New Stator Voltage Seems Low

I just installed a brand new stator in my B&S 15.5 HP Intel Model 28 Engine # 285H77 0122E2 and I'm only pulling 20 volts AC off of it. Is that enough to keep a battery charged when run through a regulator? Seems low compared to what I read. Also, when I put a copper jumper i nbetween the Regulator output (red wire) and the battery, it reads only 12.5VDC which again seems low for a new stator. I would expect at least 13 or higher. The funny thing is that I just replace the voltage regulator a few months ago, so it's basically new. Thoughts?

Two things come to mind, what is the part number of both the stator and regulator. I’ve seen people who have not matched the two together, retired connectors or force connections. Second, how did you test the AC volts.

You want 13.5 volts on the output side of the regulator tapering to 12.5 as the battery becomes charged. I think 20 volts ac is low but what is the output on the back side of the rectifier?