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HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › Charge rate 2650 NiMh cells
03-07-2008 11:25 AM  10 years agoPost 1
KarbonBird

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Australia

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I have got 4 x 2650 mAh rechargeable NiMh batteries that I want to charge with a Swallow charger.

What is the Amp rate to do this safely and what is the formula for NimH batteries i.e. 2 cells @ 2650 mAh should be charged at X rate , 1 cells @ 2650 mAh should be charged at X rate etc.

TIA

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03-07-2008 12:08 PM  10 years agoPost 2
Dr Lodge

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Guildford, Surrey - UK

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Depends on the cells and the configuration. NiMH do not charge well if in parallel, I assume these are in series to give 4.8 volts?

I would try charging at 1C, around 2.5 amps. High discharge cells can take more, 1.5-2C.

Vibe 90, Vibe 50, Vigor CS x2,
Dyna-x, Knight 503D, Logo 10,
TRex 500, Furion, Gaui EP200

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03-07-2008 12:25 PM  10 years agoPost 3
KarbonBird

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Australia

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These are just loose batteries that you buy at the local store - will be used to power an onboard camera.

I have placed them in a plastic battery holder pos to neg x 4.

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03-07-2008 01:09 PM  10 years agoPost 4
Dr Lodge

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In that case they are in series, and the charge rate in amps is the same irrespective of the number of cells - its the voltage output by the charger that will be different.

If they are new cells they need to be conditioned. That means charging at 0.1C (250mAmps) for around 16 hours. If the charge rate is lower, then extend the time proportionately. A few discharge/charge cycles after that should show the capacity of the cells increase.

I use the 0.1amp charge rate on my charger for conditioning, since the charger never cuts out at that setting. Your cells would need 40 hours at that rate.

Vibe 90, Vibe 50, Vigor CS x2,
Dyna-x, Knight 503D, Logo 10,
TRex 500, Furion, Gaui EP200

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03-07-2008 09:42 PM  10 years agoPost 5
KarbonBird

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Australia

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Many thanks for the feedback - I will start them off on an overnight charger to get the ball rolling...

Once conditioned - would one not charge them at 1C i.e. 2.65 A?? I have tried 1.7A and they seemed to get a bit on the warm side.

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03-08-2008 01:49 PM  10 years agoPost 6
Dr Lodge

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If there are getting warm at 1.7 amps then charge them at around 1.5 amps - the current they'll take depends on chemistry and construction.

What are you going to use these cells for?

Vibe 90, Vibe 50, Vigor CS x2,
Dyna-x, Knight 503D, Logo 10,
TRex 500, Furion, Gaui EP200

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03-10-2008 01:25 PM  10 years agoPost 7
KarbonBird

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Australia

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for a digital camera...

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HomeAircraftHelicopterRadio - Servo - Gyro - Gov - Batt › Charge rate 2650 NiMh cells
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