I recently replaced the r/r on my 2003 vn750. I checked the stator with a meter and it checked good. my question is this I can jump start the bike with a riding lawnmower battery but when I pull the jumper cables off it goes dead. the battery on the bike is bad( only has about 10.8 volts. does the bike have to have a good battery to run even if the charging system is fine.