Switch for Hard-Wired Compressor

[Spilsy Avid PP Poster! Find all posts View Profile Close Spilsy]

Howdy all,

Im thinking of hard wiring my Thumper Compressor into my fuse block in the back of the car.
Id like to just use a switch in line (either +ve or -ve) rather than a relay.

Is this possible? - My understanding is that a lot of switches will not handle the bigger load? But are there any that I can install in the back of the prado which will handle the load?

Any help/advice is appreciated.

Cheers!

[Guest Close Guest]

Jaycar has a 30A switch, the highest current rating I could find. It can handle the TJM compressor. Not sure what the current draw is on the Thumper. Best to use a relay.

http://www.jaycar.com.au/Electromech...witch/p/SK0955

[Spilsy Avid PP Poster! Find all posts View Profile Close Spilsy]

For the Thumper:

Maximum voltage: 13.8V
Maximum amp draw: 45A

I'd need a switch that will handle 45A if I were to forgo the relay?

[Guest Close Guest]

Yes, to be safe.
Narva 60078BL
http://www.narva.com.au/products/browse/heavy-duty-2
http://www.narva.com.au/products/det...s-popup-layout

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Does it already have a relay, if so a switch rated at 1A or above will do?

If no relay, then just add one.

[Spilsy Avid PP Poster! Find all posts View Profile Close Spilsy]

If I am to use a relay, can anyone give me a brief explanation of how I'd wire it all up?

Battery - Fuse Block - Relay/Switch - Compressor

Thanks.

[Fred63 Advanced Member Find all posts View Profile Close Fred63]

this is a basic relay circuit
Substitute the light for your compressor and size the fuse to suit the compressor.
the on off switch can go in the dash

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

The switch triggers the relay so fused power to the switch then from the switch (normally open) to terminal 86. Connect terminal 85 to earth or negative. Fused main power supply (50A) to terminal 30 and then connect terminal 87 to the positive side of the compressor. Earth the compressor negative. Size of cable will depend a lot on the length of the cables. Redarc site has a good guide to cable sizes for current draw. I suggest a maxi fuse rather than a normal automotive fuse.

Sometimes the switch will have another terminal to illuminate the switch when the lights are on, run this from other switches light supply. The trigger wire doesn't need to be very large because it is only running an amp or so but the compressor wiring needs to be large enough to handle the current with minimal voltage drop. Probably 6mm2 or so.

I had a Bluetongue compressor in my 120 and the numb nuts who did the suspension and snorkel offed to wire my compressor. I didn't check their work and only later when I changed compressors did I find they wired directly through a Narva 30A switch using 4mm2 wire. I was lucky not to burn the Prado to the ground! I still have the twisted mess that was the wiring in my study.

Make sense?

[Spilsy Avid PP Poster! Find all posts View Profile Close Spilsy]

So, what's been explained is what I had in mind - I think Im learning....
Will need to use 2 supplies from my fuse block, one for the switch and one for the relay/compressor.
Distances will be minimal - fuse block is just behind 2nd row of seats, compressor will be near rear door somewhere.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

If you don't need an on indicator light you can, an easier way is to run one power run to one of the contacts ie 30/51 on the diagram above, with a small jumper across to terminal
85. You now have positive to one of the switching contacts and positive connected to one side of the relay coil, ie 85 goes to the switch. You then only need to supply an earth to the other side of the switch which saves you running battery to it. from 85 to the switch doesn't need to be fused as only a small amount of current can flow in that part of the circuit.

A relay is an electromechanical switch, it has two or more large contacts to
switch large currents. The contacts are closed by apply a small current to
the relays coil which pulls in an armature which operates the contact assembly.

[Fred63 Advanced Member Find all posts View Profile Close Fred63]

If you don't need an on indicator light you can, an easier way is to run one power run to one of the contacts ie 30/51 on the diagram above, with a small jumper across to terminal
85. You now have positive to one of the switching contacts and positive connected to one side of the relay coil, ie 85 goes to the switch. You then only need to supply an earth to the other side of the switch which saves you running battery to it. from 85 to the switch doesn't need to be fused as only a small amount of current can flow in that part of the circuit.

A relay is an electromechanical switch, it has two or more large contacts to
switch large currents. The contacts are closed by apply a small current to
the relays coil which pulls in an armature which operates the contact assembly.

[ATTACH=CONFIG]22152[/ATTACH]

Leigh we could open a can of worms here and add a basic electrical circuits thread to help people out.
I am sure we all have tips and tricks to help others out.

also different opinions on the best solution.

[Spilsy Avid PP Poster! Find all posts View Profile Close Spilsy]

If you don't need an on indicator light you can, an easier way is to run one power run to one of the contacts ie 30/51 on the diagram above, with a small jumper across to terminal
85. You now have positive to one of the switching contacts and positive connected to one side of the relay coil, ie 85 goes to the switch. You then only need to supply an earth to the other side of the switch which saves you running battery to it. from 85 to the switch doesn't need to be fused as only a small amount of current can flow in that part of the circuit.

A relay is an electromechanical switch, it has two or more large contacts to
switch large currents. The contacts are closed by apply a small current to
the relays coil which pulls in an armature which operates the contact assembly.

[ATTACH=CONFIG]22152[/ATTACH]

NOt a bad idea actually...I'll look into that. Save a fuse!

Leigh we could open a can of worms here and add a basic electrical circuits thread to help people out.
I am sure we all have tips and tricks to help others out.

also different opinions on the best solution.

Also not a shabby idea. I'm sure there's a few on here that a) know lots about simple car electrics that could share a multitude of simple diagrams and b) no not a lot (myself included) and would love a bank of diagrams and tips to browse through.

A single location for - Dual Battery Wiring, Driving Light Wiring, Compressor Wiring, Anderson Plug Wiring, Brake Controller Wiring, Reverse Light Wiring, UHF wiring etc...

[120D4D Avid PP Poster! Find all posts View Profile Close 120D4D]

NOt a bad idea actually...I'll look into that. Save a fuse!



Also not a shabby idea. I'm sure there's a few on here that a) know lots about simple car electrics that could share a multitude of simple diagrams and b) no not a lot (myself included) and would love a bank of diagrams and tips to browse through.

A single location for - Dual Battery Wiring, Driving Light Wiring, Compressor Wiring, Anderson Plug Wiring, Brake Controller Wiring, Reverse Light Wiring, UHF wiring etc...

Try this website Splisy, it will keep you busy for hours:

http://www.the12volt.com/info/diagrams.asp