Lipos yuk

Opened my box of lipos that I have for my F3A plane all bought from HK at the same time and all stored at the same charge
Now why do you think this happened, perfectly good batteries when stored, I know it's been a while since, BUT $#@%^%#@:evil: [badass]

Obvious problem - they're in a metal box!
I can't see how you have the 'hot' ends plugged up, or if there is any insulation there, so I'd guess that that particular pack has been intermittently shorting out.

I would agree I have never had a LiPo puff like that except as a result of some gross over rate discharge or short.
The fact that all five cells have puffed identically suggests that all the cells suffered the same over rate discharge.
I am never keen on storing LiPO physically touching each other and definitely not with their leads touching.

That battery must have been close to catching fire. If it had it quite possibly could have taken out all of the others!

The ends of the leads were all capped off, have been since new, took the caps off to fly then on again until charging then straight back on so no way have have they ever shorted and there is a lining all around the box :evil: [badass]
And they were never taken below 20% discharge as each flight i timed on the tx

Here are the caps on the wires
And here are the recycles with the %before and after flying

Fine but are there any clues on the one that puffed?
Possibly a fault inside where the leads are soldered on?

BB, most of the F3a guys in UK have moved away from Zippy Compacts for the very reason your photograph shows. I'm now using HRB from China via Germany - search Ebay. Had two seasons from them and only lost one due to flight damage when i pancaked the Acuity onto the tarmac!! The other one survived the crash.

The top F3a guys are using Optipower but i'm not willing to pay £100+ for a single pack.

Ha it's not just me then I paid £150 each for the 4 thunder power 6s 5000 that went into my Sr71 , never again, cannot do electric anymore as we cannot get lipos into the country now
The connections on my zippy are ok, so that's not the reason

Is it possible the battery was accidentally put away fully charged on a warm day? A 20^oC drop in temperature will do that to a battery.
This has been said before, Lipo batteries should be stored with only a storage charge in them.[badass]