If my heater shuts off after I’ve started it even with an overnight charge the red led on the side flashes about 3 times pauses and same again,if I drive turn the heater on before when the vans running when I get to the next job it’s working fine and continues to do so the rest of the day.
My issue I’m sure is the batteries due to it drawing a huge amount of amps on initial startup,if I plug into the mains and start the heater up obviously van not running it purrs like a dream with 14.5 volts on the meter,nice to hear your heater is producing something like hot water Daz lol lol.