Battery Charging Too High?

[Bartableman7]

1981 Mercury 50 HP 2-stroke:  charges my battery at 17.3 volts.  I replaced the regulator and the coil...same. same.  Should I just leave it or will it burn up the charging battery with time.z

[TnRiver46]

17.3 reading on a multimeter? Maybe try a different battery and see if it does the same. And check the water levels in the battery (I always try the free stuff first )

[Bartableman7]

My Garmin screen shows 12.5 volts while sitting and 17.3 volts when running full speed.  I like your idea...I'll put my multimeter on it too.

[WRB]

Your OB is charging the cranking battery...correct? The meter is connected to the OB alternate output.

Tom

[TnRiver46]

18 hours ago, WRB said:

Your OB is charging the cranking battery...correct? The meter is connected to the OB alternate output.

Tom

Yes but I think that alternate output is supposed to be in the 14 v range

[newbiedmv]

I don't know if the alternator has a current regulator in it to prevent batteries from cooking or it from cooking.

I wrote or emailed mercury with a question "can I rig up a system to charge both batteries on a 12/24v system without frying the alternator when I run the batteries way down"

The answer was "MAYBE", According to them it depends on the serial number.

I decided against it as we did it at work ( 24v mil. Comms) with a separate 24v alternator installed and we fried 3 (100 Amp draw from an inverter...don't ask, I know the numbers don't add up..let's say coffee was being made)

Drop Mercury a detailed email with the year, model, and s/n. They should be able to help.

Oh the system was some ganged switches to put the batteries in parallel and disconnect the trolling motor.

It was a 2005 merc 50hp 2 stroke

Fried 3 alternators and two military batteries exploded in the trucks bay once.