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1977 merc 50 hp 500 charging system

pilot481

Regular Contributor
Im about to install a dual battery system in my boat. One battery for starting and the other for my trolling motor and other accesories. But now im wondering just what the charging capacity is on this motor. The previous owner had two batteries but they wernt isolated.
I have a wireing mess to clean up but i guess it worked.
 
It isn't much below high r

It isn't much below high rpms. Be sure the battery switch is a make before break design or you'll fry the rectifier.

Jeff
 
"Yes, I'm thinking maybe 9

"Yes, I'm thinking maybe 9 amps at wide open and as Jeff eludes to it's kinda a linear scale - so at idle you may barely squeak out 1 amp.

Most older motors provide sufficient charging power to keep fully charged batteries topped up.

So the nav lights, a fishfinder/gps etc will not put significant strain on the system.

However, they were never intended to recharge a battery that was having many amps sucked from it by an electric trolling motor.

Even a modern 50 will only cough up 18 amps (so you would have to run at wide open for 5 solid hours to recharge a group 27 deep cycle battery) making an on-board charging system that you plug in at the dock the best solution for lower horsepower motors...."
 
"ok, Im convinced [img][/img].

"ok, Im convinced
. Ill give up that idea. Thanks for the info. I can always depend on you guys for help!!!"
 
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