habbi wrote:

Could I use NiMH in place of my NiCad?


Offhand, I'll say yes, with a big (BIG) "but".

The "but" is that you will want a new, suitable, charger. Or you will
have to be willing to eat the cost of a couple battery packs learning
what fries them.

Possible, but not real practical unless you are willing to spend.

http://www.rccaraction.com/articles/NiMHbatcare1.asp has a bit of info,
geared towards the RC car guys, who tend to run their batteries down
then recharge immediately.

Cheers
Trevor Jones