12v Battery critically low (msg)

[kanelynne]

Hi, my wife and I have been away for our first weekend in our new Marco Polo, and after arriving at our chosen forest campsite (no mains power) and setting up, all was well until approx 24hrs in when we received a msg saying that the 12v main vehicle battery was critically low. We started and ran the engine for a while and the error stopped but came back in about an hour. This time we left it and eventually the electric side door stopped working. We had enabled the ‘Camper Switch’ on our MBAC App so I struggle to see what would be drawing so much power from the vehicle battery when parked ‍

The leisure battery reported 90% charged when the vehicle battery reported low voltage.

There must be something that we are doing wrong at this point, otherwise the leisure battery is almost redundant.

Has anyone experienced the same and is what was your solution?

Thanks
Kane

 

[Tony Bartlett]

Does it make any difference if you leave the key in the ignition? Does this mean that you're using the main battery until the key is removed?

 

[kanelynne]

Hi Tony, we only have a start/stop button on our MP and therefore it isn’t so definitive as having a physical key removed. The dash lights up and pings at various times including opening the side door to tell us that the roof is open - a bit strange considering we are camping and have the Camper Switch enabled.

 

[mitchello]

This happened to us on our first trip in May. It turned out the fuses for the leisure battery had been replaced incorrectly by a garage and the functions normally served by the leisure battery (eg fridge) were drawing from the car battery. It took about 2 mins by an expert to solve (the garage paid for it).

 

[kanelynne]

This is interesting, thanks for the info, we will investigate with the dealer

 

[Al06]

Hello ! I had the same problem, main battery didn't start engine, dashboard black, electric rooftop stopped at the middle of its way back to flat...Fortunatly our campside had a battery booster to help restart the engine and get the rooftop back again. The secundary battery xas 100% before failure. I cant see any explanation. The main battery was changed 2 years ago.
I deed 45000km during the last 30 months.
By the way how do you check the loading of main battery ? Thank you for your answers.
Alain