Does my outboard charge my battery?

R

renocam

Recruit
Joined
Feb 27, 2007
Messages
2
I am a new boat owner and I have a few basic questions. Please help. Mercury 700 outboard. Serial number 4829602. Does this outboard charge my battery while running? If so, how? Wouldn't that require an alternator? I have two batteries. Should one be solely for the motor and the other for the accessories (trolling motor, downriggers, radio, etc...) or should I wire both together? Any help would be appreciated.
 
Plainsman

Plainsman

Rear Admiral
Joined
Apr 2, 2006
Messages
4,062
Re: Does my outboard charge my battery?

Welcome to iboats!! I can't answer your first question, but yes the second battery can be used for accesories.
 
WillyBWright

WillyBWright

Fleet Admiral
Joined
Dec 29, 2003
Messages
8,200
Re: Does my outboard charge my battery?

And no you shouldn't connect them together, except maybe for a heavy jumper between negative posts. Your motor does charge the battery as long as the components are functioning properly. The alternator is under the flywheel. Magnets in the flywheel combined with the stator under it make electricity separately for the ignition and charging systems. That's connected to a rectifier that changes the AC voltage produced to DC. It will only charge the starting battery.
 
Texasmark

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,953
Re: Does my outboard charge my battery?

You don't have to guess on the alternator. Put a voltmeter on the engine battery with it off and read the voltage. Turn on the engine and run at moderate rpm's. Read the voltage again. If it is the same or slightly less you don't have charge capability. If it is up around 14.5 v you are good to go.

If you don't have a meter, take a 12 lamp, like an automotive parking lamp and hook it to the battery with the engine running and then turn the engine off while watching it. Any change in brightness or not would be your clue....would work best if dark as there won't be a whole lot of difference.

I like to keep my engine and acc batteries separate. Have run my engine batt down before and no fun to start a large OB with a pull rope.

Older outboards, if equipped with alternators (generators) at all didn't have a lot of amperage capacity. My opinion is that you wouldn't do all that much good, trying to keep your acc battery charged with your engine's charger....just my opinion.

Obviously it depends on input and output; recharge capability and discharge.

HTH

Mark
 
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