Why VB manual says “Do not use NiCad batteries” ?
What about NiMH batteries ?

Probably because those old style batteries could leak and destroy your battery compartment. I use GP Powerbank NiMH rechargables with no problems.

I assume it’s actually because NiCads only have a voltage of 1.2V, which will only output 7.2V (as opposed to 9V from 6 Alkalines)… so even though the batteries may have plenty of charge left, the voltage of a half dead NiCad won’t be able to keep a VB running, when an almost fully dead Alkaline could still run the VB (the voltage regulator probably drops out somewhere between 6 and 7 volts).

DogP

This may result in failure or it’s just a matter of batteries life ?

Just battery life… people will complain that they’re getting very little play time on rechargable batteries, and it’s very possible that the low battery light will come on in just a few minutes.

DogP

2800 mAh NiMH AA batteries seem to last long enough : several hours of play time (cumuled in one month) and still no flashing low batteries light…