what would cause a F900EX apu to gon on and offline, with APU running?

  After installation of loaner batteries: This time…. Marty departing Morristown, the apu gen came online. After APU start, APU amps pegged on hard charge. normal. a few seconds later, the needle came down into the green range as expected. then the APU gen went offline, then online…..APU still running fine. during the next few … Continue reading what would cause a F900EX apu to gon on and offline, with APU running?