I started work on my boat today, have half the deck out and some other odds and ends done. As I go, I'll make changes to the wiring and will be adding an oboard charger. I've looked at a few onboard chargers ...now my question is about the Amps. All the chargers seem to have the same function basically, but as the Amps go up, so does the price. What's the best 'bang' for the buck, so to speak? I've seen chargers with as little as 8 Amps up to about 20 Amps.