Picked up a few GC2 6 volt batteries from Sam's club, and looked around for a battery box big enough to hold both of them.....well, no way in hell I was spending $100 on a plastic box so I came up with this.
















I still need to make some type of wheeled platform for it, I have an old creeper under it atm. I might also mount a battery tender to the top as well.

Damn - That is one bad-assed copper buss bar!

Might want to seal up the backside of your digital volt meter - The batteries will be giving off enough fumes to corrode those tiny PC board traces real quick.

Why those batteries instead of a car battery?

Car batteries don't hold up to deep drawdown in charge. A battey power supply must.  

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

Car batteries are only STARTER batteries. You need a battery that can handle a big draw for a long time, such as marine deepcycle or better yet, golf cart batteries or powered wheel chairs, etc. They can handle being drained down and then charged up. The only drawback is the longer recharge time it takes.

Looks nice but you're heading for trouble. Batteries need to have an inch along each side to allow for airflow to keep heat from building up, and some actual airflow, too. Also the cooler will act as insulation to keep heat in, as well as keeping in the hydrogen gas mix they will give off during duty cycles. Don't mean to be a PITA, and the setup looks well-crafted, but you're heading for problems. This comes from years in the battery part of the solar industry.

They're deep-cycle 6V golf cart batteries,

That's a sweet setup! But those coolers aren't exactly cheap either lol



"Freedom isn't Free"
Another great site worth checking out: Survival Forum

Unless he's recharging them rapidly or powering a load that draws hundreds of amps, there's not going to be much heat buildup. And, having them in an insulated compartment could be an advantage in some situations - Keeps 'em warmer in the winter, so they don't lose as much effective capacity when the outside air temperature drops overnight.



The hydrogen is vented through holes in the battery caps, not via diffusion through the walls of the battery case. Any battery compartment can have problems with hydrogen accumulating, insulated or not. The key to preventing it is ventilation, not lack of insulation.

What Ski Said.

Put a few small holes in the lids to let any H2 escape. Prolly not necessary considering the gap between the plastic and the plywood, but should make the worry-warts happy.

There is a 1/4" gap between the lid and the cooler, if you look at the first pic you can see the 5/16" screw heads at each corner. As for heat buildup? I could always throw ice in there.....it IS a cooler after all.

there have been some valid post about heat issues. I like your setup, re-purposing a cooler into a functional portable power supply.

I would suggest drilling a dozen or so 1 inch holes in the cooler to reduce the heat. Unless of course you intent to use the cooler as a cooler again.

How much does it weigh? 130lbs? What size cooler?

Closer to 150 # I would guess, the GC2's are 62#'s each.

Have dimensions or at least quart capacity of the cooler size? I have a shit ton of old ones, that I may re-purpose.

Inside dimensions at the bottom are 21" X 9", don't know the quart capacity, bought this thing about 15 years ago.

Good point on the back of the meter, didn't think about that, what would you suggest?
The copper bus bar was a scrap piece of 5/8" refrigerant copper I had laying around, just beat down the ends with a hammer and drilled a few holes...saved me from making another cable!

I'm surprised no one spotted the flush and fill fitting yet!

Piece of sheet metal, attached to the back of the plywood with wood screws. If you want to get fancy, run a bead of hot melt glue around the edges of the sheet metal before screwing it to the plywood - or stick a piece of soft foam rubber sheet (available in the hobby & crafts  section at Wal-Mart) between the sheet metal and plywood to serve as a gasket.

Well, I usually defer to Ski, but I'd screw a piece of plastic there w/ two sheet metal screws and put some aquarium silicone sealant under it as a gasket.

[From W-M]  

Can;t find it, where is it?

Also a cigarette lighter recept or two might be handy on there.

And, be sure to fuse the little skinny wires to the meter etc, soldering them in line with some shrink over them would be OK.

How would a deep cycle Optima work for a setup like this as compared to the golf cart batteries?

Golf cart batteries will usually last quite a bit longer (i.e., endure more deep discharge/recharge cycles) than the deep-cycle Optimas. They're also quite a bit cheaper. However, Optimas and other sealed batteries aren't as messy as flooded-cell batteries like the golf cart models, and don't require occasional watering or battery post cleaning.

Convenience vs. longer life and lower cost. Take your pick.

It's where the drain was on the bottom right, where the charging pigtail comes out.

If you look on the front right side there is a lighter receptacle with a USB charging adapter, I will probably add another down the road.

Don't see a need for a fuse inline to the meter, that goes directly to the batteries. Why would I need a fuse there?

I went for WalMart's biggest marine/dual-purpose batteries 7 years ago when I needed some serious battery storage.  I was converting a school bus into my skoolie.  I used a set of 3 for my starter set and 4 more for my house batteries.  I spent months reading skoolie & RV websites & forums, reading books on 12V/24V/48V systems for RV, solar & off-grid.  Yes the big forklift RV batteries have a long lifetime.  And yes the banks of 2V batteries used in some off grid have advanatages.  

But after taking into consideration cost, usability, weight (yes even a skoolie with a 27K# GVW needs to think about weight, & besides *somebody* has to lift them into place!) I went with the WalMart batteries.  Because no matter where I go, if I needed a replacement battery I wasn't going to have to go far to find a walmart or suitable substitute.  They have a handle on them making them easier to carry,

My house bank did die en mass when someone broke into the bus and ripped out my LED lighting.  I had not switched to full disconnect and the shorts to ground killed the batteries.  But I did get 4 years out of those batteries with only one needing replacement before then.  My Xantrex inverter/charger did a good job of keeping them conditioned and I had things wired so that the house could be isolated from the starter batteries to keep from draining those when camped.  Or connected allowing the alternator to keep all charged will driving.  I would do this again if I decide to put "The Druid RV" back on the road again.  Or replace it with another.  The same logic leads me to plan my storm shelter with the same kind of batteries.

Grinning Wolf

Most decent sized cities have a sam's club and every sam's club I have been into had a pallet of the golf cart batteries, they actually had 2 different types and a pallet of each but I forget what they both were.



I am going to pull a dead engine off a push mower and use the rolling base as a cart and stick a couple of these golf cart batteries on it.  They are heavy but for around the house stuff or rolling it onto a trailer to haul to a hunting cabin I think it will be nice.





Everyone has to decide what fits their needs and what they want to mess with.



By no means am I about to say one way is better than another way, it all comes down to what the person wants to accomplish.



I know there are more walmarts than sam's club stores but I know everywhere I go there are sam's club stores in the larger cities and if it really came down to it I expect I could have napa or anyplace direct me on where to go to get some more golf cart batteries if they did not have any in stock.



Just because I prefer to keep circuits seperate I will say if I do something where I have a battery bank for power and a battery bank for running the vehicle they will be mostly seperate.



Since larger vehicles often have several batteries for starting I would probably run a few items off that circuit but it would have its own complete design and then the house section would have its own section.

How will you recharge the batteries without an electrical power source?
Wondering for myself, want to build a battery power source for my use but wanting to know how to re-charge it in a power outage.

Generator or solar

I believe it was epicenter.com that had the plans for a pushmower+car alternator contraption that was basically a push-around 12v generator. Looked pretty handy and simple to make. I'll try to dig up the link

In a pinch, a good set of battery jumper cables and any nearby automobile will work. If your batteries are heavily discharged, you may have to run the engine for a few hours to bring them back up to a healthy state of charge - but it'll do the job.