Fast charge capable nimh always means high discharge?

VegasF6

Flashlight Enthusiast
Joined
Dec 5, 2007
Messages
1,449
Location
Las Vegas
I notice now and then nimh batteries for sale, in particular on Battery Junction. Sometimes they say they are safe for fast charging, but don't always give a discharge rate.
Here is an example:
http://www.batteryjunction.com/onepiofcsi50.html
They just say "high rate" and give specs for fast charging (though a 2 hour charge doesn't sound that fast to me).
Can I assume they can handle a higher discharge rate because of that?

Now here is another example:
http://www.batteryjunction.com/propel-yellow-subc4500-tab.html
This battery says it can handle a continous discharge of 10C, but the recomended charge rate is about 1.25C.

So, charge rates and discharge rates don't always go hand in hand?
 

Mr Happy

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Nov 21, 2007
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5,390
Location
Southern California
So, charge rates and discharge rates don't always go hand in hand?
I don't believe there is a strong relationship between them.

For charging, all NiMH cells are basically the same: they are best charged at a rate up to 1C, with 0.3C to 1C being optimal. The exceptions to this are cheap, low quality cells with a high internal resistance, which will get very hot if charged at a 1C rate and are best charged at lower rates.

For discharging, the main limit is the design of the cell and its internal resistance. Cells rated for discharge up to 10C or more have a very low resistance and therefore can deliver such large currents without losing voltage (or getting excessively hot in the process). You can't tell this from charging rates (which are the same for all cells), you need to look at the specific cell's rated discharge rate.
 
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