Quote:
Originally Posted by Rick Bollinger
This is great! On my 68 the PO changed to a one wire alternator but just added a spliced in wire to the harness. Well it charges ok but the original alternator harness was just shoved up by the voltage regulator. Nothing taped or deleted just bare wires and connector. Now I know what I need to do to clean up the mess and to delete the voltage regulator. Will wiring in the brown wire to the alt make my stock amp gauge work?
Thanks for the great thread
Rick
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There are so many guys who install a one wire alternator and then just run the output wire directly to the battery positive. It's just dumb to do that because the alternator is the main power source for the electronics in the truck. A lot of them think the battery provides all the power and the alternator is just there to recharge the battery. While this works on hot rods and tractors, it just doesn't supply all the juice for cooling fans and AC systems and any other high load items.
If you check the diagram in post 5, it shows the correct way to wire the alternator output so that the battery gauge will work and the battery will charge. Notice the small 12 gauge wire from the battery to the main junction.
This is the charging wire for the battery and it also supplies emergency voltage when the alternator fails and when the engine is off.
The alternator output wire runs to the main junction so that it can supply voltage and current to all the systems in the truck. if it's run straight to the battery then all the output from the alternator goes through this small 12 gauge wire from the battery to the main junction. It's too much load for that small wire to carry especially if other loads are added.
The other problem with running the output wire directly to the battery positive is that it defeats the purpose of the battery gauge to measure the output voltage of the alternator and the state of charge of the battery.
Again looking at the diagram, notice the two small wires with fuses. One is connected to the battery at the fender junction and the other is is connected to the main junction with the alternator output wire. They are connected on each end of the smaller 12 gauge battery charge wire. This is so they can sense the voltage on the alternator and the battery and compare the two.
These two wires are both positive and they run directly to the cluster plug in the dash and then directly to the battery gauge.
If you run the alternator output wire to the battery positive they will be right together and the battery gauge cannot tell if the alternator or the battery is working correctly.This is rather simplified but it explains the need to keep the alternator output wire and the battery wire apart. I hope it helps.
The brown wire is just used to excite the alternator and to light the charging light if the charging system fails. if you have a battery gauge then you won't have a charging light anyway. If it's a one wire then the brown wire is not used but the battery gauge will still work if the alternator output wire is wired correctly. the fuses must be good and the wiring must be making contact all the way to the gauge in order for the gauge to work.