A friend recently bought me a battery charger which will charge 1-2-3 or 4 batteries. It will also charge alkaline batteries up,to 10 times
I find it very useful for when I have used 3 batteries in my GentLED and for the little camera I use for the video downlink. (Which went faulty after Easter ) :-((
I had 3 alkaline batteries in it for the photo. The levels gradually fill up at their own rate and it turns off when they are all fully charged.