6V Wiring for generator on C

Looking for some guidance on how to wire this 6V generator on my C so it will charge the battery. There wasn't any wiring on this tractor when I got it. Don't plan to run any lights on this tractor. It's my mowing tractor but I do need the charging system to work correctly. The simpler the better.

Edited by AJ - 10 Apr 2016 at 12:57pm

Can it be wired to just a regular on/off switch?

Steve?---what if he removed the cut-out and installed a regulator?---then no switch needed, right? thanks; ac fleet

Yes you can use a 6V regulator, it has the cut out built in. Much better than just the cut out alone.

I have a friend that had his generator die on an M Farmall. He put in a 12 volt battery and coil and has ran that tractor for over 10 years with no charging system. He doesn't ever use lights, but uses the starter and it is battery ignition. Depending on use, he might charge the battery once a month.

With the manual charging control as built originally, battery life is highly dependent on operator attention to not overcharging or undercharging the battery. The charging rate depends on the engine speed, so charging for a fixed length of time isn't accurate. Limited overcharging converts electrolyte water to and explosive mixture of hydrogen and oxygen so the battery needs topping up often. A vintage voltage regulator improves that situation. But its less than perfect because the SAE standard for voltage regulators allowed them to vary from 6.5 to 7.5 volts on a 6 volt system. 6.5 volts won't get the battery fully charged and 7.5 volts will be a certain overcharge. They can be adjusted but stlll have some range. 7.1 volts is the ideal voltage for a starting battery with a 1260 specific gravity full charge. 14.2 for a 12 volt starting battery, a little less for a deep cycle battery. That ideal charging voltage also depends on the battery temperature being lowest at about 68F and rising gently for higher and lower battery temperatures. Starting and charging does warm a battery above the ambient but I don't know of any modern regulator checking the battery temperature (standard practice in Lithium Ion battery packs for computers and telephones). A solid state regulator can hold the voltage to a closer tolerance and vary the voltage according to the regulator's ambient. The first one I built about 1969 did that without my planning for it and significantly extended battery life in that car.

A voltage regulator generally has three terminals marked B, A, and F. Sometimes a fourth marked L. B goes to the battery through the ammeter. The ignition switch connects to the generator side of the ammeter, as does the light switch and other accessories if there is no L terminal. A goes to the armature on the generator, generally the large post. F goes to the field. Both the generator and the regulator must have their cases solidly grounded. If there is an L terminal, the light switch and switches for other accessories connect to L so they can only be run when the generator is putting out power, not with the engine stopped.

The voltage regulator will include current limiting which isn't needed so much for a three brush generator like the original, but isn't harmful to good charging and the cutout. The current rating of the regulator should be about the same as the generator current rating for best generator and generator brush longevity. There are two ways to connect the field, the inside wire either goes to the A post or to ground and each connection takes a different regulator internal circuit. ACs generally have the field connected to the A post so the regulator or external switch connects the field to ground.

Gerald J.