Have you tried the Energizer rechargeable Ni-MH batteries yet?
If not, I strongly encourage you do try to them. They work great and recharge fast! I have the Energizer 15-minute charger and it is fantastic! When you load the batteries and then plug it in, you hear the fan blowing to keep the unit cool. The batteries charge in no time which makes using rechargeable batteries a great option now.
I was using some other rechargeable batteries for my speedlight but they require overnight charging. This is much different than the short 15 minutes to charge the Energizer batteries. So I plan on replacing these older batteries with the Energizer batteries. Besides, then I only have to carry one charger along with me, too.