How do I increase voltage for 8V batt on by B?

With a simple 2 wire cutout relay system theres nuttin you can do or need to do to try n charge that 8 volt battery. If you have plenty of charge indicated on the ammeter, she must be charging okay unless theres a short somewhere or the battery is bad. If all is okay and the battery (NOT a short or loads only) is drawing charging current, the voltage must be greater then the 8.4 volts of the battery. Its NOT what the genny puts out open unloaded that counts, that dont tell ya very much. Its what the genny produces when coupled up to a load (like a battery in need of charge) that counts and if shes drawing amps the battery voltage ought to be rising from 8.4 to 9 and better if all is okay n wired correct that is. Im NOT a fan of 8 volt systems.

John T

Within limits, a 6 volt 3 brush generator + cutout setup might almost be considered an ideal current source. Ie. it will deliver approximately the same output current whether the load is at a nominal 6 volts or 8 volts (or 12 volts for that matter...)

However from a practical standpoint, the higher the voltage the greater the RPM required before the generator will begin to charge. Also higher voltages cause faster internal heating of the generator.

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Also.....same as you am I am not a fan of 8 volt batteries! I regard it as a "band aid" solution to an electrical deficiency elsewhere on the tractor. Better to spend $$ to find/fix the underlying problem than toss in an 8 volt battery.

Far as Im concerned if the system has EITHER a simple 2 wire cutout relay orrrrr rrrrr a Voltage Regulator with ONLY a current control relay (the early 2 coil VR's) she will still in theory charge an 8 volt battery buttttt ttttt ttt if its one of the later 3 coil VR's that has a seperate Voltage Control Relay in addition to the cutout and current regulator relay,,,,, ,,,,,it (voltage relay) would need to be tweaked up before she would charge.

Put that in yer pipe n smoke it lol

Take care sparky

John T

If the ammeter shows a strong, continuous charge it's likely the generator is providing the 9-1/2 volts or so the battery needs. You can verify by sticking a voltmeter directly across the battery posts when the ammeter is showing charge.

Now if the battery goes dead after sitting a couple months the problem's the battery itself - time for a new one.