Positive or Negative Ground When installing a battery wit...

gdtractor

Member
So .. with a mag totally separate from the battery .. does the positive on the battery go to the "hot" side of the starter and put the negative
on the battery as the ground?

On my JD H with a mag .. putting a starter on it .. and wanted to know if a negative ground would interfere with the mag?



Thanks

Gary
 
It shouldn't matter a bit, totally separate systems. What will matter is if you include a generator or alternator as they will be setup for charging with one or the other.
 
Mag won't care, neither will the starter. Your charging system will drive this one.
Are you using an alternater? That would be negative ground unless you use some exotic positive ground one.
Or generator? You could technically wire it either way depending on generator and regulator. You will have to polerize the generator, make sure you follow instructions or you'll let the smoke out of something.
 
Are you going with a factory starter setup or something else to spin the flywheel.
Been thinking up a starter for my 42 H that uses a friction drive for to starter on the flywheel.
Richard
 
ALLLLLLLLL Two Cylinder Deere's were originally POSITIVE Ground.

THEREFORE, the battery + goes to frame and battery - goes to the hot input side of a starter switch or solenoid etc.

The Magneto has nothing to do with the battery or ground, it doesn't know or care as it generates its own electricity.

NO, Pos or Neg ground will NOT interfere with a magneto.

DO NOT attach any battery power to it. It may or may not have a kill switch circuit/terminal which when grounded to frame
kills the spark.

The starter will still turn at same direction regardless of battery polarity.

To be safe Id polarize the generator prior to start up

In the event you did switch over to NEG ground (I wouldn't) the ammeter (if it has one) would need its leads swapped and
generator properly re polarized prior to start ID LEAVE IT AT THE ORIGINAL POS GROUND

If I missed anything hopefully the other fine gents here can add to this

John T
 
I have a couple of JD "H" tractors. One is a hand crank and the other has the factory electric start. There is no charging system on the hand crank model because it does not need it but the electric start model has a battery hooked up as a positive ground. If your H does not have a charging system than it does not matter which post that you use for the ground.
 
What everybody else said and think of a magneto as a complete separate system having nothing to do with lighting ,starter, generator circuits. It is self contained ignition. The mag generates AC power for spark within the unit. No batt power ever goes to a mag.
 
A mag has nothing not do with the battery but if you have a charging system on it and it is an alternator it sure as heck cars which way it is hook up and if you hook an alternator up wrong it will smoke the moment you hook it up
 
Thanks everyone for the information .. I appreciate it !!!

The fact that the mag is grounded to the block (isn't it?) ... and has points .. I was just wondering if hooking up a battery would interfere with that [like a "shut off switch by grounding the mag" .. ] ...

it actually has a starter and generator on it .. I just couldn't figure out in my mind which way to hook up the battery . :) ...

I had to buy another mag and the battery was bad ... but I didn't notice the way it came out . (i know . I should have taken a pic or noted the hookup!)

The battery is so old .. it must be bad .. it won't fire .. YET ..

Thanks again ..

Gary
 
" ALLLLLLLLL Two Cylinder Deere's were originally POSITIVE Ground."

JOHN ! you forgot about all those made with 24 volt systems. LOL.
 
Gary, thanks for the update, I think I already answered all your questions but just to be sure here goes again:

1) The fact that the mag is grounded to the block (isn't it?) ... and has points .. I was just wondering if hooking up a battery would interfere with that [like a "shut off switch by grounding the mag" .. ] ...

NO it WILL NOT interfere. As I posted below your tractor was originally POS Ground, so if you're using a Generator (NOT an alternator) Id hook the battery + to frame and - to the starter and I would polarize the genny before starting.

2) it actually has a starter and generator on it .. I just couldn't figure out in my mind which way to hook up the battery . :) ...

POS to frame - to starter if you want to keep it original and it has a generator NOT an alternator. It will still work at Neg ground and starter still turns same direction and will charge if the genny is polarized and its has the correct voltage regulator etc. but if it has an ammeter its leads need swapped


3) The battery is so old .. it must be bad .. it won't fire .. YET ..

The battery (good or bad or dead or hot) has nothing to do with whether or not the mag will fire

You may want to re read my post below once more, it and this pretty well addresses most of your potential issues

John T
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top