NiMH vs. NiCAD charging

[Engineer]

Hi, SED's
I have a Radio Shack battery charger that takes a dozen or so AA NiCAD
cells and a couple of 9 volt NiCAD batteries as well - very useful
unit.

Can I use it to charge the AA size NiMH cells specified for my digital
camera?

Just how different is the charging circuit for these two types of
cell. Obviously I want to retire my NiCAD's and use the more
efficient NiMH's but I'd like not to have to replace the charger.

Thanks for all replies

Cheers,

Roger

 

[Leon Heller]

Hi, SED's
I have a Radio Shack battery charger that takes a dozen or so AA NiCAD
cells and a couple of 9 volt NiCAD batteries as well - very useful
unit.

Can I use it to charge the AA size NiMH cells specified for my digital
camera?

Just how different is the charging circuit for these two types of
cell. Obviously I want to retire my NiCAD's and use the more
efficient NiMH's but I'd like not to have to replace the charger.

NiMH cells can be charged at C/10 (about 14 hours) the same as NiCds. If
your charger is this type, it should be OK. If it is a fast charger, I
wouldn't use it for NiMH; you will need to replace it.

Leon

 

[Engineer]

(snip)

NiMH cells can be charged at C/10 (about 14 hours) the same as NiCds. If
your charger is this type, it should be OK. If it is a fast charger, I
wouldn't use it for NiMH; you will need to replace it.

Leon

Does anyone know the recommended MIN, MAX and AVERAGE charge rates for
2300 mAH NiMH cells? The above RS charger seems to put a steady 50 mA
into a charged NiCAD. I've not tried a NiMH yet but I have 8 NiMH's
on mail order via eBay.

Tks,

Roger

 

[Dave VanHorn]

Does anyone know the recommended MIN, MAX and AVERAGE charge rates for
2300 mAH NiMH cells? The above RS charger seems to put a steady 50 mA
into a charged NiCAD. I've not tried a NiMH yet but I have 8 NiMH's
on mail order via eBay.

NIMH varies widely.
Typically, 0.5C to 2C charge rates are reccomended. Less, or more than this
means you may not be able to detect end of charge. Continuous unterminated
charging (the old C/10 for nicads) is not reccomended for NIMH cells.