Battery overcharging 15.3-15.6V

[HALIFAXHOPS]

Change it.
Watch this

 

[JG1966]

Change it.
Watch this

I did watch that yesterday. I figured because mine wasn't one of the adjustable types, the ohms might be different because it passed every other test I tried. That said, I'm going to get a new one and I'm bringing my multimeter with me.

 

[HALIFAXHOPS]

Thats just where he set it I toss them if it is over 2k

 

[72RoadrunnerGTX]

Thanks 72, my head is spinning from looking at these wiring diagrams. I have two questions.
1. You said to "inspect the bulkhead terminals in the charge circuit." What is the charge circuit (what color wires)? Is that the wire from the battery/starter relay with the fusible link?
2. Are any of the wires/connections that could be giving me issues going through the fuse box or only the bulkhead connector/molex connectors?
Thank you again for all your help.

By far, the weakest link in the factory charging wiring, many years down the road now, is the use of Packard connectors in the bulkhead connector for the higher current load charge circuit. The black 12 ga wire from the alternator output and the red 12 ga wire running to the battery via the fusible link.

The high voltage drop you are seeing is result of the total resistance of all the conductors and connectors between the regulator ign1 terminal and the battery while in operation. This includes, the blue wiring in the engine harness to the bulkhead connector terminal, a blue/white trace wire to the ignition switch Molex connectors, the ignition switch itself, the ign switch red wire and the its Molex terminal, 12 ga red wire run to splice 1, 12 ga black wire from splice 1 to the ammeter, the ammeter, red wire from ammeter to bulkhead terminal, red 12 ga wire in the forward lighting harness to the fusible link disconnect, the fusible link to starter relay battery terminal, then the short 10 ga run from the starter relay to the battery post. Fuse box is not in play with this issue.

Of all these possibilities, the Molex terminals, and bulkhead terminals have been the most common problem over time. Even if not currently showing heat damage, resistance builds. There are many other current threads here discussing this issue, and ways to correct.

 

[72RoadrunnerGTX]

Ok. This might be a clue. When I test for voltage drop from battery positive to blue wire at alternator with key on, I get 1.32V volts. If I unplug the voltage regulator, it drops to .72V. Does that narrow anything down?

Voltage drop diagnostics require a somewhat normal current flow to be taking place at the time, removing any load will lower the voltage drop reading. Unplugging the regulator is just lowing the current flowing, the lower voltage drop reading is expected.

The MAD reply was a joke, If you have seen any of the ammeter threads here lately, you will see I’m not a big fan of the blanket application of the MAD Electrical modification to an otherwise healthy factory charging system and any other vehicle applications other than the late seventies (plastic ammeter) trucks that the article specifically addresses.

 

[JG1966]

By far, the weakest link in the factory charging wiring, many years down the road now, is the use of Packard connectors in the bulkhead connector for the higher current load charge circuit. The black 12 ga wire from the alternator output and the red 12 ga wire running to the battery via the fusible link.

The high voltage drop you are seeing is result of the total resistance of all the conductors and connectors between the regulator ign1 terminal and the battery while in operation. This includes, the blue wiring in the engine harness to the bulkhead connector terminal, a blue/white trace wire to the ignition switch Molex connectors, the ignition switch itself, the ign switch red wire and the its Molex terminal, 12 ga red wire run to splice 1, 12 ga black wire from splice 1 to the ammeter, the ammeter, red wire from ammeter to bulkhead terminal, red 12 ga wire in the forward lighting harness to the fusible link disconnect, the fusible link to starter relay battery terminal, then the short 10 ga run from the starter relay to the battery post. Fuse box is not in play with this issue.

Of all these possibilities, the Molex terminals, and bulkhead terminals have been the most common problem over time. Even if not currently showing heat damage, resistance builds. There are many other current threads here discussing this issue, and ways to correct.

Thanks 72. This right here might be something....."red wire from ammeter to bulkhead termin, red 12 ga wire in the forward lighting harness to the fusible link disconnect".....When I was looking at bulkhead connectors that one had a slight issue (bulkhead No. 15 spot). I didn't fix it yet, but is that bulkhead connection --- the red wire that runs to the headlights -- part of this circuit?

 

[72RoadrunnerGTX]

Thanks 72. This right here might be something....."red wire from ammeter to bulkhead termin, red 12 ga wire in the forward lighting harness to the fusible link disconnect".....When I was looking at bulkhead connectors that one had a slight issue (bulkhead No. 15 spot). I didn't fix it yet, but is that bulkhead connection --- the red wire that runs to the headlights -- part of this circuit?

There are two red wires in the forward lighting harness, a 16 ga red wire (high beams, not involved here) at bulkhead terminal 14, the battery charge run is a 12 ga (larger red wire) at terminal 16. Do your voltage drop testing at these various locations while in operation to pin point issue. My recommendation is to by-pass the bulkhead connections altogether on these circuits. And replace teh high current Molex connectors with something that can handle the current, see this other current thread

 

[JG1966]

There are two red wires in the forward lighting harness, a 16 ga red wire (high beams, not involved here) at bulkhead terminal 14, the battery charge run is a 12 ga (larger red wire) at terminal 16. Do your voltage drop testing at these various locations while in operation to pin point issue. My recommendation is to by-pass the bulkhead connections altogether on these circuits. And replace teh high current Molex connectors with something that can handle the current, see this other current thread

Well, I found an issue with the red high beam bulkhead connection (terminal 14). I will fix that either way. But clearly that won't fix my problem. My big red wire already goes through a drilled hole in the bulkhead (terminal 16), so there's no place to check voltage drop there except maybe where I've connected it to the black amp wire (part of the MAD bypass). I bought a new voltage regulator but that wasn't it. On the bright side, I've got voltage drop down from 1.40v to 1.20v just from cleaning some bulkhead and Molex connecters.

 

[JG1966]

There are two red wires in the forward lighting harness, a 16 ga red wire (high beams, not involved here) at bulkhead terminal 14, the battery charge run is a 12 ga (larger red wire) at terminal 16. Do your voltage drop testing at these various locations while in operation to pin point issue. My recommendation is to by-pass the bulkhead connections altogether on these circuits. And replace th high current Molex connectors with something that can handle the current, see this other current thread

Sorry I've been away. I'm making some progress. I've cleaned/improved a bunch of connections along ignition 1 and charge circuit. I've gotten voltage drop from battery positive to blue wire at alternator to .80V, down from 1.40V. Getting better but still high. Alternator big battery post is putting out 15.1v and battery is charging at 15.3V at idle and 1500 rpm. Does this narrow anything down? Maybe wire from alternator to starter relay post?

 

[JG1966]

There are two red wires in the forward lighting harness, a 16 ga red wire (high beams, not involved here) at bulkhead terminal 14, the battery charge run is a 12 ga (larger red wire) at terminal 16. Do your voltage drop testing at these various locations while in operation to pin point issue. My recommendation is to by-pass the bulkhead connections altogether on these circuits. And replace teh high current Molex connectors with something that can handle the current, see this other current thread

72GTX, I wanted to give an update since you helped me so much. I cleaned some more connections and cleaned, redid and tightened up some stuff (mainly the red/black ammeter wires I have connected under the dash). I also realized every time I was checking my voltage at the battery that my electric vacuum pump was running. So I removed fuse and checked and I was down to 14.9. I am down to .65V voltage drop from battery positive to blue alternator wire. Not ideal, but definitely much better than 15.6v charging and 1.4V voltage drop. The only thing I haven't checked/cleaned yet is ignition switch connections. That's next. But thanks again. I'm getting there.