incorrect battery installation

farmallaandc

New User
I just bought a 1944 Farmall A and I discovered the new 8 volt battery had been installed with negative ground. My question is has this done any damage to electrical system and do I just make it a positive ground. As you I'm sure can guess I'm new to the tractor world. Thank you to anyone willing to help me.
 
(quoted from post at 07:27:13 01/19/20) I just bought a 1944 Farmall A and I discovered the new 8 volt battery had been installed with negative ground. My question is has this done any damage to electrical system and do I just make it a positive ground. As you I'm sure can guess I'm new to the tractor world. Thank you to anyone willing to help me.
Is it possible your tractor was converted to negative ground? Are you sure the battery is 8 volts and not 6 or 12 volt?
 
Before changing it, do some investigating.

Does it still have a generator, or has it been converted to an alternator?

If it's been converted to an alternator, it will need to remain negative ground, and the 8v battery will have to be replaced with a 12v. Don't run it with the wrong battery, it will overcharge an 8v, could cause the battery to explode!

If it still has a generator, the polarity is not important as long as the generator is polarized to however it is connected. To polarize the generator, simply touch a wire from the non-grounded post of the battery (positive post if leaving it negative ground) to the "A" terminal of the generator. Just spark it, don't leave it connected.

Have you had it running? And is it charging? And what voltage is it showing?

You will need a volt meter to test it.

Check the voltage (and polarity) across the battery. I say polarity, because not knowing any history, it is possible to fully discharge a battery and charge it backward. Look at the voltage, see what it is not running. A fully charged 8v battery will be 8.5 volts.

Start it up, bring the RPM up to 1500+.

Check the running voltage. If there is no increase in voltage, it is possible the regulator was not adjusted up for 8 volt use.

Try disconnecting a battery cable. If the engine dies, it is not charging.

If it keeps running but the volts drops to around 7 volts, the regulator needs to be adjusted up to meet the 8 volt needs.

Do this and get back to us.
 
(quoted from post at 08:18:38 01/19/20)
(quoted from post at 07:27:13 01/19/20) I just bought a 1944 Farmall A and I discovered the new 8 volt battery had been installed with negative ground. My question is has this done any damage to electrical system and do I just make it a positive ground. As you I'm sure can guess I'm new to the tractor world. Thank you to anyone willing to help me.
Is it possible your tractor was converted to negative ground? Are you sure the battery is 8 volts and not 6 or 12 volt?



the battery was replaced because the other was stolen.The business I purchased the tractor from said they put a 8 volt in the tractor because it has more cranking power. I dont know how to tell if it was converted to negative ground. It is still a 6 volt system. all the lights still work.
 
Going with an 8v battery will only be an advantage if the regulator is adjusted to a higher voltage, up around 9.5v.

Otherwise it will operate as a partially discharged 8v battery only delivering about 6.5 volts.
 
I polorized the generator to negative ground. It is charging at 7 now. I will have to get a new regulator before I will be able to step up the amps to your reccommended setting as the regulator has been painted HEAVILY and will not open to give me access to the adjustment screw. I want to thank you so much for your help.
You'll never know how much I appreciate it.
 
Unless you have some modern power-hungry stuff installed on your old tractor the 7 Amp charging rate is likely just fine.

NO need to "fix" something that isn't broke, IMHO.
 
(quoted from post at 00:17:54 01/21/20) Unless you have some modern power-hungry stuff installed on your old tractor the 7 Amp charging rate is likely just fine.

NO need to "fix" something that isn't broke, IMHO.
ome are always looking for something to "fix" or rather to damage.
 
A 6v battery should spin your A over with no problem if the cables and starter are in good shape. 6v in an M is a different story.
 
Yes it should spin like a 12volt. I have my W9 all original and 6
bolt spins it over like nothing , 335 cu.in. I have heavy cables.
 

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