Adding alternator for stereo while keeping stator? Mercruiser 3.0

davisboy421

Recruit
Joined
Jul 11, 2017
Messages
1
Hello everyone I'm new to forums and finally bought a water ready boat. It's a 1988 19ft Dixie Swinger with 3.0 Mercruiser 165hp the charging system is currently a stator. I'm wondering if i can keep the stator and add a alternator charging a seperate battery and supplying my stereo. Or if it would be possible to rewind the stator to atleast put out somewhere around 100 amps. I need the extra current to supply 8 tower speakers 4-8 in boat speakers and 2 10" subwoofers. I will have 2 1200watt rms amps and may be adding another. I want to have enough current flowing to keep the radio at 1/2 power cruising. I planned on doing all this on a 98 maxum with a 5.7 and the dual alternator set up on a Chevy 350 is a cake walk but that project is far from water ready. :grumpy:
 

09TNRT

Petty Officer 2nd Class
Joined
Jun 26, 2017
Messages
104
With your proposed setup you're looking at a minimum of a 200 amp alternator just to keep up. I'm fairly new to boats but rule of thumb in car audio which I used to be big in is divide watts by average alternator output. In your case, 2400 rms for the 2 you have is 174 amps at max output assuming 13.8 volt charging. That's not accounting for anything thing else. Add a another amp to it plus all the other things that pull down voltage and I think you'll quickly find your 100 amp alternator will not be enough unless you have a giant bank of batteries. Your amp draw will be more dependent on the music you listen to as well, lower bass notes will take more power to achieve than higher notes so to speak. Look at a car that has a setup similar, when it hits low notes the lights will dim without enough juice.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
51,266
your motor is a 3.7 liter, not a 3.0 liter

I would look into an alternator conversion for the boat anyway as the stator is a known issue (among many on the 3.7)

with all that audio equipment on board the boat, you probably no longer have any capacity for people
 
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