I'd also recommend an external charger - with one caveat. You need a good charger. Using a good external charger is better than charging in the mod, but it's better to charge in-mod than to use a bad external charger.
Xtar, Nitecore and Efest LUC chargers are reasonably priced, decent quality devices. They aren't the only good brands, but I'm not as familiar with them and they tend to have extra features (good if you understand them, but not necessary) and higher price tags (not so good).