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Old May 4, 2009, 10:21 AM   #1
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whatis the bestdischarge ma rate to use for discharging AA batteries is 1000 to high to use as a discharge MA rate or is it better to use a low discharge rate like:angry:

:bye:..........:idea:.any suggestion would be helpful...?....:P.....:roll:...

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Old May 8, 2009, 2:01 PM   #2
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I go by the .2C rule. Multiply the rated capacity of the cell by .2 and use that for your discharge rate. For 2000 mAh cells, I would use a 400 mA discharge rate.
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Old May 31, 2009, 3:27 PM   #3
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Another good way to discharge is to discharge them at the same rate as the camera will do it
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Old Jul 21, 2009, 6:57 AM   #4
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C/5 is the standard used to duplicate the factory test result, like EPA test protocol for fuel economy.

1A is the best for testing batteries for digital cameras in my personal opinion. Cameras usually draw close to or more than 1A and healthy NiMH will sustain ~1.2v at 1A. Those that drops to 1v can't deliver the current and should be discarded. They still hold the capacity. It's sort of like a fuel system with full fuel, but badly clogged filter.

In a car, it will stumble or stall when you hit the gas. In a camera, you'll get "replace battery" when it tries to charge the flash and shuts down.

The capacity is irrelevant if the batteries are not capable of providing the current the camera demands within an acceptable voltage drop.

Last edited by itsme000; Jul 21, 2009 at 6:59 AM.
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Old Jul 22, 2009, 3:40 AM   #5
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'shoebooty', if you're designing a battery tester, see itsme000's reply above.

If you need to know this because you're designing an electronically controlled discharger with an end point, that's fine.

On the other hand, if you're just aiming to discharge batteries through a resistor from a starting charge rate, until they're empty, be aware that completely flattening any rechargeable battery is likely to do it irreparable harm. You must set a voltage cut-off point below which you never take it.

Last edited by Alan T; Jul 22, 2009 at 3:45 AM.
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