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Old 05-30-2007, 08:57 PM   #1
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Default Battery Charging Question

I have been charging my batteries (IB4200) on a Duratrax ICE with a temperature probe. I had been using the temperature probe more for curisoity than anything, and I put the shut off at 120 degrees. Today at the track, about half of my packs (3 of 8) ended charge prematurely with an over temperature warning.

how hot should I allow the batteries to get? All the packs were over 3900 milli-amp hours. I seem to remember I read somewhere that the packs should come off of charge at 130 degrees??? Is it normal for my packs to start to increase their final temperature as they get older when they are ready to come off the charger?

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Old 05-31-2007, 06:55 AM   #2
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SMC recomends or states that a pack can come off a "peak detection" at around 140F. So set your charger to peak 30mv for a 6cell IB and use the temp probe as a secondary cut off devise. Im not crazy about charing by temp as your stuff could be hot form outdoor use or cool form indoor use. Im pretty sure though that the temp probe on the ice is for secondary cut off not to actually charge by am i correct?(ino other words if you set it to 200F it would not force charge till it go to that temp) But i suppose if you set the cuttoff at 90F that you would never get the packs completely charged.
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Old 05-31-2007, 07:36 AM   #3
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That's hot! I guess thats why the guys that have been doing this a while are charging their batteries in the car

yes, you are correct, the temperature probe is for shutting it off if something goes wrong, it won't charge until that temp. As far as inside/outside temperatures, that is probably what happened, it was a warm day in the midwest yesterday, and the ambiant temp inside of the building was higher than normal, so the packs reached a higher temperature. I'll check the detection threshold, and reset the temperature of the probe.

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Old 05-31-2007, 05:01 PM   #4
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Quote:
Originally Posted by Section 8
... I put the shut off at 120 degrees... how hot ... packs were over 3900 milli-amp hours... should come off of charge at 130 degrees? ....
I have seen it recommended (e.g. Promatchracing.com) to have packs peak at 120 to 130F. However I have also seen that some 4200's come off hotter. My latest good packs are good EP4200's and they peak in the mid 120's on a lukewarm day (70's) with 3mV per cell (0.018V total) cutoff in NiMH2 mode on the Ice. I would probably set the temp cutoff to 132F for club races ... maybe go up as much as 140F for a big race.
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