i have a 97 Winnebago adventure . with some electrical issues , started when generator would not start , then while checking battery voltage ,the coach batteries (2 12 volt in parallel) measured 10 volts , the main battery (12 volt) measuring 29 volts. with engine started all batteries read 30 volts, what would cause the main battery to read that high, also pertaining to generator, i don't appear to have voltage from battery to start solenoid