Great info as usual Mark. I didn't actually run the battery dry, it was just a bit below the low mark, but it was only reading around 2.7 to 3 volts. When I charge it up now it charges up to 6.8 fairly quickly, but it seems like after I ride for a while it's around 6.3. However I'll see how it goes now with my different setup. The battery is a Yuasa.

I'll look up the procedure to test the charging system. If I get pulled over and the cop wants to see if my tail light will stay lit for 15 minutes, I'll just secretly keep my foot on the brake pedal :0)

My main issue is just having daytime running lights working, and the battery not dying. I'll never be riding at night.

By the way, it wouldn't be difficult at all to wire my tail light so  I can switch it from magneto to battery. I really like having it on the magneto, but a simple switch would allow me to quickly transition it to battery if I needed to. Not that I'll ever have to, unless I'm forced to prove that it will stay on for 15 minutes without the engine running.

You’ll need to take the 3-way pickup switch out of yer Les Paul.. you can go from day time to night or both configurations!
Sneezles61

"You’ll need to take the 3-way pickup switch out of yer Les Paul'

 I'll bet there's a way to wire it so when the engine is running the tail light is powered by the magneto, then when the engine shuts down it switches over to battery. Maybe with a solenoid powered by the magneto, so when the magneto stops it switches to battery?

I'm not sure if it would be worth the effort though. In fact during all of my trips to the DMV and CHP to get the bike registered and titled, no one asked me to start it up, or wanted to see if the lights, horn or anything else worked.

By the way, I'm a Fender guy 

That was a long time ago.  California cops would pull you over just to do "safety checks" especially near the beach areas.

They even ran roadside safety checkpoints in California like they do for sobriety checks now.  They'd check your paperwork, lights, tires, wiper blades, etc.  If you were riding a bike or driving any kind of "hot rod" you'd almost certainly be waved in for inspection. 

Mark, I live in a So Cal beach town and I haven't seen anything like that in decades. Occasionally they'll set up a sobriety checkpoint, but I've never seen a vehicle inspection set up roadside.

I would be interested if there was a way I could wire this so it would automatically convert to battery if the engine stopped, just for the heck of it. I completely understand the value of having that function, say if you're riding at night and stall at an intersection, at least the tail light would stay on while you're trying to get the engine started, or pushing the bike to the curb.

Best keep it simple…
I’ve got a few of each in my collection…
Might not be noticeable, but the shorter scale of Gibson helps my worn out hands.
Sneezles61

Yeah, the short scale of a Gibson definitely makes a difference. I have some shorter scale acoustics that play a lot easier with heavier strings because of that.

Back to the bike, I found that the regulator was rubbing against the inside of the tank as I was riding, so I decided to change the way it mounted. I rebent an angle bracket, and now have it mounted pretty much under the top tube.

  

I found the problem with the charging. I was checking the battery with it on the daytime and nighttime circuit, and it was just flat on night time. I swapped the wires coming out of the stator, then I was getting really good charging on daytime, but nothing on night time. I figured it must be a loose wire under the ignition switch, and that's exactly what it is. I've just got to resolder the green/red wire. 

 

There you go.  Great job!

Man you guys are good--so good at working stuff out. Be a long time since i've seen 'that' on a switch. One more i've not seen for years is wires breaking inside their casing from flexing at the steering head--main loom wires that is.
Is the site taking pics again or is everyone doing it through a hosting thing.