Battery Reading 17 volts at WOT.

[aussieflash]

Gday all,Running a V6 Merc 88 model.Newish Marine battery working well.On fishfinder showing battery volt reading at around 12.8 with engine off.Running it shows increase volts to approx 13.5,but when near WOT yesterday it showed 17.0 volts.Is that too high or is it normal?
Thanks for any help.
Paul.

 

[Don S]

Re: Battery Reading 17 volts at WOT.

You probably need a rectifier/regulator for whatever V6 Merc you have. Anything over 14.8V is going to boil all the water/acid out of your battery in no time. Then you will need another new battery.

 

[MH Hawker]

Re: Battery Reading 17 volts at WOT.

17 volts Yikes

 

[aussieflash]

Re: Battery Reading 17 volts at WOT.

OK ill check direct to battery volts and see if different reading.My outboard has a rectifier but no regulator and in my merc service manual it states this is UNREGULATED.charging system.
Manual states: Recommended Battery of 350 CCA (min) and "Reserve Capacity"of 100 minutes (min) to absorb the unregulated battery charging power.

 

[aussieflash]

Re: Battery Reading 17 volts at WOT.

Any thoughts on this??As I understand it,all the rectifier does is convert alternating volts from stator to direct volts to battery.
Could only check battery with engine off last night and read 12.8 Volts.

 

[NYBo]

Re: Battery Reading 17 volts at WOT.

You could add a regulator fairly cheaply. Search this forum area for threads on the subject.

 

[Fed]

Re: Battery Reading 17 volts at WOT.

17 volts is normal for an unregulated system when the battery is fully charged.

You should have a battery with removable caps so you can top up with water from time to time & a bigger battery would help pull the Voltage down.