I need to charge my AA's for my 3 Canon Speedlite flashes before each wedding. I use Sanyo Eneloops and also some older Duracell rechargeable. I was impressed how it could take old batteries that wouldn't recharge in other chargers, and it completely restores them to working order! The 16-bay charger makes it so easy to just dump all the batteries in over night and be ready in the morning for work! I highly recommend this to every professional photographer.