[NSRCA-discussion] Battery puffing question?

[Verne Koester]

Stuart,
I've had cells puff with the pack just sitting on the bench. In one case, 
the pack was brand new and I hadn't even soldered a connector to it yet. I 
checked the voltage and it was about 19.5v on a 5-cell,. Another time was my 
fault when I left a pack fully charged for about a month because of lousy 
weather at the end of last season. The manufacturer replaced both of those 
packs at no charge.

In any event, with what Anthony described, I don't think I'd tempt fate by 
putting a charger on it.

Verne Koester


----- Original Message ----- 
From: "Stuart Chale" <schale at optonline.net>
To: <aabdu at sbcglobal.net>; "General pattern discussion" 
<nsrca-discussion at lists.nsrca.org>
Sent: Saturday, November 01, 2008 6:40 PM
Subject: Re: [NSRCA-discussion] Battery puffing question?


> As lipos get older and weaker (we then push them harder) they will tend to 
> swell a bit when hot but should return to normal when cool.  If they stay 
> puffed up then at least 1 cell has gone bad.  I have been told that cells 
> only puff when they are flown to too low a voltage.  If always kept at 
> 3.6/3.7 per cell at the end of the flight, 80% or so of usable power, then 
> they should not puff.  They still may weaken and fail but shouldn't puff 
> up.  Are you sure that you charged the pack before flying?  That would be 
> the quickest way to go well below the safe voltage limit.  Flying 2 
> flights without recharging :)
>
> Stuart Chale
>
>
> Anthony Abdullah wrote:
>> 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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>
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