Yamaha FT9.9 LEPL 2014 high trust + power tilt --- HELP me please

[ricciola73s]

Dear friends, i have buy an new yamaha FT9.9 LEPL that have electrict startet with power tilt and high trust propeller.
Me big problem are that this outboard at min rpm recharge the batteri with 15.8-16 volts and give mor eproblems to me batteries. i have test if are the rectificher-regulato with an new genuine yamaha part but i have same result of 16volts on charge at min of rpm of the motor.
i not have any problems with me old F9.9A high trust, for 10 years, but after i have buy this new outboards i have many problems.
The yamaha assistance of me city not need the problem and not have any idee how resolve this big problem.
also i have buy 2 new optima yellow battery because me old battery are demaged from big charge of this yamaha outboard.
Please help me how i can resolve this problem.
the charge range on volts of the rectificher-regulator yamaha of me 9.9 on what range are perfect running??? i think that all regulator not is possible that charge at more that 14.5 volts.............. what do you think.
thanks to all for your attention.
regards
Claudio

[boscoe99]

What you are describing, unfortunately, is completely normal for the type of motor that you have. The output specification is 15 volts. Having a bit more voltage than that is not abnormal.

Even though the output is 16 volts I would not expect that there is sufficient amperage output to damage a battery. Particularly for the relatively short amount of time that an outboard is running.

What some have done to get the voltage down a bit, is to connect a number of lights to the battery. Turning on the light(s) will lower the voltage. But some of the current will be wasted to operate the lights. There is no free lunch.

[ricciola73s]

thanks for your reply, i not understand how is possible that the outboard charge at 15volts.... i have test an othe outboard same the me FT9.9 same year and charge at 14,7 volts at same min. rpm of motor. I use me outboard for professional fishing charter and the motor are runnung for 10 ours at days for *****ing fishing at min. rpm of range.
the charge at 16 volts demage the battery, this is that have talk all tecnic of nautical assistance that i have ask for this problem.
i not understand how is possible that i i use a generic acid battery of 80A it charge at 15 volts and if i use the optima yellow battery it charge at 16 volts?
the optima tecnic assistance talk me that not good charge more that 14.5-14.7 volta for all battery.
please help me for ha solution

[boscoe99]

Isn't the Optima an AGM type lead acid battery? If so, I would buy the largest deep cycle type flooded lead acid battery and try that.

Another option might be to find an aftermarket voltage regulator and connect it to the output leads of your lighting coil to see if it will provide a lesser voltage.

Or, as I said, connect some lights or other electrical load consuming device(s) to the battery that you have and I suspect that it will draw your voltage down.