*Battery Bank from Free Batteries*
By: SlimJim
15 July 2005

"Free batteries. Perfect gift for mother in law," the sign said. My friend had given me the tip that the state office building was trashing about 60 deep cycle 12 volt batteries from their battery bank.

When a company employs a battery bank for backup use, they don't really care about the cost. To maintain near-absolute reliability, they will replace the whole bank of batteries every few years. That was the story here. These work just fine, but they were being given away as junk.

The batteries are of the AGM (Absorbed Glass Mat) type, which means that the acid is contained in a mat of fiberglass-type stuff, they don't slosh like a normal lead-acid battery. This also means that they don't vent gases, so they're safer; and they don't need to be refilled with distilled water. In fact, there are no openings in the battery case at all. They are spill proof, freeze resistant, and pretty durable for a 12v battery of this size. If they weren't free, they would cost quite a bit more than a flooded cell battery.

I built a shelf in the garage for my five-battery bank. This shelf has to be sturdy, so it's screwed into the studs as well as supported by a 2x4 leg under the corner. It is near the south wall of the garage, so I can eventually hook up a solar panel. It is near my wife's car, so the bank can be recharged with jumper cables. It is near the breaker box, so that eventually I can wire it up as a whole-house UPS. And finally, it is near a plug in, so that I can keep the batteries topped off with a trickle charger.

The cables are made from a pair of heavy gage jumper cables, cut into sections. I then made cable ends from 2" lengths of 3/8" copper tubing. Smash the end flat, drill your bolt hole, and solder the ends onto your cables. I wrapped the ends with electrical tape to cover the burned rubber insulation.

My inverter is a Coleman Powermate 2000, which I have used for about a year in my off-grid Yurt. It can comfortably power a microwave, tv, power saw, etc. The only time it has given a squeal was when trying to run a horse pump at the end of a 100' extension cord. Harbor Freight used to sell this inverter for less than $190, but I didn't see them the last time I checked.. They are a good product, and has worked fine for my uses.

Hopefully this article has encouraged you to go out and look for alternative sources of deep cycle batteries. Ask around at office buildings, phone companies, hospitals, and anywhere you can think of who might need uninterrupted power. Alternate power isn't hard. It's as simple as jump starting your car

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