Lots of good information in this thread so far.
I am self taught and most of my knowledge comes from the late 1980's era GM 4.3 v6 with TBI. I know this is a different animal but that is what is in the car that got me into this hobby. Now I am working on a 41 Master Deluxe with the original 6v system.
My charging system knowledge was that the alternator at all times supplied enough power to run the engine and car's electronics. Any excess was used to charge the battery. The output of the alternator should should be enough to do this plus a percentage incase added draw is required at any time.
That is correct.
Now I thought a generator was just a did the same thing but with a different technology. I thought all the same rules applied,
Yeah, pretty much.
then I asked a question in another thread and received an answer that made me realize how wrong I may be. Rusty 37 stated, 'Remember that a generator provides no output at idle.'
He's right. It might provide no output at all, or it might provide a tiny bit. You sure wont get half the rated output like you would with an alternator. Assuming we are talking about your 41, or any of the large 2-brush generator systems with a 3 relay regulator that became common around 1940, it is 99% a non-issue. You will never know the difference unless you are some outlier that is commuting at night through a million stoplights in the rain with the lights and radio on and the defroster on high. Even in that case, your regulator could be turned up a tiny bit and you would probably still be fine.
Now I have the following questions:
1. At idle is the generator or the battery providing the power to run the engine. I.E where is the power to the coil coming from?
Either or both. It all comes from the charging system as long as there is enough being generated. If the charging system cant keep up, then some comes from the battery and the overall voltage is lower.
2. Will the car drain the battery if left to run at idle for an extended period of time?
If the radio or lights or something are on, then yes, definitely. With just the ignition probably not. Ignition doesn't draw much. Maybe 2 amps? maybe 4? If the generator is charging at all, and the cutout is pulled in, it would probably just carry it, or at least most of it. If the cutout is not pulled in, the battery would have to carry it. It would discharge according to it's amp/hour rating. I think you would run out of gas first, even if you had a full tank.
3. Does the battery only charge while driving?
Yes, as described above. It might or might not charge at idle, but if it does, the amount will be negligible.
4. What is the difference between 40 amp at 6 volt and 40 amp at 12 volt?
To do work, you need watts(power). Multiply volts(they're kind of like pressure) times amps (they're kind of like flow) to get watts. 40 amps at 6 volts can do the same amount of work as 20 amps at 12 volts. 40 amps at 12 volts can do twice as much.
I was just adding up the amount drawn by each item at once and making sure it was less than 40.
Yes. That is exactly how you do it. You want more amps available than what you will use. There needs to be some left over to charge the battery.
5. How many amps are used by the engine?
I should know this but I can't remember. I'm gonna guess about 2 to 4 amps for a points ignition. Oddly this is about the same on 12 volt cars.
6. How many amps are required to maintain the battery?
That one's tough. It varies. A battery wont draw much when dead. After it gets partially charged, it will draw a bunch. When it gets close to full, it tapers off. It really doesn't take much at all when the battery is full. If it's down, it will draw everything it can. If there's not much current available it might take a really long time to get back to a full battery and completely normal system voltage.
7. The amp meter appears to work, I only watched the gauge while idling the car. I noticed it was on the charging side and thought nothing of it being steady. Is this how it should be?
The ammeter shows flow in or out of the battery. If it is showing charge it is keeping up, because flow into the battery means there was at least something left for the battery. If it shows discharge, the system is not keeping up. Things will dim, and eventually run down. How fast it runs down depends on how much discharge, and on the amp/hour rating of the battery.
8. I keep the car on a 6v trickle charger with a battery disconnect disconnecting the car from the battery at all times other than when working on it. Is this the best practice?
Yes. Preferably a maintainer, not a plain old fashioned trickle charger.
It is one of the quick connects with a dial to connect the battery. I use the same one for storing my Monte Carlo in the winter.
The ones I have had and seen were crap. I like the idea, but haven't come up with something good enough for a 6 volt car. I'm looking into it.
I am currently in the stage of wiring everything. I am using copper wire (not copper clad) and replacing with the same awg or larger. I was under the impression that a 6 volt system would require a larger wires than a 12 volt system. Is this correct?
Yes. Twice the current (amps) for the same work. Amps being flow determine wire size.
All the wiring in the car was larger than that in my current one so I thought it must be correct. Sorry for the long post. I and my kids are learning as we go. We knew we were up for a challenge getting into this. Unfortunately we seem to spend 50% of the time on the planning, 20% finding parts, 20% working, and 10% wasting time wondering what we just did.
Have fun with it!