Are these old (new never used) LiPo safe?

[GordonFreeman]

These have been sitting in a hobby store for about three years. Many of them had "puffed" out all by themselves and the owner decided that not only was nobody interested in them, but if they ever did sell that they could be unsafe or not work well.

So I took a couple to try/test (maybe over charge massively if I can't find a good use for them ;) )

I took the shrinkwrap off to inspect them and most of the cells have corrosion on the tabs. There is also a small amount of "stuff" that oozed out of the seam by the tabs.

Thoughts?

[nicholcgn]

To me they look like puffer packs for you to overcharge and make a video to scare everyone. Odds are if he had them for a while and some of them puffed he did not maintain them in the store. I would not risk fire for that. Also if they are old the discharge rate is probably not very high.

[doubleback]

if they are puffed they are no good. The pack should be smooth and flat.

[WJ Birmingham]

That stuff that "oozed" out at the seams is the electrolite. Looking at the soldering, it was probably cell seal failure caused by excessive tab heat during the soldering.

[rocknbil]

Gordon if you haven't already, read this thread (http://www.rcgroups.com/forums/showthread.php?t=209187). I am new to lipos and they are awesome if properly handled and charged but deadly (okay, maybe not deadly :D) if overdischarged or improperly charged. And when they burn, thay burn at temps exceeding 1000°.

Lipos don't go with a little pop like other batteries. Houses and cars have burned down. Overcharge them? Guaranteed fireworks. In fact, most fliers using lipos use a "bunker," a ceramic container or an ammo box to charge them in.

So if there's any doubt, which I think there's a great deal of there, dispose of them and that thread shows how to do that safely as well.