Join Date: Jul 2005
Nominated 0 Times in 7 Posts
TOTW/F/M Award(s): 8
Thanked 95 Times in 64 Posts
I would expect either the phone or the charger (and probably both) to have discharge protection built in, but if neither does, then it's possible that the phone battery would end up powering the other devices on the ignition live circuit, and that would kill off the phone battery pretty quickly.
Try disconnecting the charger from the car, just plugging it into the (already charged) phone and see if you can get a voltage reading across the terminals on the charger's lighter plug with a multimeter. If you see a reading, then it proves the point.
There are other possibilities, even if you don't get a reading. There may be something in the charger that's discharging the battery internally when there's no power from the car, or the very fact that the charger's plugged in might mean that the phone is considering itself to be on external power, and preventing it from going into a power saving mode.
Currently in Horatio's garage:
2010 Laguna III Initiale.