View Full Version : Alternator project is finished

06-07-2005, 09:33 AM
It all started when I installed my accessories. ( radio, two amps, tower lights, and two jabsco ballast pumps)
My original volt meter was giving a low reading all the time. When the battery was fully charged it would show 11 volts. When I turned on the pumps, played the radio loud, or turned the lights on it would drop to about 8 volts.
I re wired my amps, tower lights, and pumps with 6 gauge wire from the battery. ( if I had to do it over again, I would run a 0 gauge wire or larger from the battery to a distribution block closer to the dash)

I still had concerns with the output of the alternator, and how long the battery would last if sitting listening to the radio.

I installed a second battery. The aux battery is a optima blue top dual purpose. I also have a battery isolator. Stinger makes them fairly cheap. they are water proof, and U.S.C.G approved.
With the isolator: when the key is off. The radios, amps, and other toys are draining the aux battery. The original battery is not being used, and is there when you get ready to crank the boat.
When the key is turned on, the isolator engages, and while running the alternator is charging both batteries.

I was not sure the original alternator would charge both battories sufficient. ( turned out it would ) but I found out I had a non marine alternator, so I bought a marine 100 amp Delco one wire alternator off e-bay ( $100.00 after shipping ) Looks new, but is probably rebuilt.
I ran a 2 gauge wire from the alternator to the battery. I fused it with an ANL fuse holder ( e-bay ) it has a 100 amp fuse and is waterproof.

I purchased a second volt gauge for the aux battery. To fix my original gauge. it was losing voltage through the daisy chained wiring. I ran a 10 gauge wire from the switch to the original gauge.
Now My orginal volt meter is working fine.

End result is : when idleing My gauges show 13 volts, when running at higher rpms, it is close to 14 volts.

So far I have not come close to killing the blue optima when sitting playing the radio. ( three hours at faily loud volume )

Hope this helps someone. Thanks for all the information form the forum.

Sorry for the long post too.

06-07-2005, 05:34 PM

06-08-2005, 07:14 AM
This helps alot since I am in the middle of installing the amp, lights, and other accessories. I was considering installing a larger alternator since I already have the second battery with the isolator.


07-06-2005, 07:16 PM
This is great. I am starting the same project on my '94 205 this fall. Tower, Tower speakers, amp and sub so I need to upgrade the electrical system as well. Post some photos of the project if you get a chance.

Great post.