If you already have a car charger with a USB female end, an elegant solution is to search on ebay for USB Charger For Nokia N76 N80 N81 N82 N95 8GB CA-100
USB male end to N810 power male end. Plus use it to charge with any USB source.
I found one for US $1.56 with free shipping from HK
USB male end to N810 power male end. Plus use it to charge with any USB source.
I found one for US $1.56 with free shipping from HK