Electrics installation

I have been working on the development of the electrics for Arpex. There is not going to be much electrics there, I keep telling myself, but in the end, you need the basics: Navigation lights, bilge pump, internal illumination, a 12V power plug (for whatever), and while were at it, a sound system. 

I'm still in doubt about the position for the battery. I have some concerns whether it will affect the compass, which is located only about 60-70 cm from it... As far as I know, batteries and compasses are not a thing that goes together well.