I would like to replace my 75A OEM three wire alternator on my 1986 Dodge D150 pickup slant six with a Powermaster 75191 95A one wire alternator. I have factory A/C, two thermostatically controlled radiator cooling fans, and high intensity headlights (connected to battery via relays.) The charge wire from the alternator to the 8 conductor connector keeps overheating and partially melting the OEM connector. I have two electric cooling fans (usually they are not running when the truck is moving at highway speeds unless the A/C is on or it is a very hot day) that probably are the culprits here. I intend to run a 6 ga marine quality wire with crimped copper lugs from the alternator directly to the battery (about six feet distance.) I would route the wire in front the radiator to the battery on the left inner fender.

This alternator has an internal regulator so I won't need the OEM external regulator (which regularly fails). I intend to remove the external regulator and cap the wires.

1. Do I need to install a fuse and/or fusible link between the alternator cable and the battery terminal? I understand a 10 ga fusible link is the proper size for a 6 ga wire.
2. Are there any other concerns with this modification with relationship to the OEM wiring?
3. How do I insulate and waterproof the fuse?
4. If I just use a 10 ga fusible link, how long should it be?
5. Should the fusible link be inline with the 6 ga cable or should it be connected directly to the battery terminal with the 6 ga wire behind it leading to the alternator?
6. Are butt connectors okay for the connections between the fusible link and the 6 ga cable?

One thing to consider is that most if not all 1 wire alts have a draw when the key is off due to the internal regulator. You need to either have a really heavy duty relay (at least 100A rated) for the alt charge/batt wire that is energized by your ign key switch, OR a master batt cutoff switch that you turn off if you are going to be away from the car for more than a day or so.

Best,

Lou

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Home of Slant6-powered fun machines since 1988

Thanks for the tip. I have a negative battery post quick switch disconnect that you simply turn the screw to disconnect the battery.

Why do you want a 1-wire alternator? They're not superior.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I need a higher output alternator and I don't think the old wiring in the truck can support more amperage.

There is no benefit to a 1-wire alternator in this case; a regular external-regulator alternator will do just fine. Run however heavy a cable you want from the alternator's output stud to the battery positive terminal, then you aren't putting heavy current through the section of old wiring it sounds like you're concerned about.

(the drawback of a 1-wire alternator is that when the regulator fails, you're hosed. You can't just swap on a new regulator in a couple of minutes and keep driving.)

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

That is a reasonable approach. Do I need a fuse or fusible link on the 6 ga wire from the alternator to the battery?

I like to build extra safety into the high-current path from the alternator to the battery by using dual 10ga wires with dual fuses in each wire, as described here.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.