Hi.
i need to run a battery cable room the battery to the interior, where would be the most accessible place to go through the firewall ?
I was looking at going through the channel where all the lovely water flows into the footwell .
For a solar panel I went out of the engine compartment straight across the door seal, at the level of the bottom of the window, and inside. No holes needed and it didn't leak. IIRC I used about 3mm. wire.