Many of us travel with cameras, laptops, videocams, and so forth that have rechargeable batteries, and also rechargers that can handle any voltage from 100V to 240V. The question is when one is in a hotel with two voltages available (e.g., I am now looking at two outlets, one at 110V, the other 220V), does the speed at which batteries recharge differ depending on which voltage socket you plug the recharger into?

Since sometimes a recharge can take hours, the answer to this question could be very helpful if there is a significant difference in recharge time.

I don't know, but in practice I use 220V for recharging.

Unless the transformer regulates the output voltage, a 220v input would cause it to output twice the voltage of a 110v input. In that case, it would charge faster.