Topic: Charging voltage lights on/off?

[zabzob]

I'm checking the charging voltage on my 75 CB750K and getting lowish readings. This is with the headlight on. Should I be testing this with lights off? How much of a difference would that make?

[dave500]

are you increasing the revs?

[zabzob]

Yes. I get 12.4V at idle. Going from 3000 to 4000, it comes up to 13.4 or so, then back to down to 12.9. In the past with the lights off, I've gotten more like 13.9V. Also, after a 45 minute ride last night and a 20 minute ride to work this morning, it's resting at 12.8V. Low, but not killing the battery low.

I've read lots of posts and I'm running through the list of things to check. I've already cleaned all the connections that I could. I'm also waiting on some new blade pins for the alternator/reg/rectifier connections, which are stuck in the on strike postal system. Just want to make sure I'm not trying for an unattainable voltage for a bike with the headlight on.

[Don R]

sounds about right, is there a problem?

[zabzob]

Well, not really anymore. I did have an issue with some melted alternator connections, which I fixed. Maybe I'm just being paranoid, or maybe I just saw other people's 14.5V@4000rpm and got jealous. If it's still low after I clean up the rest of the connections, I'll just adjust the regulator. But then, the question still stands -- should I be measuring voltage at the battery with the light on or off? Does it make a difference?