[NSRCA-discussion] Battery puffing question?

[Dave]

I don't think you can 100% define when/why a lipo puffs, but you can
generalize some points which increase the odds of a lipo puffing -
- deep discharging is bad
- leaving charged while idle is bad
- exceeding 130F is bad
- running it hard after a period of rest is bad
- older lipos are more likely to puff

All of the above are relative, ie, there is no magic number for % discharge
that will guarantee "X" number of cycles.  Combining one or more of the
above is an additive effect - leave an old lipo sitting charged, and then
heat it up running it hard in hot weather and use 80+ % capacity, and that
is the most likely to result in puffing - and if it doesn't, that would
still seem to be the scenario that will shorten the life the quickest.

Once a lipo has puffed (or been dented, bent, or otherwise mechanically
mangled), it may or may not show any short term degradation in performance
(imbalance, reduced power, running hotter, etc) - but you can bet the odds
of it puffing are increased and the performance is more likely to decrease,
and the longevity of the pack is decreasing.  Once a lipo starts to
noticeably deteriorate in performance, the deterioration is usually pretty
fast.

Regards,

Dave Lockhart



-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org
[mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of Anthony
Abdullah
Sent: Saturday, November 01, 2008 5:01 PM
To: General pattern discussion
Subject: [NSRCA-discussion] Battery puffing question?

I have a Zippy-H 2200mah 3S pack that I use in a small electric plane. I was
flying it today and it the plane lost power pretty quickly. I landed and
noticed that the battery had puffed on me. It was warm to the touch but not
hot. I let it cool but it is still a little puffy almost like a ziplock bag
with a little air in it.

Question: Should I try to cycle the pack or just chuck it and move on? Are
Lipos kaput once they puff or can they still be used? I didn't abuse the
pack and it barely flew long enough to warm up.

Thanks for any info and suggestions.
Anthony

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