On multiple occasions, I had encountered a problem where my Lenovo ThinkPad E430 would not charge its battery when plugged into an AC wall outlet. When I moused over the battery icon in the system tray, I would see the message, “Plugged in, not charging.” This post discusses some responses to that message.
On this particular occasion, I was having an odd variation on the problem. It would not occur when I had the AC adapter plugged into a regular wall outlet, but it would happen when I connected the AC adapter to a DC inverter (designed to be plugged into a cigarette lighter) and connected the inverter to a car battery.
There was, incidentally, another and possibly related oddity. The laptop was capable of running without its battery installed. That is, I could remove the battery, connect the AC adapter, plug it into the wall, and the laptop would run normally. But it would not run reliably if I connected the AC adapter to the DC inverter to the car battery. It would run for a few seconds and then crash. I say this may have been related because I wondered whether irregular AC current, of the type that may have been supplied by a DC inverter, would not only be insufficiently reliable for the laptop, but might also trigger the “plugged in, not charging” problem.
It appeared that, for some people, the “plugged in, not charging” problem was due to imperfect battery installation. That is, you could resolve this problem by just shoving the battery into the laptop more firmly. Since mine was working properly with the AC adapter connected to the wall, I inferred that this was not the explanation in this instance.
Another procedure, recommended by a number of webpages, was to go into Control Panel > Device Manager > Batteries > right-click on Microsoft ACPI-Compliant Control Method Battery > Uninstall. It appeared that this procedure had to be done with the battery removed. The full advice was to precede the Uninstall with a full shutdown before removing the battery, and then follow the Uninstall with another full shutdown before reinserting the battery. The AC adapter would be connected as the very first and last steps, and also in the middle, when doing the Uninstall.
I did that. But then I discovered what the problem seemed to be on this particular occasion. The car battery was completely drained. That is why it would not charge the laptop. Silly to have overlooked the possibility.