100 amp Powermaster

[teach]

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Want to make sure I don’t burn anything down here: I’m getting a 100 amp alternator (Powermaster, self-exciting) to replace my ac delco 63 amp. Currently, the bat wire goes from the back of the alternator to the starter (8-10 gauge I think… maaaaaybe 12?). I also have a fusible link at the starter and another at the firewall junction block. 4 gauge wire from positive battery to starter, 4g from negative battery to alternator bracket with a like 12 gauge wire that goes over to the interior body panel.

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My question is about what I need to rewire. What wires are sufficient, what are too small? Only running single electric fan, halogen bulbs, and moderate radio/amplifier setup. Mechanical fuel pump, HEI, etc, so no other big loads. I’ve seen so many different options/explanations.

Here’s what I THINK I need to do:
Upgrade alternator battery wire to 4 gauge out the back —> 200/175/150amp fuse —> starter battery post. Do I need to replace the fusible links, too? Or is this plan sufficient? Thanks in advance!

 

[Snoots]

I wouldn't replace the fusible links; unless, you're using NEW ones of the same rating.
I used welding cable for my ground and battery to starter. It has a greater current carrying capacity, better flexibility and can stand the heat. I coated the area where the insulation was cut with high temp RTV and used heat shrink. I also used a Harbor Freight crimper that worked great.

 

[75gmck25]

I replaced the charge wire for my 63 amp alternator when I switched to a 94 amp 12si, and I used the charge wire from a GMT400 from pick and pull. I would have to check the size (I think it may be 8 gauge) and it already had a fusible link. I ran the new wire directly over from battery positive to the BAT terminal on the alternator, so simpler routing. I also left the original charge wire in place and connected to the starter.

 

[Ricko1966]

I would not use a self exciting alternator. A factory GM alternator uses a sensing wire,far from the alternator so as to get a true system voltage reading so as to know current demands. A self exciting alternator reads voltage at the alternator where the voltage is really good,so it senses no need to up the current. A billion watt alternator producing random voltage is not better than a smaller alternator,keeping up with system demands.IMHO opinion you'd be better off with a larger factory alternator and keep the current sensing.

 

[teach]

I think that’s fair. I’ve already ordered this alternator, but if I have any issues with it, I may go this route. I feel like I need to commit at this point…. I know that’s not very scientific, but it does give me a data point I can use to improve my own understand. I always have had to learn the hard way…

 

[75gmck25]

I bought the 94 amp 12si to replace my 63 amp 10si because it was a direct bolt-in, and I added a bigger gauge charge wire just in case. It’s a simple upgrade, with no change of brackets, and the voltage regulator works just like the original.