Android Tablet as Car PC

Step 6: Running Wire Through Holes in Metal

Also, to get the power from your battery to the amplifier you will probably have to drill a hole in your firewall of your car.  You may be able to poke the wire through a hole already there, but it is quite easy to drill a hole in the firewall.  Here or anywhere you run wire through a hole in metal use a rubber grommet.  This will prevent the jacket of the wire from being worn down from rubbing on the metal.  I have a small hole in the passengers side footwell.  The power cable for the amplifier runs through the hole, directly under the carpet, up through a hole in the carpet underneath the seat to the amplifier.