My A123 cells are dying... help?

[JThiessen]

Originally Posted by wulfgang

I can't do 6S2P! This is a buggy, not MT. Remember that I said it is already too heavy with 6S1P? I'm looking to go down to 4S, and there are plenty of people running 4S A123 with inrunners.

The cells came from brand new Hypersonic 2S2P packs. However, I bought the packs from a hobby shop on ebay.

Thanks for the comments, everyone. I'll probably just get the MMM and see where it goes from there.

I was waiting for you to tell us where you bought the packs. I'm now 100% certain that you have the same packs that I purchased from Hopmeup.
I bought 6 4S2P packs, and out of those, I had 5 bad cells. There are many others that have had that same thing occur from this vendor.
I was able to get two of the cells "recovered" by pulling the packs apart and charging the individual cells back up using a low ampreage Nimh setting on my Hyperion. However, I have had to be diligent with the pack they are in because it is overly suceptible to over discharge. I had a thread a while back venting about this vendor and the way they treated me, but when you do the math, the price per cell was pretty low. And I learned a LOT about creating packs. I also ended up with a GREAT soldering iron (Hakko), which if I were you, I'd get something similar. You wont regret the investment. The pencil irons just dont cut it. I have applied more than 5 seconds of high heat to a cell in certain instances and have not had an issue. My choice was to either keep heating it to get it to flow, or throw the cell out - so it was a no loose situation. And yes, that was with the Hakko. Sometimes, some vairiables make even a good iron a moot point.