I purchased the Vz car dock charger thinking how cool this product would be for my new Droid X. I am beginning to think that using it can be dangerous, at least for the battery. I have also been reading thru the different posts concerning the car dock and battery charge problems. I am no expert on this subject, but I have a theory on the battery charging problems with the car dock. Lithium-ion batterys have a safety feature, essentially a switch, that shuts off charging if the battery temperature gets too hot or the voltage gets outside of a prescribed safety range. The battery also discharges much more quickly at higher temperatures. I do live in the hot southeast USA. My Droid X has a battery widget which displays the battery health items temperature and voltage. Although I do not know the accuracy of the health display, I do feel that the values vary properly according to the operating conditions. The other day I decided to test the navigation feature on my way home from work. It was around 2:00 pm, and the sun was high in the sky. Within 5 minutes of placing in the charger, the battery charge level dropped from 80% to 70%. The widget displayed the status as "Overheating" and a temperature of 135 degrees F, which is quite high for this battery. I removed the phone from the dock, and found the back very hot. I suspect the sun shining on the dock which transferred this energy/heat to the phone, which also blocks ability to vent the heat, caused the battery to get too hot. Therefore, my guess is the charging stopped to prevent damage to the battery, or worse a fire. I did not look at the voltage display. I also wonder if this could cause a short circuit in one of the battery cells permanently damaging the battery? And yes, I did have my car A/C on full blast, and it was comfortable in my car. Therefore, I plan to return this charging unit, explaining to Vz my concern. If anyone else has a theory on the problem or has a contrary viewpoint, please chime in on this subject. Thanks and have a great day!