John Deere lawn mower charging

I bought a gt235 John Deere lawn mower this summer. I really like how it cuts. But the battery light has been on and off.

So today during the rain I thought I'd clean up some small projects. This being one. I got my tester out. Tested the two wires coming from the fly wheel. 30 to 32 a.c. volts at a little less then full throttle. That should be good.

I tested the wire going to the battery. I had 12 volts there so I knew the wire was good. Started the mower and again I only had 12.4 volts.

Ah ha regulator is bad. I go get one from a junk mower. Put it in. Light is still on grrr. Bad regulator? So I tested the battery with it running and I have 14.2 volts at mid throttle. So that would say my regulator is good.

What might be keeping my battery light on.

jaybmiller wrote: bad battery ? won't take a charge( bad cell)... swap out the battery. put old one on bench, measure it, then put on charger for 2-3 hours, it should read at least 13-13.5 volts. I toss an 1157 lamp on it after being 'charged' to get rid of the 'surface electrons' then read the DVM....should be 13.5-14 volts for a good battery. let sit overnight, if lower in the morning odds are a bad cell...

I never thought of or heard of that before, but a great idea!