Probably better off with a battery powered one where you can either use alkaline or rechargeable.
Oral B Advance Power 400 Battery Powered Toothbrush Powered BY Braun | eBay
The normal rechargeable toothbrushes use induction to charge and its an inefficient and slow way of charging.
We carry around a set of AA Eneloop batteries and use a 12v charger to charge them on the go and its very quick.
Cheers
Mark

