Motorola V600

My friend's v600's battery is always dying because he's lazy and doesn't charge it. :-) I was going to buy another battery for him, but I need to know:

Does the charger that comes with the phone allow you to charge a battery without the phone? Does anyone have one that does? I'd like for him to be able to leave one battery charging, while using the other one with the phone.

Thanks - I hope.