this is bad, while using 4G connection to download the phone eat up more power than the wall charger can provide. I had a half charge on my battery, connected the phone to the wall charger and started downloading the US Maps for the Navigon Mobile Navigator app(around 2 gigs). The phone indicated that it would take about and hour to complete so I just left it downloading. later on I went back to the phone to check the download status and battery had been fully drained and powered down. The phone was really hot as well, hot enough that I didn't really even want to hold it in fear of it burning my hand. with the battery drained, I could only get it to start charging back up by either leaving the phone off and charging or on with airplane mode on.