Nearly 2 yr old golf r, 66 reg, had it from new, done 21k miles. 2-3 weeks ago I received a 12v battery low warning on dash. At the time I was sat in a car park waiting for the wife to come out of a shop, radio on, phone plugged in to charger for about 30 minutes. I unplugged phone and started the car no problem. I put it down to my phone being plugged in and forgot about it.
Had the same today, although this time the radio was on, no phone plugged in, waiting in car (for wife again, recurring theme this!) for about 20 minutes. Dash alert said turn off infotainment, I tried to start the car, not enough juice to get it going. Waited a few minutes, tried again and thankfully it started. I promptly switched off engine stop/start to avoid any embarrassment whilst driving home! I had two hours of motorway driving on Saturday, I would have thought it would have been well and truly fully charged after that (with phone plugged in and radio on however...).
I have been driving less miles over the last 12 months, I used to drive in to the office every week day, 15 miles on the motorway each way, this is now once a week. To be honest I do tend to drive around in eco mode (yes in a golf r lol), so it does coast a bit, I assume when it is coasting it isn't charging the battery. Weekends generally involve some longer driving, but there will be a fair few short drives nearly every day.
Car is due in for a service later this month - Is this kind of thing expected, or is my battery duff? With it getting colder and all, I'm keen to fix whatever may be wrong.