What gauge wire and what amperage fuse did you use to wire it up? How long is your wire run? And what's the max amperage your compressor draws?

 

I dont have onboard air but have been looking into it myself, From my research most compressors draw less than 20 amps max, so for fusing id say 20 amps, wire guage really depends on where you are going to place the compressor, I have 2 extra batteries in my toolbox so mine will be 10awg to the compressor under the bed (where spare used to be).