charging both batteries off of a Merc 50 HP

dbergman

Seaman Apprentice
Joined
May 4, 2006
Messages
34
Is my 4 cylinder 50 merc going to be overly taxed to run in the Both position on the Perco switch? I'm thinking to run off of Batt 1 or 2 only once I arrive at the spot I use my trolling motor and then switch back to both position to start and run the 50 hp motor.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: charging both batteries off of a Merc 50 HP

Nope, no harm! You can't get blood out of a turnip and the same logic applies to an alternator. The batteries can only accept what the alternator is capable of giving them. If alternator maximum output is 15 amps, that's all the batteries will get.
 

dbergman

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May 4, 2006
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34
Re: charging both batteries off of a Merc 50 HP

Would it be best to start and run in the both position and then select bat one or two while trolling, or should I start and run on bat 1 or 2 and then switch batteries to trol? which will give me better battery endurance?
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,778
Re: charging both batteries off of a Merc 50 HP

Only problem I could see would possibly be overheating of your alternator. Continuous heavy charging could do that and there aren't any fan blades under the flywheel (like the front fan on a car) to help to cool the windings.<br /><br />Last time I bought an alternator from AutoZone, the first thing they said was to not put it on a discharged battery (or void the warranty)......now this is for a car and it of open construction and has a fan.....why? Because of the length of time high current would be flowing could overheat the components.<br /><br />Probably the biggest thing at risk would be the rectifiers that convert the ac of your alternator to dc that your battery needs. They get hot and fail. The cores and magnetic windings of the alternator it'self usually tolerate higher temps that would fail a silicon diode.<br /><br />Mark
 

dbergman

Seaman Apprentice
Joined
May 4, 2006
Messages
34
Re: charging both batteries off of a Merc 50 HP

Thanks for the info. Sounds like I aught to just start and run on one and then switch to the other for the trolling motor.
 
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