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Old 08-22-2003, 10:39 AM   #1
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Default Cooling Batteries While Charging

i was wondering if while cooling the batteries while charging helps?
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Old 08-22-2003, 10:43 AM   #2
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You should not try to cool them while charging.
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Old 08-22-2003, 10:43 AM   #3
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and whys that?
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Old 08-22-2003, 10:46 AM   #4
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From some testing I've seen cooling cells whilst charging is a bad idea, it degrades the cells a lot.
http://www.users.zetnet.co.uk/pro-trak/
gives some very useful info on metal hydrides.

Maybe its because the inner of the cell is getting hot from charging whilst the outer of the cell is getting cooled, with the range in temperatures causing damage. Thats just a guess by me, maybe some one with more cell knowledge will say different.
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Old 08-22-2003, 10:48 AM   #5
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goo to the smc website.they explain why.If your talking about 3300's.They should get about 140 degrees @ optimum charge.
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Old 08-22-2003, 11:35 AM   #6
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Default Cooling Batteries While Charging

If you look at the Fastest racers at your local track, they will have their Packs on a Fan while Charging. So what's up with that?
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Old 08-22-2003, 11:50 AM   #7
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thats a good point. I do notice some racers cooling their batteries while charging. Maybe they don't know about hurting the interior of their cells. Also, it is not good to re-charge the battery after running correct? Let them cool for about 10 mins or so correct?
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Old 08-22-2003, 12:03 PM   #8
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I don't cool to charge. I cool when discharging or after a race though. SMC's site does a good job describing why not to do it.
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Old 08-22-2003, 12:11 PM   #9
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Cooling the cells reduces the resistance, thus giving inaccurate peak detection. The cells can be overcharged because. Since I discharge before charging (the packs are cool before charging) the mah reading is always accurate (as accurate as the charger says it is.....) anyway, with 3300s I notice that they often go far beyond 3300 mah while charging....up to 3700 at times. The packs by this time are usually around the 120-130 range. I have found that cutting the packs charge off a little early, say around 3300 exactly produces higher output voltage during the 5:30 range where it is critical to have power for racing. If your just messing around, let them go all the way.
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Old 08-22-2003, 02:36 PM   #10
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Maybe thats the case at your track...but not at alot of others.I would trust the matchers with what they have experienced over your recommendation.Most of the guys who I race with don't cool them.Some of them full factory rides.They are not slow.So whats up with that?
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Old 08-22-2003, 09:53 PM   #11
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Default Cooling Batteries While Charging

racenut123;

Went to the SMC site and no mention of the consequenses of fan cooling while charging. There is one small little mention in the forums by 'Korgae', but other than that I can't find any information.

Just cause the "FAST" Guys are doing it at our track, doesn't mean it's the best way.

I will try it both ways this weekend and see what happens.
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Old 08-22-2003, 09:56 PM   #12
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thanx everybodies

tell me the results ty ty ty
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Old 08-22-2003, 11:08 PM   #13
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Quote:
Originally posted by dasgruvn
thats a good point. I do notice some racers cooling their batteries while charging. Maybe they don't know about hurting the interior of their cells. Also, it is not good to re-charge the battery after running correct? Let them cool for about 10 mins or so correct?
I give my cells about 4 hours between charges, if I even run them twice in the same day. 10 mins cooldown on a NiMH will kill the cell.
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Old 08-23-2003, 09:05 AM   #14
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I'm cheap/poor and run the same pack all race day and I can assure you that running 5x a day with maybe 12mins of cooling time before charging will kill a pack in 6 months.
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Old 08-23-2003, 11:43 AM   #15
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Heat to a pack is not all bad. If they get really hot thats bad but charging should not need to be put on to a fan unless your in Arizona with high heat chaging outside
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