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16 volts?

Bull

Bull

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Folks,


I have a Yamaha 150 with 3 yrs on it and two batteries.


When I put it in the water I see she is drawing 16 on the gauge.  When I tested the batteries they tested "ok" .  The voltage when not running is showing 12.5 on both and when at idle the volt meter shows 14.5


My question is ......is 16 volts when running compensating for "ok" batteries and is 16 to high.


i am pulling the batteries out to fully charge them, but any insight is appreciated.


thanks,


Al
 
Bull said:
Folks,


I have a Yamaha 150 with 3 yrs on it and two batteries.


When I put it in the water I see she is drawing 16 on the gauge.  When I tested the batteries they tested "ok" .  The voltage when not running is showing 12.5 on both and when at idle the volt meter shows 14.5


My question is ......is 16 volts when running compensating for "ok" batteries and is 16 to high.


i am pulling the batteries out to fully charge them, but any insight is appreciated.


thanks,


Al
Click to expand...

Sometimes if the batteries are low the voltage regulator on the motor will put out a high voltage. Either that or maybe the regulator is gone. Shouldn't be 16 volts.
 
Tom,would it be normal to draw 16v if batteries are low?


thanks
 
Double check voltage with a meter. Gauges can be sporadic for accuracy. I'd say 16v is high, but verify it. I think they typically charge around 14.5 volts. 
 
It's difficult to debug this without a little in person troubleshooting. I agree with Semperfi, I wouldn't trust a dash gauge at all, so verify that. If it truly measures 16v on a multimeter, something is wrong.


A really low battery (10v) normally won't even activate the alternator. When running properly the alternator normally shouldn't try to put out more than 15v to run electronics and charge the battery.
 
Outboard motors have a rectifier to control voltage because the motor produces AC current  so it needs to be converted to DC to charge your batteries, If the motor is putting out16 volts, your batteries won't last long. I speak from experience.
 
Thanks guys,


On the meter it is pulling 14.5 but that was at idle.


Is it common to pull more when revs increase


Thanks for all the help
 
Depending on the gauge type you can just cross the terminals and if it pins the gauge  it's junk. I'd check the bot at idle and at some RPM and see what you have. Make sure your using the wiring going to the battery and not the terminals you can get different readings if your battery has a bad cell, we chase this all the time on our electric scissor lifts
 
Bull said:
Thanks guys,


On the meter it is pulling 14.5 but that was at idle.


Is it common to pull more when revs increase


Thanks for all the help
Click to expand...

Pulling 14.5 is not normal at idle, that is exactly what mine did. As rpms increased the voltage went to 17 volts. I had a fish finder that verified the voltage on the amp gauge was also 17V. The rectifier is easy to change, it is basically a plug in application, the part can be pricey. I had a Mercury that was made by Yamaha, the Mercury Part cost $550, but thanks to the internet I found the equivalent Yamaha part for half the price. 
 
I had the tech look at it today.


it was pulling 14.5 volt at 2k rpm......he said it was good and just trying to charge the batteries.  This weekend I am going to pull them and make sure they are topped off and see what it draws
 
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