Nikon d5100 travel adapter?

I just recently bought a Nikon d5100 and was planning on taking it overseas to America in November. I was wondering where i might purchase a power converter or travel adapter or whatever they're called, so I can recharge the rechargable batteries that came with it. I'm not actually I'm suppose to use one with the camera because in the manual it says not to? Which I thought was weird because how else am I suppose to recharge the batteries while I'm in America if they run out of juice. I understand that they run on a different voltage or something over there that's different to here in Australia.

Your Nikon MH-24 charger should be able to work at 240V (Australia) or 120V (USA), but if it has an Australia plug you will need an Australia to US Plug adapter. It's probably best to buy that in advance of your trip.

GTMax EN-EL14 Battery Charger with Car Adapter for Nikon d5100… This item is very handy when traveling and it works very well. Recharge times are quick and it works both in a regular electric outlet and in a car.