When it comes to chargers, you want to get a smart charger (chargers with built-in protective circuits to control charging). Tenergy has smart charger models if you want to stick with the brand, but there are lots of good models out there. Rapid chargers and "dumb" chargers (without protective circuits) work, but will reduce the lifespan of the batteries.
Smart chargers let you maximize the life of your batteries and in many cases can refresh them if they start to under-preform or lose capacity to hold a charge. My smart charger revived my oldest rechargeables that had almost become useless due to the "dumb" charger they came with. I have been exclusively using rechargeables now for over a decade, and I've only had 3 batteries that couldn't be revived. Personally, I use Eneloop (by Panasonic) batteries, but if you look at comparisons, most brands perform about the same these days. The only real down sides to smart chargers is that they take a little longer to charge batteries, and refreshing a degraded battery can sometimes take 24+ hours in a smart charger to revive, but neither of these matter much if you have charged extras on hand.
Andy
