[fireyice01]

Hello all. I work in a data center, and we recently replaced our UPS systems. As part of this project, I was given the opportunity to take the old UPS/ATS system home. Unfortunately, the system was a 3-phase 480 volt system and there was no means of connecting it to my 220v home power. I did take advantage of the battery pack+rack and have that sitting in my garage now

The batteries were originally wired in series, 18 batteries in a row, and then each series wired in parallel, there is a total of 72 of these batteries. Since I am not going to be able to take advantage of the large pack voltage, I went ahead and wired them all parallel, so I have a very large 12 volt pack, and am trying to keep it maintained at this point with a puny 6 amp car battery charger. It seems to keep the pack voltage just above 13 volts, but I really need better suggestions of how to keep these things charged/balanced until such a time that I can afford the solar/wind charge controller + inverter equipment to take advantage of these.

Currently the batteries are about 2-3 years old - they were all replaced at the same time, and should be about the same health/age. Attached are 2 images, one of the battery label, and the other of the rack full of batteries.

 

[fireyice01]

Yea, I was stoked when I got them. The racks really make everything fit together very well, and I can actually roll the whole thing around the garage, despite the weight.

Unfortunately, I haven't a clue what their capacity is; everything I know is printed on the label.

I didn't really expect too much out of them; just that if they could run our data center with dozens of 400-1000 watt servers for 25 minutes then it should be able to run the house for a couple hours. To start, I'll probably just run my server rack (another freebie from an upgrade, 3 x 300 watt servers) so that I don't lose my network when the power goes out and expand it's uses to lights and small electronics from there.

I do need to figure out the pack capacity though - based on the info displayed on the sticker, is there a formula to figure out how to convert from "284W/cell 15min" to Amp-hours/kilowatt-hours?

Thanks!

~Jon

 

[fireyice01]

Thanks guys, that's some great info! Really appreciate it!