I will re-check whether my charging solenoid closes when the key is turned to "on" and not yet turned to "start"
Yesterday I had the voltmeter on the small wire that goes in the middle (sometimes seen called "ignition wire") and it only showed battery voltage coming onto it after the engine started, but I will re-test. I had the pos probe on the ignition wire terminal in the middle of the solenoid and the neg probe on the battery neg post.
This time I will also compare battery and house voltages to see if there is any action once the key is turned to "on" and left there.
When the starter is started the blower etc quit to reduce the draw on the engine battery and then the key goes back to "on". So it seems that power cut to the other things includes cutting power to the "ignition wire" on the solenoid to open it, and then it closes when the key goes back to "on" and power is restored to the other things too.
So even if the solenoid is closed when you go to "on" that still leaves only the engine battery to start the starter and then after that the house batts are put in parallel with the engine battery.
I saw no voltage drop on the house batteries when the engine is starting, only the rise after the engine got going. If the solenoid does close when just in "on" and engine not running, then I would not see that at the house batts, because there would be no load from the starter.
Perhaps it would achieve the same thing if the solenoid's ignition wire got its power directly from the alternator.
I remember that you are not supposed to leave the key in "on" with the engine off because it will burn out the points. AFAIK there are no points anymore but vague on that. So I hope today's test does not burn my points if I have any. I will report results of the re-test later today.
