pressure switch and relay setup

[guzzla]

hey guys spent the last 1/2 hr searching for info but no piccys. ive got a 12v 35a air compressor and will be setting it up to run through a tank and switched from the cab.

my question is could someone please detail a wiring diagram showing the correct way to wire up the compressor, relay, switch and pressure switch. keep electrical symbols to a minimum as i will only have to ask what they are please.

i would like to draw power direct from the 2nd battery.

this would be good for the bible too.

thanks heaps in advance people.

regards,
nathan

[Cossie]

The relay is drawn bigger than the compressor so you can see all the pin numbers (but check on the relay you intend to use as they can vary!) you will need a 40amp relay.

You will also need a fuse in the line between the battery and the relay, the cable used here should be 6mm, the fuse size depends on the compressor obviously - 35A seems quite high though, most compressors have a 25 or 30 amp fuse.

the small red cable that goes to the switch, then the pressure switch, then the relay can be small (4mm is ample), same for the small earth wire from pin 85.

Any reason you want to run it off your 2nd battery? most people will only use the compressor with the engine running as it can draw a lot of power for a long period of time, in which case it may as well go off your main.

[guzzla]

cossie your a big help mate youve gone to alot of effort. thanks heaps.

i will be running it off the 2nd battery as i alredy have a terminal block from that battery in the glovebox. 35a is alot but its a big compressor.

thanks again.

[Cossie]

No worries dude. Just make sure you remember the fuse (I forgot to put it on the drawing until I had already saved and uploaded it!)

and make sure the wiring to the terminal block is adequate for all the accessories running off it. The compressor can draw a lot of power for a long time and will melt wires if not big enough.

any queries just give us a shout.