The 8 Volt Generator Conversion - It is possible to simply install an 8 volt battery and readjust the voltage regulator, so the original generator will put out a maximum of around 9 volts. This requires someone with the knowledge, and ability to properly adjust the voltage regulator. In order to charge a battery the generator must put out slightly more voltage than the nominal voltage of the battery. This is similar to putting air in a tire, it takes extra pressure to push the air into the tire. Add too much pressure, and the tire will eventually explode.
Voltage is basically electrical pressure. Too much current will overcharge the battery, and yes, in extreme cases, the battery could even explode.
ADJUSTING THE REGULATOR isn't too difficult. The adjustment is simple and was often done, on the tractor, with this trial and error method:
Disconnect the BAT lead at the voltage regulator, remove the cover. You should see 2 coils in the regulator. The voltage regulator coil will have just a few turns of wire around it. The coil with many more turns of wire is the cut-out relay. Leave the cut-out alone, it only disconnects the generator at idle to keep the battery from discharging to the generator. The voltage regulator coil is what regulates the charge. All you do is bend the little metal tab to increase spring tension on the contacts. Increasing tension, increases voltage. We are only looking for about 2 volts increase, so give it a small tweak. Reconnect the battery wire to the regulator, start the engine and check voltage. If you went the wrong way, the voltage will drop. For an 8-volt system, the charging voltage needs to be at 8.5 volts when revving the engine. Careful, too high will overcharge the battery.
There are several different regulator designs that might end up on one of these tractors. Some regulators actually have adjusting screws. Others have springs on tabs where you bend the tab up or down to change tension. Look carefully at how the contacts and springs are arranged, sometimes the adjustment is backwards from what seems logical at first.
The 6 volt light bulbs will be brighter and probably won't last as long. On a front-mount you should add some additional resistance in the ignition circuit to protect the coil. Please refer to my comments on the Main 12 Volt Page regarding coils and ignition resistance.
The 12 Volt Generator Conversion - For this one you need to find a shop that will re-wind your generator to put out 14 volts. Then you can use a standard, off-the-shelf 12 volt regulator, 12 volt coil, and 12 volt bulbs.
Positive Ground Alternators - YES, it is possible to convert a normal negative ground alternator to work in a positive ground system. These have been created in both 6 and 12 volt versions. There's probably even an 8-volt version if you look hard enough. My question is WHY would anyone want to complicate life to this drgree? Most people see an alternator and immediately assume it's supposed to be negative ground. By using one of these, it virtually guarantees that the alternator is going to get hooked up wrong at some point and instantly fried.
I guess the lesson here is to just keep it simple and document whatever you decide to do. When I run into one of the oddball systems, it's because the system failed or never worked. My first recommendation is to put the original 6 volt system back on the tractor. If that's a NO, then go with the main stream 12 volt conversion.
No conversion will permanently fix any of the things that will eventually cause any electrical system to fail. The simple fact remains that these tractors do require more frequent maintenance than modern equipment. Open connections and unsealed switches are attacked by the environment and deteriorate over time. If you don't take things apart and clean the connections eventually they will fail. Changing the voltage may increase the time between maintenance but also increases the potential damage that can be caused. More voltage equals more energy to dissipate. Things that just looked dirty at 6 volts are often melted and useless when they fail at 12 volts.
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