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6V to 12V Generator conversion

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mcashman53
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Location: Madison, VA

6V to 12V Generator conversion

Post by mcashman53 » Thu Jul 02, 2020 10:55 am

I have a 1950 CC Sportsman (18ft) and recently upgraded from a 6V to a 12V generator. The work was done by a reputable shop.
When I start up and get the RPM's up a little, the generator kicks right in and charges around 18V on the voltmeter..sometimes it gets to 20V. After about 10-15 minutes, it drops to zero. I am suspecting a wiring issue since the wires look really old (maybe original), and the extra juice the generator is supplying is too much for the old wires. Does this make sense...or could it be something else? I have polarized it but that didn't make any difference. I also disconnected the battery when the engine was running and it stopped...indicating the battery is running the engine, not the generator. Just curious - How long can a 12V battery run an engine if the battery is fully charged? Not that I want to do that...but I want to know if I'm going to get stranded. Any thoughts?? Thanks-Mike

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drrot
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Re: 6V to 12V Generator conversion

Post by drrot » Thu Jul 02, 2020 12:51 pm

It will run all day on a fully charged battery as long as you don't turn it off. It's the starting and other accessories that really suck the juice.
Jim Staib
www.finewoodboats.com


1947 Penn Yan 12' Cartopper WXH474611
1950 Chris-Craft 22' Sportsman U-22-1532
1957 Chris-Craft 26' Sea Skiff SK-26-515
1968 Century 17' Resorter FG-68-174

mcashman53
Posts: 23
Joined: Mon Jul 29, 2019 1:35 pm
Location: Madison, VA

Re: 6V to 12V Generator conversion

Post by mcashman53 » Thu Jul 02, 2020 2:13 pm

Thanks, Jim. Good to know.

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mbigpops
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Re: 6V to 12V Generator conversion

Post by mbigpops » Thu Jul 02, 2020 4:54 pm

I think you mean 18 or 20 amps. Most of these boats have an ammeter.

Did you disconnect the generator output and measure the voltage coming out of the generator ?

What is your generator output wired to ?

Mark
1953 CC Rocket Runabout "Rocket Man"

mcashman53
Posts: 23
Joined: Mon Jul 29, 2019 1:35 pm
Location: Madison, VA

Re: 6V to 12V Generator conversion

Post by mcashman53 » Fri Jul 03, 2020 10:53 am

Thanks, Mark.. yes, you are right....I meant AMPS. I have not measured the output from the generator yet. Wasn't quite sure how to do that...
The generator has a "cut-out" (silver small box) on top of it with a black wire going into the generator from the cut-out and another wire going from the cut-out to the AMP meter.

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mbigpops
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Re: 6V to 12V Generator conversion

Post by mbigpops » Fri Jul 03, 2020 6:08 pm

I have not tried this yet but at low RPM and cutout relay still open you should be able measure from the generator side of the cutout relay to ground with a meter. Once the cutout relay closes that also closes the circuit back to the battery and you said that you cannot disconnect the battery without the engine stopping.

Do you have a wire that comes back to the starter solenoid (where the battery is connected) from the other side of the ammeter ?

Mark
1953 CC Rocket Runabout "Rocket Man"

mcashman53
Posts: 23
Joined: Mon Jul 29, 2019 1:35 pm
Location: Madison, VA

Re: 6V to 12V Generator conversion

Post by mcashman53 » Fri Jul 03, 2020 6:33 pm

Thanks Mark, I'll try that.
Yes, I attached a picture - I do have a wire from the amp meter that goes back to the starter (red cloth wire).

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mbigpops
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Re: 6V to 12V Generator conversion

Post by mbigpops » Mon Jul 06, 2020 7:34 am

I installed a new battery in my boat and I saw a similar behavior.

I think you may just be seeing that your battery is fully charged after the 15 minutes and just isn't drawing any more current.

Mark
1953 CC Rocket Runabout "Rocket Man"

mcashman53
Posts: 23
Joined: Mon Jul 29, 2019 1:35 pm
Location: Madison, VA

Re: 6V to 12V Generator conversion

Post by mcashman53 » Mon Jul 06, 2020 11:19 am

Well, if that's the case that would be great. Thanks for your help! Mike

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