I have a small Pete #700798 that I am doing a lease on. I only had it a week so far I have not had any issues with the battery. And I been running up here in the Northwest. I am currently stuck in a snow storm here in Wyoming. I am sure he has a bad cell or could be a bad ground some where draining the battery. That bunk heater dont use that much power as long as you dont have it on high setting all the time.