91 BF 100 amp alternator upgrade question

[shag]

Ok, I am having trouble getting this theory through my head. I've had a little advice and I just need clear instructions on how to hook this up. 91 Barefoot/Excel, 454 pro tec with low pressure electric fuel pump. Factory alt was 50 amp (or just under) with the 50 amp breaker. Factory alt was toast (I'm restoring a boat I just got) New 100 amp certified marine (97 amp actual output) alternator was only about $15 more (and was even chrome! It's all they had) and is a one wire. Also just had the starter rebuilt by a very reputable starter shop that I've used before.
Do I run a heavy gauge (4 or 6 ga) from the new alternator output to the hot terminal on the starter, then from there with heavy gauge to the positive battery terminal? essentially by passing the 50 amp breaker? If so, then what do I do (if anything) with the existing #23 and then #22 from the solenoid mounted at the back of the intake. Do I put both #22's on the same side of the solenoid?
Should I get a 100 amp breaker, and where to install inline?
I know the starter cable should be at least 4 ga due to the high amp draw for starting.

I will be installing a Perko switch (with batt 1, batt 2, both, and off detents) with 2 batteries, relocating the batteries to the port side for better weight distribution and a shorter battery-starter cable.

Sorry if the attached diagram is sideways.... :/

I also need to get a slightly longer belt as this particular alt. is just a bit bigger and contacts the block when installing the belt. A longer belt will still allow for alt movement for belt changes without any other clearance problems.

Thanks in advance!

[Mamigacz]

I've read that you only need a 8 GA wire for a 100 amp alternator. With that being said, I think 4 GA. wire would be total overkill. I can't read the number bubbles on that wiring diagram, the image is too grainy. A (1) wire alternator is self exciting. It doesn't need the 12volts from the ignition switch to excite it. This means that the wire that is tied to the ignition switch is no longer needed.

I would think you could keep the 50 amp breaker. However, the alternator could never put out its full capabilty without blowing the fuse. They basicly work on demand. If your system needs 30 amps, your 100 amp alternator will produce 30 amps. In your system needs 60 amps, the alternator will produce 60 amps and the fuse will blow. Bypassing the fuse could be a problem if there is ever a direct short. The wire could start on fire.

I think the correct way to wire it is to run the new 8 GA (or 6 GA wire) from the starter solenoid to the fuse. Then another 8 GA wire should be ran from the fuse to the alternator.

[shag]

93PCMprotec.pdf

Thanks for the input, and sorry for the grainy image. I just need to get a good solid explantion on this. I know people have done it, and I surely don't want to have any safety issues. I think I have attached the PCM manual and on page 57 is the diagram for the chevy protec wiring.

[TX-Foilhead]

I can't see that one either. The orange wire needs to meet the wire to on the starter relay that goes to the battery. Mine just has the single relay so yours will be different and I think it should go to the relay on the starter. Look under Wake Fun's profile for he PCM kit and the way they do it. If you keep the orange wire where it is the dash is unprotected by the breaker and the battery is on the wrong side of it. The way it is wired from the factory protects the wire to the dash from the battery because the alternator isn't big enough to smoke them.The 100 amp alt is big enough so the alternator output moves to the other side where the wires will be protected from the alternator and the battery.

[shag]

I think I understand. I will need to put one of the current wires on the relay on the same side....(hot side).... I will try to find wake fun's post

[TX-Foilhead]

In your case straight to the battery might be easiest, it's at least 2 more feet of wire for me and my battery has been moved to the port side. It's good to figure it out for yourself even though it can get frustrating. In the end you know exactly how your boat works and that can be priceless sometimes.