Yesterday I needed a jump start because somehow my battery got drained. I have a 2013 Honda CRV with less than 10K miles on it. I drove about two hours to a soccer tournament and between games sat in the car with the key turned to “accessory” mode. The sound system was on, playing music from my daughter’s phone, and my phone was charging, evidenced by the little lightning icon. (That’s an iPhone and an Android plugged in simultaneously, if it matters.)
At one point I looked down and saw that the battery indicator on the phone hadn’t increased at all, so I went to turn the car on so it would charge more effectively. Lo and behold, the battery was completely dead. We couldn’t have been there more than 30 minutes.
I called roadside assistance and the guy who came to give me a jump said yep, it was the fact that the car wasn’t on and we had things plugged in. But I find it hard to believe that two phones could actually drain a car battery. And in any event, if that’s what happened, wouldn’t the phone have actually charged?