THE BUDDAH

New Member

• Jul 26, 2014

• #1

Hello,

Im looking to run some electrical extras on me disco1 powered through a fusebox attatched to my secondary battery.

I have had a dash plate made up with two volt meters some switches and two 12v cigerette lighter sockets.

This guy tells me that i should not connect anything to switches unless i use a relay.

First of all id like to know is this correct?

If so what type of relay do i need?

Where does the relay go?

Do I need a relay for every item i connect to the fusebox?

Thank you for putting me straight here cos as you can tell i aint gota clue...lol

 

Last edited: Jul 26, 2014

SmileySteve

Well-Known Member

• Jul 26, 2014

• #2

All depends on what items you are trying to power up.
Basically many commercial auto switches are only good for a few amps, so if you wanted to power something that takes 5 amps plus, then yes use a relay.
The switch is used just to power / switch on the relay that then connects the main load.

 

SmileySteve

Well-Known Member

• Jul 26, 2014

• #3

Also position of the relay (if needed).
Its better to run long wires that carry less current, so the relay is better mounted nearer the load or the battery with the longest cable run being form the switch.
Just a rule of thumb, as heavy cable is more expensive than lighter cable!

 

THE BUDDAH

New Member

• Jul 26, 2014

• #4

Cheers Smileysteve,

1 switch for tyre air compressor
1 " " roof lights x 4
1 " " cabin led light
2 " " volt meter 1 per battery
2 " " 2 x cigerette lighters
1 " " inverter

Does this mean i need 8 relays?

 

SmileySteve

Well-Known Member

• Jul 26, 2014

• #5

Nope, just need relays for anything over and above the rated current of the switch.

LED lights are low power, meters take nearly zero power, CIG lighters normally 8-10 amp so use switched breaker or relay (unless you are direct wiring them and not using a switch, just make sure they are fused according to their rating)
So the tyre compressor if switched would benefit a relay, and not sure what size inverter you are fitting but they can draw a fair bit of current

 

THE BUDDAH

New Member

• Jul 26, 2014

• #6

The switches i bought are 12v 20 amps.

from here 12 V LED Switch