6V battery with a 12V generator? |
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can_o_worms
Member Joined: 20 Oct. 2018 Location: Portland, OR Status: Offline Points: 5 |
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Posted: 20 Oct. 2018 at 5:44am |
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I typically like to figure things out for myself, but I'm currently stumped...
I recently took possession of my Grandfather's '49 CJ3a, and have been tinkering and getting it rolling. It seems to be pretty solid from a mechanical standpoint, but I've run into something vexing. The generator didn't seem to be charging, so I went through the testing steps outlined here: http://www.cj3a.info/tech/charging.html From those tests, it looks like I have a type A generator, the tag says GDZ-4817-A, which should be a 6v generator. The coil is a 6v coil, and the voltage regulator is labeled for 6v also. However, when I run the full field test on the generator, at idle (low idle, no throttle) the outuput of the generator was 12.5v, when I brought the idle up it increased and peaked somewhere around 30v. Now, I'm new to old Jeeps... and generators... and 6 volt systems... but something doesn't seem right here, and the battery isn't charging when it's Did someone have the 6V generator rewound for 12v, but forget to change the rest of the electrical components over? Or do I just have a bad regulator? Any insight would be greatly appreciated. |
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I have no clue what I'm doing... (don't tell my wife!!!)
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Bob W
Member Sponsor Member x 4 Joined: 08 Aug. 2005 Location: Monticello, NY Status: Offline Points: 1691 |
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It may be a bad voltage regulator. Sounds like the current limiting section of the regulator is not working. The output of the generator is not making it to the battery. If it were the current would go up and the voltage would go down to a reasonable number.
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Lee MN
Member Joined: 13 Aug. 2008 Location: Harris, MN Status: Offline Points: 4949 |
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X2, a 6V generator will charge 12v easily full fielded! Lee |
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LEE
44 GPW-The Perfected Willys 49 2A “If you wait, you only get older” 67 M715 American Made Rolling History |
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WeeWilly
Member Sponsor Member x 2 Joined: 07 May 2009 Location: Clayton IN Status: Offline Points: 3423 |
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My generator only had around 7 volts when bench tested at idle speeds. Your readings are normal for a 12 volt generator so maybe it was converted to a 12 volt. Jim
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47 CJ2A (Ranch Hand) 48 CJ2A, 48 Willys truck, T3C 3782, M274 (Military Mule)
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Lee MN
Member Joined: 13 Aug. 2008 Location: Harris, MN Status: Offline Points: 4949 |
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Not so with a 6V labeled regulator! Lee |
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LEE
44 GPW-The Perfected Willys 49 2A “If you wait, you only get older” 67 M715 American Made Rolling History |
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Unkamonkey
Member Joined: 23 Mar. 2016 Location: Greeley CO Status: Offline Points: 2093 |
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You have a wireing issue or a regulator problem. Them old things Just did not put out that much power.
Edited by Unkamonkey - 20 Oct. 2018 at 9:50pm |
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uncamonkey
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WeeWilly
Member Sponsor Member x 2 Joined: 07 May 2009 Location: Clayton IN Status: Offline Points: 3423 |
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I was just testing the gen. didn't have a regulator hooked up to it, just grounded the field. Jim
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47 CJ2A (Ranch Hand) 48 CJ2A, 48 Willys truck, T3C 3782, M274 (Military Mule)
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Bob W
Member Sponsor Member x 4 Joined: 08 Aug. 2005 Location: Monticello, NY Status: Offline Points: 1691 |
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With the field grounded and nothing connected to the armature terminal those original readings are normal for a 6 volt generator.
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WeeWilly
Member Sponsor Member x 2 Joined: 07 May 2009 Location: Clayton IN Status: Offline Points: 3423 |
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Correct, I was pointing out to the original post that his sounded high for for a 6 volt generator with a full field test being 12,5 volt at idle speed. Jim
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47 CJ2A (Ranch Hand) 48 CJ2A, 48 Willys truck, T3C 3782, M274 (Military Mule)
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Ol' Unreliable
Member Joined: 25 Sep. 2016 Location: CO Springs CO Status: Offline Points: 4226 |
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Welcome to the page, can_o_worms!
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There's a reason it's called Ol' Unreliable
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Lee MN
Member Joined: 13 Aug. 2008 Location: Harris, MN Status: Offline Points: 4949 |
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Obviously we are all wrong then Lee |
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LEE
44 GPW-The Perfected Willys 49 2A “If you wait, you only get older” 67 M715 American Made Rolling History |
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can_o_worms
Member Joined: 20 Oct. 2018 Location: Portland, OR Status: Offline Points: 5 |
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Thanks for the input everyone! It looks like it is a 6v generator and the voltage regulator was not functioning properly.
After tinkering more today and watching this incredibly informative video about voltage regulators (https://youtu.be/zRk1xbJIBcY) I decided to pull the regulator apart and see if I could determine the problem. The VR looked really clean inside, nothing burned or obviously faulty. I did notice that the components inside were all adjustable. I cleaned all of the contact points and set the clearances as outlined in the video. I reinstalled the VR and fired her up. Still not charging properly, but I was getting 1.75v at the armature terminal of the generator, where I was getting 0 volts before. I cracked open the regulator again and increased tension on the voltage regulator coil spring, and reduced the tension on the circuit breaker spring. I put it back together, fired it up, and am now showing 7.5v at the armature terminal on the generator! Measuring voltage across the battery terminals is only 6.5v, which is an increase from the 6.1v I was getting before. I'm guessing that I'll need to go through the wiring and clean all of the connections under the dash to really get it dialed in. But it's progress. Out of curiosity, does anyone have the correct clearances for the contact pointd and air gap on these voltage regulators? I know I closer than I was, but I'd rather start with solid specs and adjust from there...
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I have no clue what I'm doing... (don't tell my wife!!!)
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Lee MN
Member Joined: 13 Aug. 2008 Location: Harris, MN Status: Offline Points: 4949 |
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I would run it till the battery is fully charged!, 6.5 volts on a battery is probably correct on a non running engine. 7.5V on a running engine is most likely perfect!...
Lee |
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LEE
44 GPW-The Perfected Willys 49 2A “If you wait, you only get older” 67 M715 American Made Rolling History |
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Rus Curtis
Member Joined: 25 Mar. 2010 Location: Alabama Status: Offline Points: 1733 |
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I'm no expert but I believe that what you did is the procedure vs. a "set gap" like you would have on a distributor. You set the tension to whatever is needed to get the numbers. Nice work!
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Rus Curtis
Alabama 1954 CJ3B Bantam T3-C |
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can_o_worms
Member Joined: 20 Oct. 2018 Location: Portland, OR Status: Offline Points: 5 |
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Well, from what I can tell, it looks like adjusting the tension is the final step in setting up the generator regulator. I came across a document, that is attached to this post that gives all of the information necessary to correctly service an Auto-lite regulator for 1935-1962 Willys. The air gap specifications are somewhat different than what is given in the video I mentioned above. While the unit in my 3A doesn't look like an original Auto-lite, it is nearly identical with the exception of the resistors on the bottom of the unit. They are of a different type, and do not appear to be replaceable, and hopefully will work with the same specifications. In any case, I think I'm at least on my way to getting set up properly, and I hope that the resources I've found and shared can help demystify these charging systems for others. |
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I have no clue what I'm doing... (don't tell my wife!!!)
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