where I can one day go completely off grid


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## Viking

smaj100 said:


> Looking to start my basic off grid solar system. And I'm wondering if these are good batteries? They are selling for $80 ea and are close by from craigs list. The seller claims they are from a cell comm site.
> 
> TEL12-105FS, 12V @ 100AH
> 
> They are some biggens.


 Are they AGM's or removable electrolyte caps? If they are gel cell types I'd be reluctant to use them, I've seen failures with emergency lighting systems that had that type. They are the two worth working with. Price is good, just remember, adding batteries later can cause imbalances where the weakest battery will drag down the newest ones. In a way that's why I like 6 volt golf cart batteries because I can add new batteries as long as in equal number to the series hook ups I.E., if I originally have four 6 volt batteries series/parallel for 12 volts I can add 4 new batteries by connecting new/old, new/old, new/old, new/old in series and then tie them, say all new for positive connection and all old for negative connection in the parallel connection. Of course ideally one would do best to get all the batteries with the same lot dates as they will likely be more evenly matched. The ideal situation would be to have isolation diodes for parallel connections but this can be a rather spendy way to go. With the system I have been running on our motor home I have found battery imbalances, wither all new or new/old, new/old as I have run as well, I have not had any problems. Generally the better the quality of battery the less problems you're apt to run across. As LincTex mentioned, batteries are expensive. If you are willing to take the time to do a solar/ battery system please do due diligence research, learn what others are doing that works. When it gets down to the nitty gritty it's the old tech types of batteries that stand the test of time AGM batteries are the newer kid on the block but they are still Flooded Acid Batteries, they just have a sealed chamber above each cell that's filled with a fiberglass mat that absorb charge vapors and condenses them back to liquid which drops back into the electrolyte.


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## LincTex

millertimedoneright said:


> I guess I should have clarified I already have a genny for blackouts now I'm looking for something to use off grid since I plan to slowly build up a solar system to where I can one day go completely off grid


Try to standardize. Example: use only golf cart batteries and 60/80/100 watt panels, etc. and you can always add more of each. As you get larger, you will need to increase wire sizes and (if too small to begin with) the charge controller.

Really though, for a couple hundred bucks you'll have a set-up that will get you near to the standard of living you are at now. Just start small, add more later if that is all your budget allows.


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## LincTex

10A solar charge controllers are now less than $10, which *might* be able to handle 120 watts (10a x 12v = 120w) but I doubt it - - most likely 80 watts or so? I guess it depends on who made it. Some are built pretty cheesy inside.

100 watt solar panels are now down to $129 with free shipping http://www.ebay.com/itm/100-Watt-Solar-Panel-Poly-12v-Good-for-Off-Grid-Boats-RV-/221315292649

Golf Cart Batteries at Sam's club are $85 each (2 needed to make 12v)

That's about $300... I need to change the title


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## AVRnj

Would it be possible to get 230V out of a system like this?


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## Viking

AVRnj said:


> Would it be possible to get 230V out of a system like this?


The Magnum Energy inverter we bought has 120/240 VAC split phase, there are inverters that are available that can be hooked up in series that can be set up for split phase for 240 VAC, split phase means that 120 volts put out by inverter #1 must have a phase cycle 180 degree from inverter #2 120 volts. This would give you 120 VAC on each side of neutral (the connection point of the two inverters) with 240 VAC from the hot terminals of both #1 and #2 inverters. donrowe.com has information on two pure sine wave inverters that can do this that I know of, they are Xantrex Freedom SW series, the 2000 and 3000 watt units that can be stacked for doubling the wattage or hooked in series for 120/240 all they have to have is a stacking cable that connects the phase control of each unit to make the phase to match if parallel stacked or if series connected they will have a split phase.


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## LincTex

AVRnj said:


> Would it be possible to get 230V out of a system like this?


That would dependent entirely upon the capabilities of the inverter you chose to purchase... none of the other components have any effect.


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## AVRnj

LincTex said:


> That would dependent entirely upon the capabilities of the inverter you chose to purchase... none of the other components have any effect.


Viking and LincTex,

Thanks much for the reply!

Do either of you know any power inverters that I can buy that can handle this?

My main issue is that I have well water, and my well uses 230V and I believe 30amps. So when we lose power, no water, which is tough.

I do have a transfer switch that I can hook up to a gas powered generated 230V and 30amps, but I would much rather be able to use solar if possible.

This is a great thread by the way and kudos for all the great info!


