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Old 09-26-2005, 06:53 AM   #1
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Unhappy Quick battery question number 2. What's that noise.....

Today I finished soldering up my first Nimh Battery packs (9 x 4 cell GP 3700 unmatched vis and 3 x matched packs).

I'm charging each one a 5 amps and timing the discharge @ 20 amps (only discharger I have at the moment).

Anyway two of the batteries (so far as I've got 7 to go) have behaved differently.

The first one was different because it charged to .05 (cut off at 6.04) volts less than the others and has been the only one to get hot (not slightly warm) to the touch during charge.

During discharge this battery lasted 2 min less than the others (they lasted approx 20 min).

The second one is very odd.

It charged to 6.08/6.09 like the rest (and only slightly warm) but again the discharge time (down to 3.6 volts) was 2 min less than the rest. But the really odd part was that as it got down to 3.8 it started to hiss as if it was leaking.

Not the normal venting sound I've heard on other batteries (and no funny smell or anything) , this sounds like a slow leak and if the battery builds up it's voltage after a rest it's fine until once again it gets down to 3.8 when put on a discharge.

Any ideas what this might be/can it be fixed or should I just junk them?

Thanks in advance.

Last edited by Mabuchi540; 09-26-2005 at 04:34 PM.
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Old 09-26-2005, 11:43 AM   #2
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when you say hot, what was the temp around?? is there any way your charger false peaked, beacause 2 min is a big diffrend. although they are unmatched, i dont think the diffrence would be 120sec. i believe the hissing means the acid inside is slowly leaking i think it wont last much longer so i think u should junk it. your paks are unmatched so there will be diffrences between them. record all #s and set your practice paks from main paks, and u should be good
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Old 09-26-2005, 03:43 PM   #3
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Post Thanks.....

Quote:
Originally Posted by geeunit1014
when you say hot, what was the temp around?? is there any way your charger false peaked, beacause 2 min is a big diffrend. although they are unmatched, i dont think the diffrence would be 120sec. i believe the hissing means the acid inside is slowly leaking i think it wont last much longer so i think u should junk it. your paks are unmatched so there will be diffrences between them. record all #s and set your practice paks from main paks, and u should be good

I should have mentioned that as for charge time they were all approx taking the same time (say within 1 min of each other).

As for how hot, I don't have a temperature as such but I'd easily say I've not felt a battery that hot until after a race.

One for the junk pile and maybe another huh? lol
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Old 09-27-2005, 01:21 PM   #4
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if you go on team express's web site williams sez that a battery can get up to 135degrees . I'm pretty sure from what i know the hissing is the battery on its way south, it may still run, but probably not 4 too long. if the battery was really getting hot, it has a higher internal resistance, whch means less speed during your runs, so that 1's a practice pak
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