I am not sure switching from 6v to 8v battery is a good long-term solution. If the generator cannot keep up with the load, the net result is a dead battery.
Said another way, if the generator does not have the capability to run the headlight system.... it certainly does not have the ability to charge a battery at the same time.
It would be FARRR better solution to use LED bulbs (everywhere possible) which use about 1/3 less
power.
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Another possible solution.... go ahead and adjust the 3rd brush to increase generator output. Wire in a DEDICATED regulator to keep the 6v battery maintained.
From an electrical point-of-view, it seems to me that the REGULATOR is the real issue.... the generator is capable of delivering the current but the regulator does not maintain the proper 6v voltage.
Heck... just using a higher AH 6v battery may be a good solution. (golf-cart battery) this would allow running longer periods at low RPMs (not charging) .... as long as you keep the battery on a trickle-charger when parked.
Another Question: is there a 6v engine-starter... or is the engine hand-cranked?
(I am trying to understand the function of battery in that electrical system)
The engine has an electrical starter and a hand crank. The engine has a magneto and a generator. The magneto was used to run the engine while the battery was used to electric start the engine and to run the headlights. The engine can start and run on magneto only, or battery only. The key switches from one system to the other. In normal circumstances the engine is run off the magneto only whereas the lights are always normally run off the battery.
In its original design the battery was used to make starting easier than using the hand crank but the engine was rarely run off the battery. A scenario where the engine would be run solely off the battery is if the magneto was damaged or a wire broken. That would be the exception rather than the rule. The charging system was never designed to run the engine and the lights full time. Since the generator is connected directly to the engine crank via a direct gear, the generator is only turning at the same exact RPM that the engine is turning. There is no way to speed up the generator like pulley driven ones can be.
The lights normally run on battery only. However, it is possible to convert the lights to run on magneto only, if I had the magneto light bulbs. Those bulbs are much higher voltage to handle the magneto voltage output.
In short, the charging system is doing exactly what it is designed to do. There is no fault that I am trying to cure. By me running the lights full time, and the engine running at only about 1400 to 1500 RPM max, I am demanding more from the charging system than it was ever designed to do. I was simply wondering if there would be any advantage to using a higher voltage battery to be able to run the lights full time. The proper answer is to get light bulbs that draw less current. I already ordered some 6 volt LED light bulbs last month, but they are taking the slow boat from China. Once they get here, I am sure that they will do what I want them to as far as the charging system is concerned.
I was originally asking the question because it looks like the light bulbs will not arrive before my tour and I have access to an 8 volt golf cart battery as a possible temporary solution for this one tour. I was wondering if I would be possibly damaging a battery that did not belong to me. It looks like that would be the case so I am not going to risk it.
