Well-Known Member
Jan 21, 2010
Like many folks I have been scratching my head (and searching the forums) for the reason my D3 did not seem to charge when plugged into the built-in USB charging connection in my car.

After installing Battery Spy (great app) I was able to figure out that the USB DEBUGGING setting controlled the charging condition when plugged into the car.

It took one D1 and two D3s all running Battery spy for me to finally find the right condition that isolated the problem.

On the D1, it didn't matter. USB Debugging on or off - it charges.

On the D3, it does matter. USB Debugging on - will not charge on the car. It initially says charging for a second then switches to discharging.

With USB Debugging off - it charges.

All this is with the D3 USB setting set to charge only.

I hope this helps some other folks too. I know I was getting a little frustrated at using the D3 in the car and even though it was plugged in for charging, my battery just kept dropping.

Make sure USB debugging is set to OFF while in the car. :)
now this is a built in USB port youre talkinga bout, yes?

great work on the findings and thanks for sharing!
Many newer cars (including mine) have a built in USB socket. In the case of my car (Lexus RX450H) they advertise that the USB connection also works with an iPod/iPad to play music. So far the Android devices have not figured that out yet, but I am sure it's only a matter of time.

The dealer I talked to initially said it might be the USB cable since they had many cable problems (who knows how "many" that might be) but after swapping a couple of those, I determined that the original cable was fine.

Since we have two D3s (BOGO) and mine is now rooted but my wife's is not, and I still have the old D1, I was able to put together enough test configurations to see what the culprit was, and Battery Spy told me if it was really charging or not.

The D1 is running 2.3.4 (GPA16 from Peter Alfonso) so it doesn't look like an Android system issue, but maybe the kernel (very different versions between the D1 and D3) or something in the hardware itself.

It's a minor hassle to turn USB debugging off when I want to charge the D3 in the car and then on when I get out, but I can live with that.
I have 2.3.4 installed on the D1 but I really don't use it. The phone is not active with VZN and I can only use it as a hand held computer with a WIFI connection. I am keeping it around as an emergency backup in case I smash (or brick) my D3.

I probably should sell or donate it.
depending on how much you want for it, or if youre willing to donate it, i know a few people who would love to have it.

My wife for one...she's using a blackberry curve 3830 or something haha.

as i also said i know a few other people that are in need of a phone.