John Deere Model A - 6 volt or 12 volt

[JDx32]

I recently purchased a 1951 John Deere Model A tractor. I used to own a "B" model. That model featured a 6 volt electrical system. Checking the specs on the Model A, it says it's a six volt system as well. However, when I checked the battery compartment, it had two 6 volt batteries ganged together in SERIES, which means it's providing 12 volts to the tractor. So, I'm a bit confused - is the system really a 6 volt system or not?? Did the previous owner screw up and connect the batteries in series instead of parallel?

 

[bcp]

Some used 12 volts on purpose because it spun the starter faster. They changed light bulbs, if any, to 12V. That kind of thing used to be common after 12v systems were introduced.

Either way is better than using the steering wheel.

Bruce

 

[Raised on a Deere]

The generator plate should say. Can't juice up a 6 volt system by hooking two 6 in series and have it charge without changing the gen. The starter might tolerate it. My best memory is that it is 12 volt. Dad had a 1950 and I recall a lot of people being impressed with the starter. It started good in cold weather.

I love the poppin john.

 

[bcp]

This mentions in post #6 that late A's were 12 volt.

John Deere A Generator Help - SmokStak

Bruce

 

[JDx32]

Thanks Bruce. You are so right - it's much better than using the steering wheel!

Are there any issues with the generator being a 6 volt system and having the batteries ganged together as a 12 volt system?

 

[Diamondpilot]

Thanks Bruce. You are so right - it's much better than using the steering wheel! Are there any issues with the generator being a 6 volt system and having the batteries ganged together as a 12 volt system?

Stronger voltage wins.

Easy test is put a multi meter on it and measure the voltage. Say it's around 12 volts. Now start the tractor and bring it up to operating RPM. You should see 13 plus volts, preferably 14 volts, if the gen is indeed set up for a 12 volt syste. Remember, highest voltage wins, so the gen must be slightly stronger than the batteries. If it were 6 volt gen it would actually discharge the system as it ran.

Chris

 

[Raised on a Deere]

Thanks Bruce. You are so right - it's much better than using the steering wheel!

Are there any issues with the generator being a 6 volt system and having the batteries ganged together as a 12 volt system?

It will fry something (exactly what depending on what type generator you have). Never done it but I heard about it blowing fuse, diode or winding. It is possible that nothing would be hurt but that there will be no ability to charge. Ours had a Delco gen 12v.

 

[CobyRupert]

However, when I checked the battery compartment, it had two 6 volt batteries ganged together in SERIES, which means it's providing 12 volts to the tractor.

In SERIES, as in the pos (+) terminal of one battery is jumpered to the neg (-) of the other right?
What doesn't make sense, is if they're running it as a 12V system, why use (2)-6V batteries instead of just one common 12V battery?

 

[grnspot110]

In SERIES, as in the pos (+) terminal of one battery is jumpered to the neg (-) of the other right?
What doesn't make sense, is if they're running it as a 12V system, why use (2)-6V batteries instead of just one common 12V battery?

More staying power! All the 12V JD two-cylinder tractors originally used 2-6V batteries & the diesels with 24V starters used 4-6V. The 1953-60 I grew up on used 2-6V & the 58-720D ES had 4-6V. Now, I would be using 12V batteries in place of the 2-6's!