Can a Nicad charger be used for NiMH batteries?

[SimonP]

Hi, I'm new to this site. I have some NiMH AA batteries for my camera. Can they be charged with my old Nicad charger? I've tried it, but the charge doen't seem to last long. Have I not charged them enough, or charged too long and damaged them?

 

[neon]

not all chargers or battery are created equal. ltium is the hardest to charge

 

[SimonP]

What's Itium? - is it the same as Lithium (with alcohol added)? This is a serious question about Ni-Metal Hydride batteries in a Nicad charger - I'm not sure we're on the same page here!

 

[Resqueline]

The answer depends on the complexity of your old charger. It might be non-timed, timed, or a fast charger with negative delta V termination. The last one is not at all suited for Ni-MH batteries which needs a more neutral delta V termination as well as a sufficiently high charging currrent in order to achieve a reliable charge termination.
With the first two you'll need to calculate the neccessary extra charging time, due to the much higher capacity of the Ni-MH technology. If your batteries are 2000mAh then you'll need to charge them four times longer than their 500mAh NiCd counterparts.
If your batteries lose their charge by just lying unused for a week or two then they might be damaged or worn out, and there's nothing to do about it other than charging them immediately before use.

 

[SimonP]

It's a basic Radio Shack NiCad charger that would normally take 18 hours to charge 500mAh batteries. The NiMH batteries are new so I guess I just haven't charged them long enough. I'll check the charging current next time I put them in, and adjust the charging time accordingly. Many thanks for your help.