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6 to 12 volt conversion

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CAL View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CAL Quote  Post ReplyReply Direct Link To This Post Topic: 6 to 12 volt conversion
    Posted: 19 June 2018 at 8:33am
I have a 47 cj2a I did a frame off on with body mods I left it 6 volt but have been looking at changing it to 12 volt does this require a lot of changes such as gages lights and wiring?
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harvey45 View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote harvey45 Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2018 at 10:07am
I would ask why convert it?  Is it slow to spin over? I kept mine 6 volts and had starter and generator rebuilt.  Made sure I have a good frame ground and timed correctly and starts right up all 6 volt. Mine was a ground up restoration too. 

On the 12 volt conversion 
Battery and voltage regulator and 12 volt bulbs.  Your current 6 volt generator should keep it charged unless your going to run a radio. 



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67charger View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 67charger Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2018 at 10:48am
Its better to convert from 6 volt to 12 because at least you can go back to 6 volt easily "the gauge wire is correct".  I think you have to change the light bulbs, if you don't have an externally resisted coil you should add a ballast resistor to drop from 12 volt to 6 volt before the coil.  Your starter won't like 12 volts going to it along with your flywheel but you can use it that way.  If you have a windshield wiper motor it will need to be changed too.  I don't know if your fuel gauge would need a resistor before it? 


Edited by 67charger - 19 June 2018 at 10:51am
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tufcj2a View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tufcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2018 at 1:24pm
Full conversion you need to change:

 - Lights, all bulbs (don't forget courtesy light, high-beam light on dash in addition to headlight/taillight
 - Alternator (one-wire or not, internal regulator or not; those are discussions in themselves)
 - Ignition coil (may need a ballast resistor)
 - Battery
 - Starter (optional - you can run your 6 volt until it burns out, have it rewound, or buy a new one [~$350])  I've run my 6 volt w/o issue
 - Probably a good time to swap out points/condenser for a Pertronix
 - Fuel sender/gauge (I use a small 12v-6v inverter for that and other gauges I want to keep 6v)
 - Fuses
 - Relays (horn, turn signal, whatever you have)
 - Horn will run at 12v, like starter, may burn out earlier and will be much louder
 

I've done it on a few cars.  Depending upon what you choose and who does the work, will cost ~$400-$700


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Post Options Post Options   Thanks (0) Thanks(0)   Quote WeeWilly Quote  Post ReplyReply Direct Link To This Post Posted: 19 June 2018 at 4:38pm
There is a good article in the last Military Vehicle Magazine  by Bob Muller on converting 6 volt systems to a 12 volt starting and charging system and  leaving every thing else 6volt by using a 30 amp step down  transformer and alternator.

   Jim
47 CJ2A (Ranch Hand) 48 CJ2A, 48 Willys truck, T3C 3782, M274 (Military Mule)
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CAL View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote CAL Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2018 at 7:27am
Thanks for the information one other reason for considering changing to 12 volt is my battery will not hold a charge and the gauge shows it charging does anyone else have this problem and is there a way to fix this?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Rus Curtis Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2018 at 11:07am
Originally posted by CAL CAL wrote:

...battery will not hold a charge and the gauge shows it charging ..... is there a way to fix this?
 
Not holding a charge is only one symptom of a bad battery.  IF your gauge is accurate and your system is charging, you could assume the battery has gone bad.  How old is the battery? 
 
Be sure and have both checked out.
 
One "shade tree" method of testing a charging system is to disconnect the negative cable while running.  But since the generator needs a few rpms to charge, you'd need to rev a tiny bit (throttle knob).  Typically, the high beams and heater would be on to create a load when doing this. 
 
If the vehicle continues to run, suspect the battery.  If it dies, at the least there is a problem with the charging system.
Rus Curtis
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1954 CJ3B
Bantam T3-C
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Post Options Post Options   Thanks (0) Thanks(0)   Quote harvey45 Quote  Post ReplyReply Direct Link To This Post Posted: 21 June 2018 at 9:37pm
another reason your battery may not be hold a charge is voltage regulator is not Polarized not charging your battery

Edited by harvey45 - 21 June 2018 at 9:39pm
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