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Old 09-26-2006, 05:49 AM
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Switch from 10si to 12si alternator

The original alternator on my '75 GMC pickup was a 63 amp 10si. I can switch to a newer 94 amp 12si with the same clocking, and its a direct bolt in. However, I also want to upsize the charge wire to 8 gauge with a 12 gauge fusible link.

When I run the new charge wire, should I use the original routing, which goes from the alternator down to the starter, or should I make a more direct connection to the batteery? Some of the newer trucks ('96-'99 vintage) use a charge wire directly from the bat terminal on the alternator to the battery, and do not route it down to the starter.


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Old 09-26-2006, 02:38 PM
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Doc here,

The main problem with running the output wire to the battery, is that is is then subject to a more possible failures then it would be at the starter..

You run the risk of corrosion, and corrosion traveling up the wire (until it becomes unusable) Where as a Battery cable is a bolt on replacement, you now must remove and replace the wire..within the harness..It also becomes more prone to "becoming loose" as the cables are removed, cleaned , or the vehicle is worked on..Butt Splice Stub~outs are a nightmare also..

PLUS you really don't want a fuse link that close to a gassing battery..

The Starter location is one that has proved well over the years..and I advocate it..At best if it must be relocated..do so to a single terminal binding post at or near the battery, and make all your junctions there.

You'll have a better system..

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