XC40 battery going flat

[mxr]

I have an XC40 B4 mild hybrid that I bought new in October 22. On two occasions when the car has not been used for 7-10 days the level of charge in the battery has dropped so much that the car has completely shut itself down. The dealership tells me that they can find nothing wrong with the battery and that there is nothing draining it excessively when the car is not in use. They have come close to suggesting that this sort of thing is normal in a modern car. Surely this cannot be correct or no-one would be able to leave their car at an airport when they went away on holiday.

Has anyone else experienced anything similar?

[Ulrikas PA]

No personal experience for your model, but we have three cars including an older V60 hybrid. I put each car on our C-Tek trickle charger overnight, once every month. It has a couple of functions to ensure your battery is always in the best condition for your car.

I agree with what you are saying, but it might also give you some evidence to go to your dealer if it still runs out of charge after 7-10 days.

I started doing this 20 years ago when I managed Mercedes-Benz Roadside Assistance and we were regularly contacted for your airport scenarios. To make matters worse, people were doing jumpstarts that fried the control modules.

[Moose Test]

Originally Posted by mxr

nothing wrong with the battery and that there is nothing draining it excessively when the car is not in use

Given that you experience what you do, both statements cannot be simultaneously true. Unless - the car's power monitoring/management system is at fault and is throwing a false positive for degraded battery voltage/charge state.

A lead acid battery in good condition has a typical self-discharge rate of no more than 10% per month.