Beach Parking Heater blowing cold

[kave]

Just try and start it again. Ours does this from time to time, can’t see any connection between battery level.

 

[MattBW]

The battery was showing as 11.8v which is the low power cut off in the heater. It won't start below 11.8. I am confused why it was 11.8 however as I drive it every day and have no drains other than a GPS tracker