Hey Guys

I am looking at replacing the alternator on my 454EFI powered Baja this winter, the "stock" alternator has seen better days, and I have added some extra stereo stuff, and some lights, so, I would like to upgrade over the 55? amp alternator that it came with [its also 15 years old]

My question is: my current alternator has 4 wires [1 large red, 1 small, and 1 large black and 1 small] the newer alternators I have looked at ALL either have 1 wire, or 3?

What is the "other" wire for? Can I use a 1 wire [or 3 wire] set up? if so, How would I go about hooking it up?

I have asked a few guys locally, but, no one seems to know anything about a 4 wire set up, the boat is stored for the winter now, so, I dont have the part number, but, I believe its the stock "Mando" GM style alternator that came on the boat originally. I believe its internally regulated and it uses a "V" pulley, not serpentine.

Any Input would be appreciated!

Michael

I've attached a download of what I would guess is your '4 wire' set up.

Off the top of my head, 1 wire or 3 wire alts now have an internal regulator and thus don't need that external bit (the 4th wire terminal).

There are far more knowlegable people out there than me who'll be able to help with what alternator to upgrade to but I though that diagram might help as a start!

Appreciate the Pic! Will have a look at it, would love to get a single or 3 wire alternator, but, not sure if I can hook it up

If you want to go with a single wire one that is easy you just tape up the other wires. All you technically need is the power wire hooked up. I still recommend putting in a seperate ground wire if you can with a high output alternator.

Personally I am not a huge fan of the single wire units. They require you to rev the engine to start to charge and it seems to me anyhow that they fail a little more often. You can go to the 3 wire no problem.

Great! Thanks!

If I was to go to the 3 wire set up, say 160 or 200 amp unit, which wires would I use? the 2 reds and the 1 large black? if so, do I just "tape up" the other smaller black wire?

Appreciate the help guys! At least now I can start "shopping" I have seen a few places on Ebay that sell marine alternators for a reasonable price

Thanks again!
Michael

Because I do not know what the exact color code is on your set up, I could only guess. I can tell you that the larger wire will go to the battery + output of the alternator. There should be a ground wire in there that you will use. The other wire will have power when the key is on only. That will go to the EXC or excite wire. The other wire you can tape off real good or shrink wrap it. Make sure it is wire tied away from anything it could ground out on.

The heavy gauge black wire is connected to the engine block.
The heavy gauge red wire is connected to the battery lug on your starter motor.
The small wires are used to control the regulator. One is direct to battey positive, the other to ignition switched positive.
Very easy to check which is which.

If you choose a self excited (one wire) alternator, mount the heavy black wire to one of the alternator mount bolts and seal off the two small wires.


Understand that if you choose a 150 to 200 amp capable unit and there is any issue like a dead battery or short to ground in the output wire, you will have a serious melt down problem.

The main posative wire will actually melt somewhere around 150 amps. If you go that route, I suggest a complete now 0 gauge wire from the alternator output direct to the starter lug and a fues link between the starter lug and the battery to protect the boat and the wiring harnesses.

http://www.dbelectrical.com/


I've ran one of these over 4 years no problems. The guys are great and cheap!

X2 on these! I also bought their mini high torque starters and 105 amp alts

I have been told to run at LEAST a #4 wire for the main charge wire, I am also going to use a battery "isolator" from Cole Hersee that will direct the charge where it needs to go [or so I am told]

If I run a 0 gauge main charge wire, would the ground wire also have to be 0 gauge as well?

Thanks for the help guys, I am much more confident about buying parts now, and I have already checked out the "DB Electrical" site [they sell a PILE of marine stuff] I might change the starter while I am at it.

Thanks!
Michael