I am no battery guru and couldn't even tell you how a battery works, to me you slot it in and hopefully they work. Not anymore, now I just put more in and recharge the others, they don't take too long to charge and once charged seem to last a lot longer than most I've used. With 4 teens batteries never last long in our house so they have already paid for themselves in money saved and it's helping our environment, yes I have been educated by the kids on how we need to look after our planet and we are trying to make changes, every little helps.
Inexpensive, do what their supposed too. What's not to like. Would recommend.