1973 Mercury 500 thunderbolt questions?

Sacky661530

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Jun 28, 2018
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Was wondering does this motor have a alternator or charging system? I want to put a little stereo in my boat but don't wanna drain my battery. Also wanna make sure it's charged up.
 

schematic

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it likely has a unregulated charging system. best be upgrading it to a regulated rectifier if you want to run electronics
 

Sacky661530

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So is there any way to find out if it charges my battery while it's running at least? And where is this rectifier located?
 

GA_Boater

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Electric start model? If yes, it has a charging system. Put a meter across the battery posts while it's running and the voltage will increase as the RPMs increase.

A regulator isn't needed for electronics. Not the best thing, but the battery acts as the regulator and electronics is tolerant of a range of input voltages.
 

schematic

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A regulator isn't needed for electronics. Not the best thing, but the battery acts as the regulator and electronics is tolerant of a range of input voltages.

true if your battery is in good condition, but as it ages, the internal resistance increases allowing voltage to climb. once you hit 16v - 17v you run the risk of smoke.....just saying. If its a cheap stereo, who cares...
 

jimmbo

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Those unregulated systems don't put out a lot of current even at peak output. In most cases they don't get/keep a battery fully charged during the course of a day. However they do require a Wet Cell Battery that permits the Electrolyte levels to be checked and water to be added. That means NO Maintenance Free batteries or AGM(Optimum) type batteries.
 
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