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generally confused with charging

generally confused with charging

Old 03-13-2004, 09:40 PM
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Ooj
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I need some opinons of charging temperature for gp3300. How hot is too hot when the cells peak? I have played around with using fans, different cutoffs and I have got some very wierd results such as:

On 5 old packs using 30mv/pack cutoff, they will all peak around 3400mah with or without a fan. However, without a fan they will be scalding hot, the IR is stupidly high and feels like it loses a lot of punch on the track

On my new packs, using the same settings, they are taking in 4000-4200mah without a fan and are no where near as hot - they are still good to hold in your hand - the performance is so much better!!

So the question is should I be using a fan or not? Or should I charge my new cells differently to the old cells?
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Old 03-13-2004, 10:44 PM
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Sounds like your old packs are toast. Packs take alot of abuse in there life time and the new nimh cells arn't nearly as resiliant as the nicd's of the past.
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Old 03-14-2004, 08:49 PM
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I have some gp3300. Thay take about 3900 each charge. I discharge at 20a after each run.

They don't get very hot when charging and they are not that hot after a 5min run.

There is a big difference between these and my old cells.

what amps are you charging at and what delta peak.
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Old 03-15-2004, 03:13 AM
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Now that I have used the packs a bit more - its about the 5th cycle - they seem to be taking in less charge. Its closer to 3800-3900mah and the final peak temperatures have gone up by 10 degrees.

I am still using the same methods for charging - I start by discharging at 20A to 4.8v on the CDC and then traying to 0.9v/cell, charge at 5A with 30mv cutoff

Last edited by Ooj; 03-15-2004 at 03:26 AM.
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Old 03-15-2004, 04:09 AM
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Just wondering why you discharge to 4.8v and not 5.4v??? (I'm assuming that these are 6cell packs.....)
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Old 03-15-2004, 04:13 AM
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The CDC charger in discharge mode sets the level to 4.8v/pack. This is no big issue as there is no real difference when discharging at 20A to 4.8v or 5.4v per pack - I use an equalising tray anyways so that will take the cells down to 0.9v individually at a much more gentle and accurate rate than the cdc at 20A
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