+1 to getting a smart charger. When I first got my Vision 1, I went for one of
these sets, which has done well for me (I didn't use this seller then, but I have bought batteries of them since- that's about the best price online for this one btw). Never had any problems with the Camlink batteries either, my run times have been on a par with Ian's and I've bought more sets since. The Camlink charger works well too, but it won't give you the feedback, flexibility, and reassurance that a smart one will. It's two batteries or four, AAs or AAs, one charging speed only (this is as about as fast as they get, not necessarily a good thing though I've had no problems), bad cell detection, and trickle charge when full. That's it. After concerns I had about how some battery sets I had were lasting, plus getting a USB charging pack that took three AAs, I decided to buy one of
these. Which is absolutely brilliant (alternative options available from various places). By all means get a decent more basic charger to start with, but if you get one of these that'll stay in the cupboard. Any number of batteries from one to four, in any combination of AAs and AAAs, and if they're different capacities, differing charge levels, not a problem.