Amp gage reading -20.

[Back N Black]

Amp gage is reading -20, but charging fine at 14.5 volts, runs fine starts fine. Is the Amp gauge the issue? I did the headlight up grade and ran a 10 gauge wire from the starter relay to alternator years ago. The battery is good, even tried another fully charged battery. When i turn on the headlights it goes down even more but voltage is still at 13.5 to 14 volts.

[John_Kunkel]

When you ran a large wire from the alternator to the starter you shunted the ammeter and it will only show discharge, not charge.

[Back N Black]

Ok, thank you.

[Nacho-RT74]

Eeeeehm... actually running that wire virtually bypasses the ammeter so the ammeter shouldn't be able to read any kind of load registry. Or not significant at least. IMHO there is something weird there

[John_Kunkel]

As long as the ammeter is in an active parallel circuit, there will be some current flow through it. My experience with running a wire direct from the alternator to the battery is the same as the OP's.

[metallicareload99]

It sounds like most of the electricity is coming in through the 10 gauge wire? Might check and clean all the connections from the big cable on the alternator to the ammeter?

[Nacho-RT74]

As long as the ammeter is in an active parallel circuit, there will be some current flow through it. My experience with running a wire direct from the alternator to the battery is the same as the OP's.

 Yes, but not able to read up to 20 amps

[John_Kunkel]

As long as the ammeter is in an active parallel circuit, there will be some current flow through it. My experience with running a wire direct from the alternator to the battery is the same as the OP's.

 Yes, but not able to read up to 20 amps

Disagree.

[Nacho-RT74]

 

I guess also will depend on quality of the new path, conections etc... but if the new path gets a lower resistance than the stock, I can't see a reason why the amm would be able to read any or at least THAT ammount of load.

 

[Back N Black]

John was correct, I disconnected the wire to the alternator and the Amp gage is reading normal again.

[Nacho-RT74]

Still doesn't make sense. Something is wrong elsewhere

[Back N Black]

Still doesn't make sense. Something is wrong elsewhere

You are correct, I have a problem. I was driving last night with low beam headlights on and all of a sudden the low beam lights got real bright and the bulbs blew. I'm using H4 lights with the relay upgrade that was posted on this site. I  had no power at the alternator positive, started the car and power was back again. Is it the alternator? Does the alternator get power from the amp gage? Should I hook up the wire again from the relay to the alternator?

[Nacho-RT74]

Check at black 12 gauge wire at bulkhead for something like this




While with the jumper wire between alt stud and batt you are "bypassing" the ammeter, the power to feed everything on car (main splice) is still between ammeter  alt side and bulkhead. So ANY load will be read by the amm as a discharge because there is no load coming from alt side up to the main splice (with or without jumper wire)

True the relay load won't be read BUT the rest of loads the car demands will be still read as a discharge because the factory setup distribution for load is on alt side and there is no way to change that except redesigning/redistributing the wiring on harness.

The jumper wire tipically made between alt and batt (which virtually bypasses the ammeter) will work as far the bulkhead conections are on "decent" conditions. If the damage already exists when this jumper job is made, there is not anything to save anymore and the CORRECT fix must be made, with or without jumper wire being added.

Read the stickied thread about how to understand the reading ammeter and how the load flows accordingly to the reading.

[Nacho-RT74]

Now we can see HOW THE AMMETER READING is tipically more powerfull than a Voltimeter. The ammeter was warning you there was something wrong around while the voltmeter didn't, but if we don't understand the gauge, won't detect the fail. Then "False fixings" float up

[Back N Black]

I checked the bulkhead connections, no signs of overeating. The car has all new factory wiring when I restored the car 18 thousand miles ago. Why would it burn out the headlights and not burn the fuse? I have 30 amp fuses, is that too high. Everything seems to be back to normal, but haven't replace the bulbs yet.

[Nacho-RT74]

 

Thinking...
My next guess could be a regulator... or alt failure. Able to provide volts and not amperes. Once got a weird fail with up to 20 volts or even more when increasing RPMs and no load. It was an internal pulsating short between one of the stator winding leads reaching one of the diodes and rotor vent vanes while spinining.

Just sharing my experience.

But I can't find any reason why you won't get power at alt stud if the line is not broken or loosen somewhere and the only point this could happen is at the bulkhead. Still with a reg or alt failure, the power at alt stud must be present since is coming from batt.

Even more with the jumper wire added so it should never loose power there, still with a bulkhead failure.