Alternator connected to starter WTH

[transmitterdan]

No it does not involve adding a relay. You have a wire where it should not be.

I am worried for the safety of your boat. Wiring of the always on battery circuit is very dangerous because there are usually no fuses. If you wire it wrong a big fire can erupt.

Please don’t misunderstand. I am trying to get you to see that there is something you don’t understand if you don’t know why the oil pressure light is always on.

[Charlie]

Trans I did not touch the ignition circuit wiring. When I read the wiring diagram I see that there is a fused positive wire that connects to the alternator. My theory is that this wire is back feeding the ignition circuit. I am going to test my theory by removing the fuse that is between the wire that I think is back feeding the ignition circuit and the ignition panel itself.

If the removal of the fuse stops the oil light/alarm then I am thinking of adding a NO relay that will only allow current through when the ignition is in the on position.

[transmitterdan]

Originally Posted by Charlie

Trans I did not touch the ignition circuit wiring. When I read the wiring diagram I see that there is a fused positive wire that connects to the alternator. My theory is that this wire is back feeding the ignition circuit. I am going to test my theory by removing the fuse that is between the wire that I think is back feeding the ignition circuit and the ignition panel itself.

If the removal of the fuse stops the oil light/alarm then I am thinking of adding a NO relay that will only allow current through when the ignition is in the on position.

Charlie,

This is my last post. If your oil pressure light is on with the key removed from the ignition something is wired wrong. The key switch turns this circuit on and off possibly via a pilot relay. It does not need another relay.

[wsmurdoch]

I find that having a copy of a wiring diagram that I can mark up is quite useful. A yellow highlighter marking the suspected route of the electricity from battery + to battery - backed up with a few voltmeter checks on the system along that route frequently unravels a problem.

Bill

[CaptTom]

Charlie, you need to not just connect the wire "to the alternator." You need to connect it to the CORRECT lug on the alternator. This IS a safety issue. Please re-read and understand the wiring diagram. It took me a while to really understand what was going on when I first delved into this.

This thread caught my eye because I just burned up a couple of wires, and singed a few more, because my alternator was NOT connected as you describe in the OP. For some reason, the alternator output was sent up into the wiring harness on a 10 gauge wire, only to tap into another wire and return back to the starter "hot" lug where the heavy-gauge battery cable connects.

It now has a temporary direct-to-starter connection. I've got a professionally-made 6-gauge cable on order. Sure, my crimps are OK, but safety and reliability are so critical here that I'm willing to pay extra for the peace of mind.

[Charlie]

Originally Posted by wsmurdoch

I find that having a copy of a wiring diagram that I can mark up is quite useful. A yellow highlighter marking the suspected route of the electricity from battery + to battery - backed up with a few voltmeter checks on the system along that route frequently unravels a problem.

Bill

Thanks Bill:

That was very helpful. I took colored pencils and traced the wiring diagram (I learned that in high school shop but forgot about it). I have attached it her. I am going to see if there is continuity between points A & B. If there is continuity that would confirm my theory that the alarm panel is being back fed from the always hot cable.