I am using my ipod car charger (with USB connection, purchased from ebay) with Desire's micro USB cable. I tried this during a 3 hr trip. I was using the Desire for navigation (Google SATNAV) during the trip. So, GPS was turned on and the screen was on as well. What I observed was, even though the phone was charging (using the car charger), the battery was actually loosing the life. Meaning, GPS and screen was consuming battery faster than the car charger was able to charge it. While charging, the status of batter was displayed as "Charging (AC)". I am trying to understand 1. if this was because of not using proper car charger, 2. or if something is wrong with my battery, 3. or if that's how Desire battery behaves in which case it doesn't make it suitable for a Tomtom replacement. Any thoughts?