For about 6 years, I've been living off what was a nice set of surplus phone system backup batteries. They are huge and heavy...probably about 3000 pounds worth, 1400 amp hour 2v cells all in series for my 24v system. But, they are sealed gels, and I've rather abused them, they have gotten quite weak. I've been worried.
Then, a couple months ago, I got a call at the office.. a local fellow had built an electric using these 170ah 8 volt golf cart batteries. He had used them for about two years, estimated about 500 light duty cycles, and decided he wanted to switch to sealed batteries for safety concerns. I was, of course, skeptical.. but, had to look. I only checked a couple of them on site, and both measured right about 8.3v, and they'd been off charge for over a month. So, I loaded them (yes.. all 18 at once) in my Volvo (poor car) and took them home.
Upon getting them home, I put them in an outbuilding until I could build a new battery bank adjacent to my existing battery/power room. That was two months ago. Every weekend I had the time to build my new battery box, the weather was lousy or I had to play golf or get firewood or what have you... priorities, you know.
Finally, last weekend (in another snow storm), it occurred to me that I had a lot of square feet of space on top of the huge steel racks that house the old batteries, so I simply made a platform on top of them with 2x6 sections I'd gotten off Craigslist a while ago.. they were actually already cut to the perfect size, and in no time, I had all those batteries moved and in place.
New batteries in place atop my old batteries.
Yesterday, I commenced to hooking them all up. Plan was to hook both batterie banks to a knife switch so I could switch them, manually.. if one is full and it's windy or sunny, I flip a switch and run off the other... First step was to measure all the new batteries, as I'd yet to do that. Now 3 months off charge, and stored in the cold outside... the lowest came in at 8.23v, one was 8.26v, the rest were between 8.29 and 8.32. good enough says I.
We have a large spool of 4 gauge wire, and a neighbor had a bunch of solder empregnated connectors for 4 gauge, as well as some for larger wire. You use what you got, that's what I did. I started by making up 12 cables to tie together groups of 3 batteries each in series into their final 24v configuration. Then, 10 more cables for my parallel connections.
Here, soldering the cables. Nice connectors.. just heat to melt the solder within, stick the wire in and try to avoid molten solder splash.
All batteries hooked up.. came in at 24.78v as a complete bank. Again, that's having been off charge and in the cold for over 3 months.
Hardly a good schematic, but it gets the point across better than I'd be able to describe it.
I know this ain't pretty... I will get it orgnanized. It is quite functional though, and well fused.
When I first hooked it all up, and threw the switch, the trimetric was showing total voltage of 23.9 (with 3 amp outgoing load). After about an hour, still before the sun, and zero wind, the fridge and computer, along with lights, had increased the load to over 12 amps, and the trimetric was showing voltage increased to 24.2. I expect these probably have more than twice the capacity of my old, tired sealed batteries.
I have a good feeling about these batteries.. Of course, golf cart batteries are not ideal, but for the price... I'll take 'em. Out of pocket expense was pretty much just the nut and bolt hardware to bolt the cables on. About $20, and about $5 for the craigslist boards, a little extra gasoline for hauling 1800 pounds of batteries, one old pair of jeans, one shirt, one pair socks (battery acid). Everything else was free, or laying about at somebody's house nearby.
A HUGE thanks to Ross at volt914.com for calling us rather than sending the batteries to the recycle center. They have some life left in them for sure. Check out his EV blogs.. he's got the Porsche 914 project, which is where these batteries came from. He's also working on a Jeep Cherokee EV project. Neat stuff.
Dixie was absolutely no help at all... I can't blame her.. wiring is harder for her these days, as she don't see as good as she once did. But, she didn't even help clean up afterwards. All she wants to do anymore is play with that damn flippy flopper. Ah well.
