NIMH replacing NICAD

An off flashlight question. I was going to replace the batteries in a handheld vaccum and was wonderring if I could use NIMH instead of the NICADs that it came with. It is wired with three Nicad KR-1800SCE's in line, and was wonderring if I could substitute NIMH of similar voltage?

Will they charge in the factory charger and do I have to worry about overcharging? Will I get better performance?

It is an old Hooover wet/dry vac if it matters.

If this works, I may do the same with a hand held shaver I have too.

Thanks for the help

Most likely NiMH batteries will not be compatible with the original charging circuit. If you use NiMH batteries they will likely work at first but then fail too quickly and have a short lifespan. It would be best to stick with NiCd cells.

The good news is that some fresh nicads will seem awesome compared to the old. Maybe even higher MAh.

Nicad it is. Thanks for the advice