I dont have the same interface - but I am using HPTuners on my carpc for tuning/guages/diagnostics and have found that if the car sits for about 4 days without starting the HPTuners interface will pull the battery down - course then I plan on getting an Optima someday when the current battery dies. I ended up putting a switch in the OBDII power line on my car just in case it is going to sit for awhile - no problem for me during the warmer months with the car sitting much though
