I don't normally hawk gadgets, but if you don't have one of these already, get one.
Pearstone Compact Charger for BLM-1 BatteryWhy is this so great, you ask?
1) AC plug is attached and swivels-in to hide
2) Includes 12-V car power port adapter (input)
3) Includes USB charging port (output)
4) and the coup de grace, is that you can get interchangeable plates for almost any DSLR battery
Mine lives in my car or my travel bag and is used more frequently than the original one from the manufacturer.