LifePo safe?

[limpet]

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?

[terry]

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

[maddox10]

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.

[limpet]

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

[Rapidrory]

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.

[limpet]

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.

[maddox10]

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.

[Rapidrory]

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).

[limpet]

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.

[maddox10]

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

[typhoon_driver]

I'd stop messing around with the crap hobbyking brands and get yourself some optipower or similar. Big discount on optipower with FRA membership as well.

[maddox10]

We have good results with HK stuff tough.

Just keep in mind Chinese amperes ain't the ones we're used to. Call them hobby amperes.

[limpet]

Any recommendations before I part with the cash please?

[maddox10]

After calculating all the tidbits, Optipower isn't that more expensive than the "better" HK packs.

So support a local supplier.

[limpet]

Found out there is an Optipower supplier where I live so will go and see them (Midland Helicopters)

Thanks all