Mud-club

Vehicle & Technical => Discovery => Topic started by: Big Rich on January 31, 2005, 17:56:23

Title: Can I use a spair switch?
Post by: Big Rich on January 31, 2005, 17:56:23

Will the switch on the dash (Disco 200 Tdi 1991) say the rear heater or wiper type switch be okay to use for 6 Hella FF50 spot lamps? 8)

Rich

Title: Can I use a spair switch?
Post by: muddyweb on January 31, 2005, 18:14:36

With 6 lamps, you will want to put them through a couple of relays.

6 x 55W Lamps is around 27 Amps.  

The switch will be OK to fire a relay though, yes.

Title: Can I use a spair switch?
Post by: Hightower on January 31, 2005, 19:59:33

I used one switch to control the two relays that my 4 FF50's are connected to and that was fine.
Then I changed my mind and fitted a switch per pair.  I'll probably change back in a while  :?

Title: Can I use a spair switch?
Post by: Big Rich on January 31, 2005, 20:35:04

This may be a stupid question but.....
 :oops: (I'm not to knowlagable about electrics.)  :oops:

Is there a speciffic relay or relays I need to get?

If so what are ther and where would you suggest I go?

Rich

Title: Can I use a spair switch?
Post by: muddyweb on January 31, 2005, 20:50:16

<cue my fantastic diagram>

Normal Automotive relays are what you want.  4 terminal.

http://www.muddyweb.com/downloads/aux_lights.JPG

Halfords, Local Auto Shop, Vehicle Wiring Products.... they all do them

Title: Can I use a spair switch?
Post by: Big Rich on January 31, 2005, 21:06:04

Thanks Tim.

Title: Can I use a spair switch?
Post by: Range Rover Blues on February 01, 2005, 00:26:53

Quote from: "muddyweb"

<cue my fantastic diagram>

Normal Automotive relays are what you want.  4 terminal.

http://www.muddyweb.com/downloads/aux_lights.JPG

Halfords, Local Auto Shop, Vehicle Wiring Products.... they all do them

Getting your money's worth from that diagram.

Title: Can I use a spair switch?
Post by: muddyweb on February 01, 2005, 08:32:58

What can I say.... true art is immortal.

Title: Can I use a spair switch?
Post by: Wanderer on February 01, 2005, 13:23:31

I've just had the Tate on the phone Tim.

They weren't after the beer mat diagram. They want Daz's old boot floor .
 :lol:
Ed

Title: Can I use a spair switch?
Post by: muddyweb on February 01, 2005, 13:35:45

I'll sweep it up, put it in an envelope and send it to them :-)

Title: Can I use a spair switch?
Post by: Big Rich on February 01, 2005, 15:35:46

Hi

Is this the sort of relay you mean Tim?

Designed with automotive applications in mind, this high power relay is capable of switching loads up to 40A at 12V. Suitable for controlling spotlights, heater systems, wiper motors, compressor driven air horns, tailgate lifts etc. Electrical contact is made with push on 635mm (1/4in.) blade conne...

Or is it too big? What's the best cable to use as well?

Thanks.

Rich

Title: Can I use a spair switch?
Post by: Wanderer on February 01, 2005, 15:39:00

That'll do you Rich.
All you are after is protecting the wiring and switch when you switch the lights on.
The relay handles the high current without it going through the switch itself and can also cope with any arcing that may take place (or stop it happening) which would burn out your standard switch.

Ed

Title: Can I use a spair switch?
Post by: Wanderer on February 01, 2005, 15:39:58

Big is usually better by the way. Unless you star talking 600 amp relays :)

Ed

Title: Can I use a spair switch?
Post by: Big Rich on February 01, 2005, 15:45:24

a.... So that could be why if I use my air horns for more than a min it blows the fuse cus we didn't use the relay's. Thought my mate at the time knew all about it.
 :?
Rich

Title: Can I use a spair switch?
Post by: Wanderer on February 01, 2005, 15:52:11

The basic idea behind a relay is that you can have it near the battery or the "appliance" so as short a run of cable as possible is possible. Which keeps down volt drop.
Also you can run thinner wires and/or less capable switches. All of the work is done at the relay end. All the switches and wiring for the switch has to do is switch the relay. This needs minimal current.

Early Disco wiring (don't know about later stuff) just isn't capable of running much more than sandard lamps. So even higher rating bulbs in the headlights should have relays used to protect the wiring harness and the lighting switch.

Without a relay you will draw all of the current across the contaacts of the switch and soon wear it out.

Ed.