However, these batteries need a special type of charger! You can't just use a NiMH or NiCad battery charger, even a LiFePo charger wont cut it. Instead, a proper Lithium charger is required.
Charging is performed in three stages: first a preconditioning charge, then a constant-current fast charge and finally a constant-voltage trickle charge to keep the battery topped-up. The charge current is 100mA by default, so it will work with any size battery and USB port. If you want you can easily change it over to 500mA mode by soldering closed the jumper on the front, for when you'll only be charging batteries with 500mAh size or larger.