Hi....I have issue with me yamaha ft9.9 hp higt trust long term. On me boat I have 2 yellob optima battery of 55 and when I power on the yamaha at min of rpm the volts of charge go to 15.6volts I have talk with yamaha and change the managed rectifier however the issue is something very similar, not arrangement. About we how I get done for not have this issue? What the answer for have a right charge voltage of 14.5 max on charge?