NiCd Battery charging at C/10

Apr 21, 2006 3 Replies
S

I need to charge a 300mA-h 3.6V NiCd pack using solar module giving out



4.2V at 30mA short circuit current.

So we're C/10.



I intend to connect the solar module in series with the battery using a low drop out shottky diode.



First, do I need overcharging protection circuit at C/10 rate?



What are the cons of not using overcharging protection circuit at C/10 rate?



Next, will the scheme work, since it would take 3 days to fully charge the battery (assuming 6 hour daily sun exposure) ?



Any help would be greatly appreciated.


- Mike


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L

You dont need the diode, or anything else for that matter. Connect the solar module directly to the battery. Solar modules voltage will drop down to the battery voltage at the maximum current output. At C/10 there is not much problem with overcharging either.

Luhan

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S

I was wondering what would happen to the solar cell junction at the time of no sunlight in case we don't use the diode as you advised ?

(Would the junction act as a diode / cap in series with the battery?)

Also at C/10 it would take 3 days to charge the battery.. Is such charging in "batches" acceptable to the battery?

Thanks Mike

Luhan wrote:

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L

There can be a slight drain back thru the solar cell under no-light conditions.

Yes.

Luhan

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