Motherload of lithium

[erdurbin]

I just grabbed 45 (more to come) used Milwaukee Lithium Ion batteries. They are all 28v 3.oah LiMn technology. I took 12 packs apart so far and they have 7 cells each. For the most part, either the whole pack is bad or there are only one or 2 cells bad. Surely out of this vast supply of batteries, I can get enough good ones for a 36v pack. Right now, I want to do a 15ah pack which would involve 50 cells.
10 cells for 36v 3.0ah in series, then 5 of those together for 15ah.

So far I have around 30 good cells measuring around 3.6-4 volts. 30 out of 84 is not bad considering they were FREE! The others are either totally dead or are measuring 1.5v-3.4v. I hear these can still be used, but a lot of them look like they have a brown substance on them.

I am looking for a BMS and charger over at batteryspace. Anybody else have any suggestions?

[OneEye]

Awesome!  Glad it worked out for you.  It's nice to see Doctorbass on the Endless Sphere forums isn't the only one who can get some recycled joy for nuthin'.

[mustangman]

 On the endless sphere site, a person was able to revive some of the dead batteries by using 2 alkaline "d" batteries to revive the dead cell so it will accept a charge from a AC 110 volt battery charger for lithium batteries. If you get more and want to sell "rebuilt battery packs" I am sure their is a market right here and I would like to be one of the first customers of your new project. Good Luck!!!

[myelectricbike]

Correct me if I'm wrong but amp hours, unlike amps, can not be increased by wiring batteries in parallel. What you have to do is switch from a discharged pack to a fully charged pack every, err ...10 minutes? Don't seem right somehow though does it?

[erdurbin]

No, if each pack is 3.0ah and you wire them in parallel, say 5 packs = 15ah because it will not draw as many amps from each pack because it is spread out more. Plus, if you used a 3ah pack alone, you would not get very much life out of it because you would be discharging at such a high C rate.

For example, 30 amps drawn from our motor would be 10C on one pack. In parallel, the same draw is only 2C on each pack. Much easier on your batteries and much more distance.

If you think about SLA, the bigger ah batteries are physically larger in size because it contains more of the same cells, just in parallel.

[myelectricbike]

That makes sense to me but I think it was on the PowerStream page in the new LiFePo4 section or in a post on forums.batteryspace.com that someone responded that amp hours could not be gained by connecting batteries in parallel. The LiFePo4 packs PowerStream or batteryspace sells ar also limited to 3 Ah and it was the salesman or their tech rep that responded to the question.

I have four batteries, two with bad cells hooked up to my UPS and where it use to fail immediately it now goes long enough for power management to kick in and shut everything down in a methodical way with enough power left over to keep the UPS power outage beeps going.

[mustangman]

  Still no luck in Fresno service center. I had a long talk with one of the employees and he stated that in this area the lithiums have not caught on with the local contractors. They are still using Nickel based batteries , however, as the price continues to become more attractive they will see more lithium systems enter service(and need repair and batteries). So for now I will just have to wait for a few months.

[erdurbin]

I called around 8 service centers across the state of Kentucky. Many only had 2 or 3. One place had 6 and wanted to charge me $5 a piece for them. But, when I called the center that had 45, you could imagine the smile on my face.