So sitting in Waitrose carpark waiting for my wife and message pops up "turn on engine or system will shut down in 3 minutes". Any ideas - had ATS check battery a month or so ago and they said it's ok. MY 09 GS manual in Lago Grey, Wood Co arm rest and side bumper strips - now sold.

MY 15 SD4 SE Auto Orkney Grey with colour coded Bumper Door Mouldings

Standard behaviour in many cars. Trying to save the battery from flattening because you’ve left the radio on in an unlocked car. If you lock the car it will shut down un-needed electronics after a few minutes. It’s not smart enough to know that you are sat in the car and are listening to the radio. (Well, it knows because of the seat sensor but no one has programmed the logic to leave the radio on.)

Thanks for your prompt response BossBob  MY 09 GS manual in Lago Grey, Wood Co arm rest and side bumper strips - now sold.

MY 15 SD4 SE Auto Orkney Grey with colour coded Bumper Door Mouldings

As said above, it's to stop the battery discharging below a level that would stop you starting the car.

I was getting this warning when I first bought the car, did a check on the battery and charging circuit, which all checked out.

Decided to change it anyway as I didn't know its history. Not had the warning since and that was four years ago.

(The old one is still in use, if we go camping without a hook up, it does a load of LED lights inside the tents.)