I would suspect that their warning pertains to theirs charger. The NiMH
batteries have a slightly different charging behavior than the NiCad.

Why don't you purchase set NiMH batteries and one of the 'smart' battery
charges, designed for both NiMH and NiCad..

Intially, when I switched to NiMH batteries, I was very disappointed with
their 'shelf life' (self discharge). However, once I got a smart charger,
I'm very happy with the NiMH batteries.


--
My opinion and experience. FWIW

Steve
s/v Good Intentions