snowman1510 Posted January 12 Share Posted January 12 Good Morning, I just put on a new generator and battery on my 55 Buick Super. I polarized the generator when installed. However, leaving the battery hooked up ran it down so I got it recharged and put back on (I leave it disconnected now). I started the vehicle and tested the battery with one of those harbor freight tools that you connect to check battery health and if it is charging. Well the battery was charging with the new generator, but not enough to be 14 volts. The amp Gage showed that the battery was charging. I stopped the motor disconnected the battery and tightened the generator belt. Started the vehicle again. The tool showed that the vehicle was overcharging. Looking at the amp Gage it showed the battery was discharging close to the D. Applying rpms made the gauge drop lower. What should I do to get the overcharge to stop and the amp Gage to get a good reading? Is there a potential issue with my voltage regulator? Do I need to depolarize since battery disconnection? Am I missing something entirely? I would appreciate any input in this matter. Thank you! Link to comment Share on other sites More sharing options...
Bloo Posted January 12 Share Posted January 12 (edited) Could the battery be in backwards? Colors don't mean anything. Follow the battery cables and see where they go. It is a negative ground car. Then polarize it one more time and see what you have. About the dead battery overnight thing, with everything shut off, disconnect a battery cable and connect an old fashioned incandescent test light between the now empty battery post and the cable you disconnected, so the test light is now in series. If there is an overnight draw, the light should glow brightly. Then to see if it is the charging system's fault, disconnect the GEN or ARM wire(s) at the regulator. Careful, that post might be battery hot if the cutout points are stuck. You won't get fireworks though as long as the test light is there. Worst case, it glows brighter. If disconnecting the GEN/ARM wire(s) makes the test light go out, take the cover off the regulator and unstick the cutout points. If disconnecting the ARM/GEN wires doesn't make the light go out, hook the wires back up and look elsewhere for the current draw. You'll probably need a wiring diagram. The traditional way to do this is pull fuses one at a time to make the light go out, and if you find one that does make it go out, follow the diagram to see what that fuse leads to. If not, look on the diagram for unfused things, and start disconnecting them one at a time until you find out what makes the light go out. The 3 most common causes back in the day were: 1) Borg clocks, 2) Glovebox light on with door shut, and 3) Brakelights stuck on and/or hydraulic brake light switch partly shorted, in that order. Edited January 12 by Bloo (see edit history) 4 Link to comment Share on other sites More sharing options...
snowman1510 Posted January 12 Author Share Posted January 12 I thought the vehicle was a positive ground? I'll try polarization again as well. I will try the other solutions for the overnight draw. 1 Link to comment Share on other sites More sharing options...
snowman1510 Posted January 12 Author Share Posted January 12 Isn't the system a positive ground? Link to comment Share on other sites More sharing options...
Bloo Posted January 12 Share Posted January 12 (edited) No. The only GM positive ground cars I have ever heard of are very old Cadillacs, and maybe some Oaklands(?). I don't recall when Cadillac abandoned positive ground, but it was long before the 1953 change to 12 volts. Buick, Chev, Pontiac, Olds etc. are all negative ground. Edited January 12 by Bloo (see edit history) 1 1 Link to comment Share on other sites More sharing options...
Grimy Posted January 12 Share Posted January 12 The last Cadillac positive ground was 1942. Buicks, from the late 1910s at least, have always been negative ground. 2 Link to comment Share on other sites More sharing options...
snowman1510 Posted January 12 Author Share Posted January 12 (edited) Oooooops. Sometimes I feel like the source of my own problems lol. I'll switch it around. Should I repolarize as well? I am surprised it fired and ran. I am also surprised the electrical systems worked. Is there a possibility I damaged any components? Edited January 12 by snowman1510 (see edit history) 1 1 Link to comment Share on other sites More sharing options...
Bloo Posted January 12 Share Posted January 12 (edited) Yes. Definitely polarize, and before you try to start it. There is a possibility of damage, but it depends on too many things I don't know about your car. Of course modern electronics always goes up in smoke when you do that, but old electromechanical car stuff was surprisingly tolerant. Sometimes people drove them around wrong for years. Sometimes the radio even worked. The ammeter goes backwards. Spark is weaker. Old voltage regulators had special plating on the points that was different for positive ground. Running backward would shorten the life, but they would usually work. I am amazed how often it was no big deal. Of course if there were one or two electrical devices that couldn't take it, they would refuse to work and maybe go up in smoke. Edited January 12 by Bloo (see edit history) 3 Link to comment Share on other sites More sharing options...
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