Hi everyone, I'm new to the forum, this is my first post. I tried a search but was unable to find an answer. I have a 1994 Troy-Bilt garden tractor with a 16 HP Briggs & Stratton engine. I was mowing the lawn today when the battery went dead. I put it on the charger and it charged back up (13v). I finished mowing and it was low again (10v). Is there any common problem that would cause this, regulator, ect...? How can I test the system? Thanks in advance, Terry.