LifePo safe?

I have charged a new battery (Zippy 4S1P 4200mAh 30C) and it seems to have bulged down one side, its more like an air pocket and is not solid. I hadn`t used it and it was balance charged correctly along with the others.
Unfortunately its out of warranty as I got it at the beginning of the year, I got 8 and the other seven are fine.

Would this be considered safe to use?

No you will have to dispose of it at the correct place.

Not abnormal. Did you measure the cells in that pack?

If the cells after a working cycle differ in voltage by .5% then there is something afoot. More than 1% gets iffy.

But in the end, even with huge differences, the LiFePo4's won't burst into flames after real problems. Becoming a great smokegenerator is possible.

Also, if it is a HK Zippy LiFePo4, and you registered the pack by barcode, the warranty is 1 year.

Thanks.
I didn`t know about registering them but I will look into it. It hasn`t exploded yet :)

I bought a load of them around the same time, and after just two events they're all puffed to hell, same happened to Shockwave; there seemed to be a dodgy batch right around Season 1. They'll run your robot fine without exploding if they're LiFE, but don't expect them to last too long.

Thanks Rory - guess what, I asked Will what he was using in Shockwave and bought the same! will doubling them up help do you think? two pairs in parallel to give 8s.

We ran 4 5S packs (33V 8.4Ah) in Bullfrog. They puffed aftere a few charges, but the cell measuring told us that the cells themself were ok, and used them for another 3 years.
Untill one got drilled and went smokebomb.

Yeah, it seems to be high current spikes that kill them; I had a few puff up when Big Bully stalled a motor and blow an ESC, and the rest died when I was using them while load testing my new ESCs. In Nuts for Season 1 I designed for 3 packs in parallel, 2 in series to give 12.6AH at 8S. This was to get the current required to run the electric lifter mech as well as the drive. Once the lifter mech was removed I dropped it to 2 packs in parallel (8.4Ah).

So....
I now have 7 of these batteries left and I either buy another to have the two sets of four again or I treat them as a 1 set (and 3 spares) and buy something a bit better.
My winch motor will apparently take 120A and the drives are Bosch 750, all on 8s. Would these be a better bet does anyone think?
https://hobbyking.com/en_us/turnigy-...lipo-pack.html
or do I need to go higher? I hadn`t got the winch when I bought the first ones.

I wouldn't use the nanotechs. Those puff when you look at them.