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Yamaha F90 Charging Voltage
Posted: Sun Mar 06, 2016 10:07 am
by C_M_25
Hey guys. Got the boat out on its maiden voyage for the season yesterday. Everything ran fine; however, my voltmeter on the dash was reading just a hair under 15v regardless of motor RPM. That seems pretty high. I don't recall it running that high in the past. Two weeks ago, I got her out just 20 yards away from the launch before I noticed strange electrical problems. Turns out that I had a group of ground cables that got tucked back behind the batteries and weren't hooked up. The main cables from the motor were hooked up, however. Could that have fried the regulator? What kind of voltages do you guys see out of your boats when running? Thanks
Re: Yamaha F90 Charging Voltage
Posted: Sun Mar 06, 2016 2:44 pm
by illinoid
I wouldn't be too concerned unless you run it hours at a time...watch your water level in your batteries. Could be the guage reading a little high also, a hand held volt meter across the battery would tell you.
Re: Yamaha F90 Charging Voltage
Posted: Sun Mar 06, 2016 6:21 pm
by C_M_25
Well, I put the voltmeter on the battery, and I was getting 14.7 pretty consistently regarding motor rpm. The console is getting 14.8. Not sure why it is different but probably just splitting hairs honestly. I still don't like that it is a consistent voltage regardless of motor rpm. Seems like the motor should be sending less voltage if the batteries are fully charged?
Re: Yamaha F90 Charging Voltage
Posted: Tue Mar 08, 2016 2:14 pm
by rancherlee
Sounds like it's doing is job, with low draw and full batteries it possible to peak the regulator. Anything from 13.6-14.7v I consider "healthy" regardless of RPM.
Re: Yamaha F90 Charging Voltage
Posted: Tue Mar 08, 2016 6:17 pm
by illinoid
With the battery fully charged the voltage will be the same at any rpm. When it is partially discharged higher rpms will give you higher voltage up to the max the voltage regulator will allow.