6v or 12v system?

MikinInd · Sep 15, 2015

I have a 44 John Deere A that came to me with a 6 volt battery in it like it would have had from the factory. I was told it was a 6 volt from the guy that sold it as well.

After looking it over the noticed that the generator tag says 12 volts on it. It also has a later distributor in place of the mag.

How do I know what I really have here?

Dalex · Sep 15, 2015

What kind of battery do you have in it ? 3 caps is 6 volt , 6 caps is 12 volt

Dalex · Sep 15, 2015

oops , missed your mention of it being 6 volt battery. I'm going to say it's 12 volt and they put the wrong battery ....

Steve@Advance · Sep 15, 2015

Look for other clues, like lamps, coil, etc. Lamps will have a number that can be crossed, some have the voltage on them.

If it is still six volt, it should be positive ground.

Since it has a coil, need to check that out anyway to see what you have. A 12v coil set up will have 3 to 5 ohms across the terminals, a 6 volt will have 1.5 to 2 ohms. Disconnect it to get a true reading. If there is a resistor, leave it connected and test through the resistor to the opposite terminal.

I believe the 12v generator will work as a 6 volt if the regulator is set for 6 volts. Someone better check me on this though...

If it will run, start it up, bring the throttle about half way, check the voltage across the battery, see what you get. If it's charging around 8 volts, you're good to go. If it's trying to push 12-13 v to the 6 v battery, it is set for 12v.

RM-MN · Sep 15, 2015

Generators don't care what the battery voltage is, they just produce electricity. Without a voltage regulator on them, they can produce up to about 100 volts. Your regulator is what makes the system a 6 volt or a 12 volt. If you have a 12 volt regulator and a 6 volt battery, the battery acid will soon boil away.

gene bender · Sep 15, 2015

Then why did they make 12v gens

John T · Sep 16, 2015

Actually the faster the generator spins and/or the more current you pump through its field coils the more energy it produces. I have used 6 volt gennys to charge 12 volt batteries simply by using a 12 volt voltage regulator HOWEVER the field current can be different in a factory 6 volt versus a factory 12 volt genny, THEREFORE if a shop changes a 6 volt for 12 volt operation they could change out the field coils to accommodate more current and resultant heat.

Its true a 6 volt genny can be made to charge a 12 volt battery by passing more current through its field coils, but its also true they are NOT the same gennys out of the factory and the field coils and armature ratings can be of different rating and design.

Hope this helps

JOhn T Retired Electrical Engineer

John T · Sep 16, 2015

FYI ALL two cylinder Deeres were Positive ground, BOTH 6 and 12 volt, unlike IHC.

John T

ss55 · Sep 16, 2015

You might want to ask this question on the Deere forum. I think the late A's, with the battery box under the seat, used two six volt batteries in series on a twelve volt system. I don't know about a '46. At seventy one years old, anything could have been changed several times by now. Check the tag on the starter, or get a service manual to be sure what the original voltage was.

6v or 12v system?

MikinInd

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Dalex

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Dalex

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Steve@Advance

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RM-MN

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gene bender

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John T

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John T

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ss55

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