Electrical Issues

Shawn Erwin · #1 (**permalink**) 10-30-2020, 03:24 PM

Greetings Everyone...need some help.

I recently took sometime to try to find out why I am having charging issues with my CR, which is volts falling below 12V with headlights, fans, and the fuel pump on. I tested the battery and its good to go. I had the alternator tested and its 105 amp with an output of 14.7. In discussions with the guy at the alternator shop I found out the charging wire coming off of the alternator is way too small like 12 gauge too small (previous owner issue

). I'm in the process of tracing the wire and it is doesn't look like it is going to the battery.

SO, my questions are...what is the normal gauge wire for the output wire for the alternator? (6 gauge?)...Should the charging wire go direct to the battery or can it be wired to the starter relay which has a positive connection directly from the battery. I am leaning toward direct wire to the battery.

Thanks,
Shawn

twobjshelbys · #2 (**permalink**) 10-30-2020, 05:26 PM

Check your grounds.

patrickt · #3 (**permalink**) 10-30-2020, 05:48 PM

Quote:

Originally Posted by Shawn Erwin

SO, my questions are...

Shawn, before you go to heroic measures on tracing wires or replacing them, try a quick temporary patch wire from your alternator directly to the connection on your starter solenoid that has the fat red wire running to the positive side of the battery. Just disconnect the charging wire from the alternator (that you think is too small) and tape it off safely. Then run a nice short 10 gauge wire directly from the alternator to the starter solenoid. It doesn't have to be pretty, just a quick wire between the alternator and the solenoid that has nice terminals that connect well. Now, your ammeter will not be reading properly, so ignore it. But you should have a healthy 13.5 to 14.5 volts throughout the system with all your stuff on and your engine revving over 1200 RPM. Do this first as a test.

Shawn Erwin · #4 (**permalink**) 11-10-2020, 08:57 AM

OK..check all grounds and they are good, Changed the alternator to eight gauge and ran it directly to the starter relay, and rewired all of the wires going to the cooling fans. With the fans, fuel pump, and the headlights, etc. running I'm at 13.5 to 13.7 volts at 1500 RPM...thoughts? I think the fans are pulling a lot of juice.

patrickt · #5 (**permalink**) 11-10-2020, 09:07 AM

Quote:

Originally Posted by Shawn Erwin

With the fans, fuel pump, and the headlights, etc. running I'm at 13.5 to 13.7 volts at 1500 RPM...thoughts? I think the fans are pulling a lot of juice.

13.5 to 13.7 is fine. Now, if you want to know how much each component is pulling in amps, just buy an inductive ammeter. You clamp it around the 12v+ wire going to the load and it will tell you the true amperage for that circuit. For the fans, that will be particularly telling because you will need to do it under different heat conditions to see what the varying amperage readings are based on under-hood temps. Then compare it to the manufacturer's chart to see if you're reasonably close to their specs.