In the past I've always used the Battery Tender mentioned above but it is slow as the output is only just over an amp. This is good for standard flooded lead acid but that is all that it can do. I picked up a Noco Genius 10 a few months back. It has the ability to handle several different battery types, standard flooded, lithium, and AGM which I like a lot as the different makeups require different amp charging rates for the best charging. So far, its been good. I bought the quick disconnect leads as well for several of the batteries. There is a battery restoration feature but I haven't tried it yet.