C30 2012 powercable to battery
 

Hi! I recently got my first car, a volvo r-design c30 (2012) and i have been wanting to install a subwoofer, as i had a powered one laying around i just bought the neccessary wiring for it and a high-low convertet as i will be connecting it through the rear speaker.
But i have a big problem in figuring out where to stick my power cable through from the interior to the battery, i’ve figured where the firewall is in the engineroom of the car but i cant seem to find it through the interior. Does anyone have any experience with this?