Unfortunately, this car charger is too weak to charge the battery 920 of my Nokia Lumia with ongoing navigation. The charger does not even manage to hold constant the battery charge in this situation. If you're looking for just a charger to charge his inactive smartphone in the car, then you can take this Hama charger, it is solid. Allen who use their Lumia 920 as a navigation device, I can not recommend this charger. This is true, unfortunately, as I have read in other reviews, on the other most car chargers to.
My advice: Look at the car charger anchor 18W / 3600mA with festinstalliertem Micro-USB cable (see my review it). The unit of anchor loads to my Lumia 920 battery while playing a full navigation (!).