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Old 09-22-2003, 10:32 AM   #1
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Default Battery Problems

Hi,

I am new to the hobby.
Just recently got the CDC charger to charge my batteries.
I got myself 3 packs of cheapie team mind 3000 NiMh batteries.
The first time I tried to charge one of them, I selected 5A, the CDC charger showed over 12V internal battery voltage and shut off!!! How can a 6 batteries 7.2V battery pack has 12 V of voltage!!??
So I tried to charge my 5 cells 750 NiMh at 0.5A, again my CDC charger showed a over 7V even before the charge!! 5 cells!! SHouldn't it be 6 volts?? BTW, I notice large IR measurement on the batteries from the CDC readout.
Can someone tell me what I am doing wrong?
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Old 09-22-2003, 10:38 AM   #2
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With the CDC you need to tell it how many cells you are trying to charge in the set-up. Sound like you are using a program for an incorrect number of cells??? something to check.
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Old 09-22-2003, 10:58 AM   #3
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I did select the number of cells... =(
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Old 09-22-2003, 11:22 AM   #4
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Default Battery Problems

lawndoggie;

The final voltage of any pack will be considerably higher than 1.2v times the # of cells.

I find that my 5 cell nitro packs end around 7.5+ when they're done.
For 6 cell packs, the final voltage depends alot on the Internal Resistance of the Pack and what type of Cell is being charged. With lower quality cells having a much higher final voltage when peaked.
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Old 09-22-2003, 12:30 PM   #5
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hmm all my batteries seem to be running very high on voltage, just charged another 6 pack. Got it up to 11.5V!!!!
And now I am charging my TX pack, its getting to 11.75V and it just started charging!! Also the 2 fans on the CDC chargers are not spinning!! Is there something wrong with the charger?
ALso, when I get a new pack of batteries, should I discharge it before my first charge? Othereise, how do I know how full or empty is the pack?
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Old 09-22-2003, 01:50 PM   #6
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Where do you often play you car?? (this is a alternative question... See I m from HK as well... and see if I know you..)
usually, a output voltage of the charger on most recent GP3300 will be arround 8.9V, some of them will be lower. The main reason for the high output voltage is the high IR (resistence), most caused by some dead cells (what kinda 3000 cells you've got?? Sanyo or Panasonic? where did you got them??). Sometimes one dead cell in a pack will make the charger's output voltage go over 9.5V... But 11V+ is not a usually case... are you sure it is the output voltage or input voltage of the charger??
Have you check if the program is for Nimh or else??
A whole new pack of batteries need to discharge before charge it. In most case, we'll cycle the batteries (discharge -> charge -> discharge) before really start to use it. This action will stablize the condition of the pack.
Well come to PM me for any local question.
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