I have a trophy 1802 with a Merc Saltwater series 125 outboard uses a stator and not an alternator. It says that it produces 17 amps at WOT. Is this enough to charge two batteries? I have 2 now and I'm looking to replace them because they are 5 years old and they don't hold charge as well as I would like. Can I go to 27 series batteris? I believe they are 24 series right now. If the motor can't handle charging the bigger battery it might actually be worse than a waste of money. Thanks for any input. My trips are usually within 5-8 miles of my marina so I don't get a lot of run time to charge. There is a nowake zone so I guess its running for 20-30 mins to get to fishing grounds.