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Jay Young · 03-28-2022, 08:39 AM

Please help! Replaced alternator but still not charging. I have battery voltage on the "sensing" wire (thin wire) but zero on the Bat bolt when the key is in the on position. I do not know where this heavier gauged wire goes to so I can't check for continuity. The positive lead off of the battery goes to a cylindrical device that has several heavy gauged wires. I think one is to the starter and the other to the fuse panel but I can't see its termination. I can't find the isolator which the one wire alternators are supposed to be connected to to isolate the house batteries from the chassis batteries. I did find a cylindrical device in the house battery compartment that had two 5 amp fuses and I replaced them but I still don't know where the bat wire from the alternator goes to. I can't find schematics or help on line without paying for them and then I don't know if they would be the correct ones for my vehicle. I'm stranded and I need to get this vehicle to Litchfield, IL by April 1st. Thank you.

Injuneer · 03-28-2022, 09:44 AM

The big "BAT" bolt goes, oddly enough, to the battery, via a large diameter cable. If there is a diode isolator, it would instead go to that isolator. The isolator will likely be a large-ish (3-5") block which is made mostly of an aluminum heatsink... something like this: https://www.elecdirect.com/cole-hers...140-amp-3-stud. In turn, the isolator would hook to both the house and the chassis battery banks so that both get charged from the alternator.

Jay Young · 03-28-2022, 07:03 PM

I wanted to show you a picture of the battery isolator that was mounted directly above the alternator. It was cylindrical and had 4 screw posts, 2 large and 2 small in between. This has been replaced. The issue is that the red wire attached to the Bat Bolt does not go to the isolator. It is in a loom with the small wire from the alternator routed towards what appears to be the fuse panel. I have verified continuity of the ground from negative battery wire to the outside of the alternator. I can not verify continuity of that red BAT wire and therefore I don't believe any output of the alternator would get back to the battery. Do you know if a bypass wire could be run from the BAT bolt directly to the positive + post of the battery? Will this allow the vehicle to be driven to the repair shop without dying enroute?

Soppy · 03-29-2022, 06:24 AM

You can connect the large bolt on the alternator (+) directly to the positive pole on the chassis battery. It does not have to be disconnected when the engine is off.
It is possible that the fusible link has opened and is preventing the alternator from charging. Normally they are located on the battery side of the starter solenoid.

David 70 · 03-29-2022, 06:52 AM

The BAT wire most likely goes to the BAT wire on the starter solenoid.

Injuneer · 03-29-2022, 08:59 AM

Quote:

Originally Posted by Jay Young

Do you know if a bypass wire could be run from the BAT bolt directly to the positive + post of the battery? Will this allow the vehicle to be driven to the repair shop without dying enroute?

Yes.
Make sure you use a large conductor capable of handling the full current which the alternator can produce.

Jay Young · 04-02-2022, 11:02 AM

Well the positive battery wire had poor continuity so we replaced that and it was the first that we had seen a plus 13 or more volts on the Bat bolt @ the alternator and at the battery. We thought the IOU’s was resolved. But we got 17 miles down the road and gauge went below 10 volts and we had to pull over. It would not start this morning even though it was connected by booster cables. What is going on? We can’t keep on going 60 miles then charging it up again to move another 60 miles. Can anybody please help?

Jay Young · 04-03-2022, 12:20 PM

So we have only gone about 300 miles in about 4 days. We have used the Jeep to charge the battery back up to the point of burning up the Jeep’s alternator. The violtage drops down, hit a bump, goes back up. I need to know where the alternator bat Ted wires goes. We can’t go on doing this!