I think the charger can make a difference and typically performance is directly proportional to price. My experience with Eneloops was not particularly satisfactory. They started out lasting almost as long as good alkaline batteries but every recharge cycle got shorter until I was recharging weekly or even more frequently. This was using two Panasonic chargers that came with the Eneloop batteries. I finally gave up on them and reverted to high grade alkaline batteries that I expected to last a month to six weeks in the same device.

Since then I have switched to a Matias wireless keyboard with a built in Lithium battery that reputedly lasts up to a year between recharges (I've only had it five or six months and it is still on the initial charge) and an Apple Magic Trackpad with its own built in Lithium battery that easily goes two to three months between charges. Both of those plug into a standard USB port for charging and have their own internal charge management systems.

If we knew what it was we were doing, it wouldn't be called research, would it?

— Albert Einstein