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## LincTex

AVRnj said:


> Do either of you know any power inverters that I can buy that can handle this?
> 
> My main issue is that I have well water, and my well uses 230V and I believe 30amps.


OMG!!!! That's 7000 watts!

You would need an inverter that is Huge.... I mean _*HUGE.*_

I do not know of any that large, but then I haven't researched it. I'll bet the companies that supply UPS's to large data centers might be the ones to talk to. Because of "inrush current" to get the well motor to start turning, I'll bet it needs a momentary "peak watt" rating of around 30,000 watts.

I am just going to guess a starting point to make this happen is close to $20,000. It would be cheaper to buy a good used 10KW-15KW generator and 100 gallons of gas or diesel.


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## Viking

AVRnj said:


> Viking and LincTex,
> 
> Thanks much for the reply!
> 
> Do either of you know any power inverters that I can buy that can handle this?
> 
> My main issue is that I have well water, and my well uses 230V and I believe 30amps. So when we lose power, no water, which is tough.
> 
> I do have a transfer switch that I can hook up to a gas powered generated 230V and 30amps, but I would much rather be able to use solar if possible.
> 
> This is a great thread by the way and kudos for all the great info!


As your power requirements increase it's a steep curve for the cost of solar. What I would add to LincTex's suggestion on getting a generator would be to get a large water storage tank or tanks depending on your overall needs and pump the well into the tank(s) having a float switch to control the well pump and then use a secondary pump to supply the water pressure tank for your home. That secondary pump will use a lot less energy and can run on a much smaller solar system or generator. An emergency alternative to the secondary pump could be a 12 volt demand pump like ones used in large travel trailers and motor homes. If you are determined to have a 120/240 volt solar backup system then the type of inverter we bought will work, the Magnum Energy MS4024 PAE is rated 4,000 watts but can be parallel stacked up to four units for up to 17.6KW using an ME-RTR router control to tie them together for common phase. That's one of the reasons we bought this type of inverter, in case we wanted to expand the power needs two of them stacked would supply 8,000 watts. That inverter is just over $2,100 and each additional inverter is going to require equal numbers of batteries, solar panels and solar controllers. Even if one can financially afford to get a system to support all your home power needs in a power outage it's a good idea to minimize those needs down to the bare necessities, that's what we have done. I designed our solar backup system to supply two refrigerators, a freezer and a small amount of lighting, other appliances can be ran but by dropping out other high current demand items. As it is we've spent roughly $7,000 so far and I still have to build the solar panel mounting system and various wiring systems which could add up to another $1,000. We're on a low fixed retirement income so we have to do things by the number but what I'm doing I want to be right and being right is not cheap in the long run. We set up a gravity water system so we're not dependent on any water pump but if we were I would do a pump through system as I mentioned, that's what our neighbor on the East side of us has and I've talked him into putting a large water tank uphill to be spring feed that will give them water in a power outage. He presently does not have an emergency generator and I've told him he should, I think in time he will. As one can plainly see our system is not at all in the D-I-Y setup in this thread but if one was to do a tank pump through water system and use a small RV water pump it's likely this small solar system could power it.


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## AVRnj

LincTex said:


> OMG!!!! That's 7000 watts!
> 
> You would need an inverter that is Huge.... I mean _*HUGE.*_
> 
> I do not know of any that large, but then I haven't researched it. I'll bet the companies that supply UPS's to large data centers might be the ones to talk to. Because of "inrush current" to get the well motor to start turning, I'll bet it needs a momentary "peak watt" rating of around 30,000 watts.
> 
> I am just going to guess a starting point to make this happen is close to $20,000. It would be cheaper to buy a good used 10KW-15KW generator and 100 gallons of gas or diesel.


I actually wrote that incorrectly. My well has a dedicated 20 amp 230V circuit on my panel, but I am not sure it actually needs that much.

That would be around 5000 Watts.

I found this thing for $150 and it has a 220V outlet, would something like this possibly work?

http://www.voltage-converter-transf...php?category_id=10016460&products_id=10061333


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## Wellrounded

AVRnj said:


> I actually wrote that incorrectly. My well has a dedicated 20 amp 230V circuit on my panel, but I am not sure it actually needs that much.
> 
> That would be around 5000 Watts.
> 
> I found this thing for $150 and it has a 220V outlet, would something like this possibly work?
> 
> http://www.voltage-converter-transf...php?category_id=10016460&products_id=10061333


How deep is your well and how much water do you want to pump? Changing your pump to suit your power generation might be the easiest thing to do.

