Hard wiring an air compressor

[taslucas]

Hi, I have an air compressor with alligator clips. I have an idea to fit it in the car, remove the clips and hardwire in with a switch. Is there any problems in doing this? Would it be a good idea to fit a fuse?

[97_gq_lwb]

Just put a fuse in line up near the battery it would be fine.

[BillsGU]

If it is a decent compressor then it will draw quite a few amps. You should use heavy duty cable (6mm or there abouts) and a relay (because at high currents most switches will burn out contacts). Also - compressors get hot when they are used for a while and don't really like being placed under the bonnet with an already hot engine. For portability, heat and keeping grease and muck off it - I keep mine in a plastic case in the rear drawers.

[97_gq_lwb]

Why make it more complicated.
I would assume the wiring already on the compressor would be sufficient.
And why complicate things with a relay just run it off the batttery the same as it does now but fit a fuse .

[MudRunnerTD]

Why make it more complicated.
I would assume the wiring already on the compressor would be sufficient.
And why complicate things with a relay just run it off the batttery the same as it does now but fit a fuse .

Because the alligator clips are the Switch ;) You will absolutely need a Relay in the switching circuit. A big relay! 40 to 70 amps if you can. depending on where you are mounting it run the biggest cable you can to it. The wire currently connected to the compressor will be fairly small and short. Current drop on a 12v circuit will be substantial. Current drop will mean a compressor that is running slower than designed and therefore output will be reduced and airup times increase.

If your running it to the back then consider running a big wire to the back and putting in a fuse box there. that way you can run your compressor from it and also run a 2nd circuit for a fridge from your supply at the rear.

Make sure your compressor is ventilated as they do get hot.

[97_gq_lwb]

I have 3 different compressors here and they all have a built in switch.

[taslucas]

Thanks guys,
Im planing on putting it in the rear side panel. Good idea to have a fuse box in the rear so that I can add a fridge etc in the future. Thanks again.

[BillsGU]

Why make it more complicated.
I would assume the wiring already on the compressor would be sufficient.
And why complicate things with a relay just run it off the batttery the same as it does now but fit a fuse .

The reason is most people place it to the rear of the vehicle and have to extend the cable. More cable - more voltage drop - cable gets hotter - so you need cable that is a larger diameter to reduce these losses. Next time you have pumped up 4 tyres, feel the cable and the battery clamps.