NiCad/NiMH charger question

I know an NiMH charger can also charge NiCad cells, but can a Ni-Cad charger also charge NiMH cells. Specifically, I am thinking of the Ni-Cad battery pack of a Dremel tool. It is rated 7.2v, and there are four cells wired to provide 3.6v and 7.2v for two speed operation. I would rather not replace the existing cells with more Ni-Cad, but with either NiMH or a LiPo battery pack. If worse comes to worst, I will just wire in an external jack and make up an external Li-Ion pack with a medium length cord.

Forgive me for what may seem like a ****head response but I feel you may want to go do a bit more reading before jumping into battery packs given the info you have provided. IIRC NiCad batteries are 1.2v(nominal) so 4 would not give you 7.2v for that you would need 6. If you've pulled it to bits and see 4 batteries in 2 pairs then you are most likely looking at a 2s2p configuration which gives you 2.4v and then a doubled capacity. NO manufacturer in their right mind you make a battery pack where 2 batteries are used for low speed then 2 others as 'switched on' in series to increase voltage, this would cause all kinds of charge and discharge issues and probably result in very imbalanced over charged/discharged cells. I've had a couple of older battery operated dremels and they were 2.4v and worked aswell as an ant pissing in a water wheel. The cost of making yourself a new pack for this would probably be as much as buying a new dremel. If it has sentimental value then just restore it to OE condition box it up and store it. Otherwise scrap it, ****ing around with batteries (especially Lipo's) is ill advised. Sorry to **** in your parade but I'd rather you go away a little disheartened than go away and blow some fingers off.

Hello Timothybil,

Yes you can charge a NiMh battery on a NiCd charger BUT...

The charge termination on NiCd is a little higher than required on NiMh so you will tend to overcharge and overheat the NiMh battery.

Tom

SilverFox said:

Hello Timothybil,

Yes you can charge a NiMh battery on a NiCd charger BUT...

The charge termination on NiCd is a little higher than required on NiMh so you will tend to overcharge and overheat the NiMh battery.

Tom

Click to expand...

Thanks. I kind of figured there would be something like that. As was pointed out to me, it does not make economical sense to rebuild a Dremel battery pack, especially when one can get a new one for about $20.