27.5 volts running is what I see on my guages while running. My Chasis batteries run at about 13.7 volts while running. POGIII Rally seminar discussed maintaining a charge of 12.5 volts on chasis maybe 12.25 but thats it. Liberty says 11.7 volts for chasis. I've never seen my House batteries lower than about 23 volts as I always keep the coach plugged in to shore or have my engine running.