Our well is 300ft deep but water is at 75 feet and we pump a further 100ft head to our storage tanks. The 240 V pump is 750watt, we use a lot of water (irrigate about 1/2 acre heavily, plus water 10,000 pots everyday, a small orchard, small vineyard and stock water) and it keeps up just fine. We have it on a 15 min on 30 min off duty cycle to let the well recharge. We have just (yesterday) dropped the pump further down the well as we seem to be loosing our top aquifer (been in drought here on and off for 15 years) hopefully we'll be able to change our duty cycle to 30mins on 30mins off as of today. We can run this pump from an inverter but it would take a heck of a lot of panels and battery storage. This pump cost under $200.00 AU dollars.
We also have a small 24v solar pump that pumps almost as much water as the 240 v pump as it runs every minute the sun shines plus a bit. We have 360 watts of panels and 2 x N70, light truck batteries on this setup. We source our batteries second hand from the local battery seller. We can get an almost endless supply and we just keep collecting more. This pump cost $150.00 AU dollars.


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## AVRnj

Wellrounded,

My well is 200 ft deep, and I am really not sure where the water is.

I am really only looking to be able to use small amounts of water in the event of a power outage, really just enough to flush the toilets and get some drinking water, nothing more than that.


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## Wellrounded

AVRnj said:


> Wellrounded,
> 
> My well is 200 ft deep, and I am really not sure where the water is.
> 
> I am really only looking to be able to use small amounts of water in the event of a power outage, really just enough to flush the toilets and get some drinking water, nothing more than that.


We can pump to more than 175 ft with our little solar pump, if you're just after emergency water I'd think about setting up a little solar pump. We get ours from ebay, the parts are interchangeable with a much more expensive shur-flo brand so possibly made in the same factory. You could try sounding the well, a piece of tube with a fox whistle glued into one end then attach string and lower when it hits the water surface it will push air through whistle and you'll hear it from the well head. 
Here's ours....


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## Viking

AVRnj said:


> I actually wrote that incorrectly. My well has a dedicated 20 amp 230V circuit on my panel, but I am not sure it actually needs that much.
> 
> That would be around 5000 Watts.
> 
> I found this thing for $150 and it has a 220V outlet, would something like this possibly work?
> 
> http://www.voltage-converter-transf...php?category_id=10016460&products_id=10061333


You will need at least 5,000 watts of inverter power to be able to use that step down/step up transformers full potential. Transformers, some electronics and AC motors like to run best on pure sine wave inverters. That's why I went with pure sine wave inverters, they are as good as grid power and possibly cleaner because there are no line spikes that can happen with demand changes of other people connected on the high voltage lines that you're on.


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## hiwall

This thread should be a sticky. The amount of info is huge. And it is info that many preppers want.


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## LincTex

AVRnj,

I don't think you understand what an inverter is and what it does.

That device in the link you posted states: 


> Converts 110/120 V to 220/240 V OR converts SINGLE PHASE 220/240 V to 110/120 V (switch is on back of unit)


....which clearly defines it as not being an inverter.

Second, you need to know what exactly is inside your well. Until that happens, no one here will be able to help you. If you will be able to fit a small pump past your pitless adapter inside your casing there are many options available, but if you can't do that then your options are limited.
.
.

Thirdly, if this thread is about to become a sticky, then all discussion about wells and pump options needs to cease and desist. You can start a new thread with well specific questions, but I HIGHLY recommend you do a search as there are many valuable threads in existence here that have covered this topic very well.


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## Boomy

I'm jumping in on this waaay late, but to confirm that this systym will work for most. I have family in the backwoods mountains in Mexico. Their house was offgrid for the first three years, and they ran it off of a similar though smaller system. When you have to, you learn to do with less. They were using a little 7w and a car battery. They used 1156 light bulbs from the junkyard at night and an inverter to power the tv for the kids homeschooling by day. To my knowledge the largest thing that they ran was a blender every once in a while. When they finally got wired into the grid they packed up the system and put it into staorage. No issues after three years....

The system that I'm building is a 12v to take advantage of newer LEd tech. This is a car panel upgrade for a riceburner.

http://www.ebay.com/itm/15088695009...X:IT&_trksid=p3984.m1438.l2649#ht_3489wt_1117

It mounts flush and can be installed in conjunction with a 120v relay connected to any household outlet. Power goes out and the now new E-lights come on. If the power stays off, I now have a whole house low voltage lighting. Also newer flat screens pull a LOT less power than the oldschool sets did. I have a litte 20" for the kids to stay sane. My DVR pulls more power than the TV!
:soapboxzipper:


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## LincTex

Boomy said:


> Power goes out and the now new E-lights come on. If the power stays off, I now have a whole house low voltage lighting.


