[MadMacks]

I’m upgrading the wiring (big 7) on my 1991 Laredo to allow for a larger amp alternator and generally improve electrical performance overall. I’m using 2 gauge wiring for all of the upgrade changes.

Question…the current OEM alternator output wire runs to the PDC which has two 50 amp fuses labeled Alt1 and Alt2. Rather than replacing this wire can I simply stack the new 2 gauge wire to the existing mount point on the alternator, run the new 2g wire to my new ANL fuse and holder, and run the fuse output wire directly to the battery positive terminal?

Rather than ripping the OEM wiring loom apart, and messing with the OEM PDC set up, can’t I just leave the current OEM wiring that runs to the PDC and the two 60 amp plugs as they currently are?

The stock alternator puts out around 90 amps but I’ll be replacing it shortly with a Powermaster 43311 alternator that puts out up to 170 amps. That will help after I install my new winch.


I don’t see why this wouldn’t work just fine, but I’d like input from others that have done similar upgrades.

 

[4.3L XJ]

Yes you can do that. I am not sure why they have those fuses in the PDC and then fuse everything else. I have a 250 amp alternator and do it that way. You have a potential of needing much more power to charge the battery or run something like a winch anyway.

 

[MadMacks]

That you for the confirmation…it seemed logical and even makes the wiring “larger” by using both fused bath ways.

 

[4.3L XJ]

Wait, let me clarify. Run your new 2 ga wire directly to the positive on the bat to starter. Then leave the rest alone

 

[MadMacks]

For clarity…the following all uses fine stranded 2 gauge wiring using copper connectors properly crimped and sealed.

New engine to firewall ground strap.
New battery + to starter cable.
New battery + to PDC cable.
New battery - to engine block cable.
New battery - to body cable.
New military grade battery post connectors.
New alternator to ANL fuse cable.
New ANL fuse to battery cable.

The current (no pun intended) factory alternator to PDC cable has a fuse link and looks like it wires up inside the wiring loom at the PDC to two fuses in the PDC (Alt1 & Alt2), each using a 60 amp fuse. I assume those two circuits then run off to the battery + and to other loads.

When I swap out the existing alternator (rated at 90 amps) with a HO alternator that “small” factory cable will not really properly handle the new HO alternator output. So the standard thing to do, as I understand it, is to replace the factory wire with the larger 2 gauge wire. But…that still pushes the power from the alternator thru the PDC and the small blade fuses, and requires jacking around with the wiring in the PDC.

Rather than doing that I would prefer to leave the factory wiring installed in the PDC and still attached to the alternator. I’d then add the new 2 gauge wire to the same + alternator post, route it to the new ANL fuse (175 amp) and then on to the battery + post.

This set up provides two + paths, from the alternator to the PDC and directly to the battery, and would let the higher amp currents flow to both the PDC existing set up and to the battery thru the ANL fuse. I see no reason why this shouldn’t work, and allow the battery, and other batter connected loads like a winch to get the max amps available when needed.

Effectively, the new battery + to starter and new alternator + to battery + is exactly like “Run your new 2 ga wire directly to the positive on the bat to starter. Then leave the rest alone.” They are both directly connected to the new military grade battery terminal connector.

 

[MadMacks]

Update. I just pulled the factory cable off the alternator and am using it to power a separate power bar for accessories. Makes it simpler to hook up things like small lights, etc.