At present, I am using the following charger and battery for my K-x.
Amazon.com: Duracell Mobile Charger With 2AA And 2AAA Pre Charged Rechargeable Nimh Batteries, CEF23DX4N: Electronics Amazon.com: Duracell Pre Charged Rechargeable NiMH AA Batteries, 4-Pack: Health & Personal Care
This works well for me.
I have mentioned the above link only for reference. You may get this at a better price.
Anyway, I think I should try Sanyo Eneloop AA NiMH Pre-Charged Rechargable Batteries also.
Thanks,
Krishna