Farm Equipment - CA Electrical Problems (?)

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CA Electrical Problems (?)

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Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=48550
Printed Date: 27 Aug 2025 at 8:35am
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Topic: CA Electrical Problems (?)

Posted By: PA Bill
Subject: CA Electrical Problems (?)
Date Posted: 06 Apr 2012 at 6:11am

I bought a CA which the previous owner had converted to an alternator.

For reasons I can't explain however, he converted it to a 6 volt rather than a 12 volt which is certainly more common.

When I first got it I noticed that I couldn't keep the battery charged. So I replaced it but that didn't fix it. Still wasn't charging.

But before I could get serious about looking into the problem, I was driving it the other day and it just flat died and a fully charged battery won't even turn it over. Just nothing going on.

One thing I noticed is that whoever did this has it set up as a negative ground, and I know that originally they were positive ground systems. So maybe he put the battery in backward and that's part of the problem.

Bottom line, what would you do here? Rip it all out, put the new battery in the G and convert it over to 12 volts? Go find a new 6 volt alternator? Turn the battery around?

I really don't know what makes sense at this point.

Any thoughts?

Replies:

Posted By: DonDittmar
Date Posted: 06 Apr 2012 at 6:20am

Switching to negative ground is as simple as switching the bat cables, distributor leads, and ammeter leads. Maybe they switched the battery to neg ground but didnt switch the ammeter leads, which would show a discharge when they are actually charging.

If a fully charged battery wont turn it over, you need to correct that problem first, either a starter issue or maybe cables.....if you have an amp clamp put it on the pos battery cable going to the starter and try to cank it over and see how much current the starter is drawing.

Once you have that figured out, I would switch it all over to NEG ground 12 volt and be done with it

BTW, I GEN will charge pos or neg ground, it doesnt care. all you have to do is re-polarize the regulator

An alternator can be made to charge pos ground, but you have to dissassemble it and change out the diode and heat sink

-------------
Experience is a fancy name for past mistakes. "Great moments are born from great opportunity"

1968 D15D,1962 D19D
Also 1965 Cub Loboy and 1958 JD 720 Diesel Pony Start

Posted By: DonDittmar
Date Posted: 06 Apr 2012 at 6:21am

If the starter wont crank it over, it may be a mechanical issue with the engine as well......something may have it bound up

-------------
Experience is a fancy name for past mistakes. "Great moments are born from great opportunity"

1968 D15D,1962 D19D
Also 1965 Cub Loboy and 1958 JD 720 Diesel Pony Start

Posted By: Steve in NJ
Date Posted: 06 Apr 2012 at 6:34am

Most Alternators are Negative ground. As Don said, if the engine isn't turning over with a full Battery, that issue you need to find first. I've built and sold a few 6V Alternators and they work fine for folks that own Model A's and so on that don't want to change the whole electrical system over in a car. Tractors are easier to flip to 12V mainly because of the simplicity of the unit. The choice is yours which way you want to go. I always tell our customer's, if its a working Tractor, and you need extra lighting on board or electrical accessories, the 12V system is the way to fly. If its a hobby tractor and you use it on occasions around the property, the 6V system works fine in that catagory. As I said the choice is yours. We offer either 6V or 12V conversion kits for your Model CA if interested. If you need any help or info, be glad to help you out...

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