with plabook in standby it will charge fairly fast, if using it the battery will drain slightly

you need a high amperage car charger and RIM does make one and a few after market places do make them as well. you need about 2 amps to really get the charge going and most car chargers supply .5 to .7 amps. I have one that does 1 amp and the phone charges quick and playbook with use will charge slowly.