I just added new 12 volt circuits to the house, and can turn them on and off as needed. Some of my 12v LED lights come on at dusk without me switching them on. The interior of my house is never truly "dark".


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## Viking

LincTex said:


> I just added new 12 volt circuits to the house, and can turn them on and off as needed. Some of my 12v LED lights come on at dusk without me switching them on. The interior of my house is never truly "dark".


That's one of the things I should have done while building our home, the other thing is that I should have ran a hot water line behind my wood stove so that it could connect to a coil in or around the stove.


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## smaj100

I saw these at my local farm store. Are any of them good candidates for a solar system? Is bigger better, they are flooded so they can be maintained. .


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## Viking

smaj100 said:


> I saw these at my local farm store. Are any of them good candidates for a solar system? Is bigger better, they are flooded so they can be maintained. .


 The 4EH battery at the top would be the best as it probably has much thicker plates however it would be good to have the amp hour rating on it as it would give a better picture of how long you could run things with it. Usually batteries rated in cranking amp time are mainly used for frequent starting and are not considered true deep cycle batteries. Depending on the quality of the cell plates they may not give the life of say two six volt golf cart batteries. I suspect that that 4EH battery is made for tractors or big trucks that run on diesel and need greater cranking amp reserves, in which case they would probably be better than some RV/Marine types. Find out how much that one weighs, that's usually a good indication as to how much lead is in the cell plates. If you get a hernia lifting it, it's more than likely a pretty good quality battery.


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## smaj100

Viking, 

I did some research and the AH can be calculated as 1/2 of the RC generally speaking. Which gives that 47eh battery a 150AH. On Sale these are running $89ea so I figured 4 will be at least a decent starting point for a small wind and solar system. 

Any recommendations on wire size from a wind turbine on a 20ft pole plus 10ft to the controller? It's a 12v, 500w windmax unit?


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## cowboyhermit

smaj100 said:


> Any recommendations on wire size from a wind turbine on a 20ft pole plus 10ft to the controller? It's a 12v, 500w windmax unit?


There are some good dc wire sizing calculators online, they often will recommend a surprisingly heavy wire but if you are willing to accept a bit greater line loss at max capacity you can get away with a more conservative cable.

This calculator recommends 2AWG for that application (4%loss) or 0AWG (3%loss).
http://www.solar-wind.co.uk/cable-sizing-DC-cables.html


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## Tirediron

Bigger case size should be better at a given rating than smaller case size. I would choose the group 4 batteries ahead of the "deep cycle" rv type especially considering the price. group 4 batteries are usually found in heavy trucks and construction equipment and the construction is much more robust than the RV type. If you maintain them carefully they should give excellent service for the price.


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## Mase92

Sorry to really add nothing here other than tagging the thread for a winter project.

This stuff is priceless.


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## LincTex

Tirediron said:


> I would choose the group 4 batteries ahead of the "deep cycle" RV type especially considering the price.


Golf cart batteries at Sam's are $89 and have a higher Amp/Hour rating than group 4 starting batteries. I would get these instead.

Minutes at 75 AMPS: 122
20 AMP Hour Capacity: 232

http://www.samsclub.com/sams/energi...0037.ip?sprodId=prod6000037&_requestid=244783


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## LincTex

I had someone PM me asking about changing the size of the system to suit their needs.

I forwarded some links to help with the math, I figured I would post them here as well.

I searched: " solar inverter battery calculator "

Here's what I came up:

http://www.thediyworld.com/The_Solar_Panel_Requirements_Calculator.php

http://www.batterystuff.com/kb/tools/solar-calculator.html

http://www.electricaltechnology.org/2013/05/a-complete-note-on-solar-panel.html

http://www.cleversolar.co.uk/shop/help-advice-faq/battery-bank-size-calulations.html


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## Tirediron

LincTex said:


> Golf cart batteries at Sam's are $89 and have a higher Amp/Hour rating than group 4 starting batteries. I would get these instead.
> 
> Minutes at 75 AMPS: 122
> 20 AMP Hour Capacity: 232
> 
> http://www.samsclub.com/sams/energi...0037.ip?sprodId=prod6000037&_requestid=244783


Wow it really depends where you are located for pricing, golf cart batteries are at least twice that here,


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