12 volt battery on 6 volt system

I have purchased a 1955 TO35 Ferguson tractor. It was not running and the owner had put in a new battery but couldn't get it started.
What I have discovered is he installed a 12 volt battery, negative ground, but did not make any other changes. What may I expect to be
damaged because of this?

Probably nothing. Possibly the Voltage regulator could have been fried if the polarity was reversed.
Put a high crank amp 6v battery in it, Check to see if the points got burned up from the 12v and the key left on for a while. Check the fuel and try to start it. (the 6v starter will be fine. Jim

short answer, you will need a 12 volt coil and a ballast resister

Not likely to have hurt any thing. But that said if by chance the ignition switch had been left on the points maybe bad and or coil but if not left on not likely to have hurt any thing. If it still has a 6 volt coil you will need to add a ballast resister liek the O'Reilly's brand VR-1 or VR-2 if you plan to keep it 12 volts

A TRUE 12 volt coil does not need a ballast resister period.
But many coils say 12 volt ballast resister needed so they are really 6 volt coils. But a true 12 volt coil will say right on it no ballast resister needed

If the 6 volt lights were turned on, all bulbs will be burned out.

You ask "he installed a 12 volt battery, negative ground, but did not make any other changes. What may I expect to be
damaged because of this?


If all he did was install a 12 volt battery into a 6 volt tractor (if that's what it was??) but it never started:


1) If 12 volts was applied to an old 6 volt voltage regulator (if that's what it had???) for a long enough time period it could possibly be
damaged.

2) If polarity were reversed (Pos to Neg ground if that's what it was???) and the generator never got correctly polarized, again that can
damage a voltage regulator

3) 12 volts on an old 6 volt coil (IF thats what it had and assuming no ballast was added) can overheat and damage it given enough time, but
if it never started it may well be okay.

4) 12 volts on a 6 volt coil can eventually cause premature points burning if the ignition was left on long enough. (true for even correct
voltage ign on long time not running)

5) Of course if 12 volts was applied to any 6 volt lights (if it had such) they will glow very bright a short time then burn out

If its a 6 volt tractor and has a 6 volt coil you can easily add an external series voltage dropping (12 to 6) ballast resistor (or else toss the old coil and get a new full true 12 volt coil),,,,,,,, get a 12 volt voltage regulator to match the tractors ground,,,,,,,,,,get a 12 volt generator,,,,,,,,,polarize the generator to match the ground,,,,,,,,,,,,,,get 12 volt lights,,,,,,,,,if it has an ammeter and polarity got swapped its leads need reversed,,,,,,,,,,,,,wire coil to match tractors polarity. NOTE I have used 6 volt gennys on a 12 volt system and only changed the VR and it worked

John T

Depending upon how long the ignition was on and if the points were closed, the coil may be damaged.

VR may be damaged.

6V lights will work for a surprisingly long time but will eventually fail if operated on 12V.

Fuel gage and or/sender may be damaged.

Operating a 6V starter from a 12V battery is very hard on the starter nose cone, drive and/or flywheel ring gear. One or the other or both will eventually fail.

Dean

I have a 55 TO35 that came with the 12 volt system from the factory. Sending a page from a 1954 Ferguson TO35 sales brochure.

Bingo, you have a winner. Benj R is correct it came from the factory with a Ground : positive (until 1955), negative (1956 on). Charging system: generator Charging amps:12.
I'm not saying their is no damage to the system, but the new battery is not at fault.