Help analysing voltage readings

[Mervmaster 0]

My 91 416-h isn't charging.   The battery holds power for a couple weeks of starts, but I'm getting nothing once it gets low.  

 

At the regulator, I read battery voltage from the middle prong to ground (12.4 or so currently), and on the outsides I read 27 at idle, up to almost 50 at high rpm. 

 

What does this mean?  I'm no mechanic but I think I'm either reading way too high from the rotor, or its not getting through the regulator.  

 

 

Thanks guys,. I love this forum.  

[rmaynard 14,922]

The alternator under the flywheel produces AC voltage. You should check it with the wires removed from the regulator. Typically it should read 38 to 45 VAC at 3600 RPM. When everything is hooked up, you should check the DC output and find about 13.5 to 14.5 VDC. Anything less and you won't be charging the battery.

[Mervmaster 0]

15 minutes ago, rmaynard said:

The alternator under the flywheel produces AC voltage. You should check it with the wires removed from the regulator. Typically it should read 38 to 45 VAC at 3600 RPM. When everything is hooked up, you should check the DC output and find about 13.5 to 14.5 VDC. Anything less and you won't be charging the battery.

So, with everything plugged in, and the motor running, I should read above the current battery voltage when testing the middle terminal of the regulator?

 

Cause right now my battery reads 12.6 and my regulator reads 12.6.   I guess I'm not sending power?

[rmaynard 14,922]

That's too low to charge the battery. I would try a new regulator. Common problem with that charging system.

[953 nut 51,915]

Clean and inspect all electrical connections including grounds and fuse holders, they can all rob voltage.