Headlight relays

[carmadmike]

Hi

I am trying to fit headlight relays to my dolomite sprint. Does anyone know what size cable should I use? Also I was thinking 2 X 40amp 5 pin relays for for the main beam circuit as I can run a separate wire to each bulb and another 40amp 5 pin relay for the dipped headlights an again one wire to each bulb. Any advice much appreciated.

Thanks Mike 

[Howard]

50w bulb will draw less than 5A so a 40A relay is an overkill.

Hope that helps

Howard

[carmadmike]

Hi

Thanks for the reply I've seen some 30amp fused relays so will go with 2 of those one for mains and one for dipped headlights. Does anyone have any idea on wire size I thought 2mm. Electrics aren't my strong point so any advice.

Thanks Mike

 

[Clive]

I recently fitted relays to my 1850. 

I cut into the loom behind/under the dash. And use a pair of relays, one for dipped, one for main. I used a single feed wire to the 2 relays, 33A cable and that was protected by a single 30A continious rated fuse close to the battery so all the wire is protected (fused relays only protect the wiring after the relay)

As to wire size, auto wiring is often sold by current. But for thin wall cable (beware, thick walled will be different) 2mm is 25A, so adequate for the 4x main beams. But I would probably overspec to 3mm (33A)  

1mm is 17A, so if you go for 3 relays, that would be ideal. As long as you feed each relay individually. 15A fuses in the 3 relays. 

 

[carmadmike]

Hi Clive

Thanks for the reply it has been very helpful. I will probably go with 3 relays (2 for main beam 1 for headlight) with 3 separate 2mm thin wall to feed them fitted with 15amp fuses. Then use 2mm, 25amp thinwall blue/White, blue/red to keep the colour's original. I'll also run new earth in 2mm thinwall as well. Does this sound ok.

Mike 

[thescrapman]

I have gone with the cheapo Chinese relay setups off EBay. Work fine, just protect relays from water. 

Dead easy to install

[Clive]

3 hours ago, carmadmike said:

Hi Clive

Thanks for the reply it has been very helpful. I will probably go with 3 relays (2 for main beam 1 for headlight) with 3 separate 2mm thin wall to feed them fitted with 15amp fuses. Then use 2mm, 25amp thinwall blue/White, blue/red to keep the colour's original. I'll also run new earth in 2mm thinwall as well. Does this sound ok.

Mike 

The relay earth can be tiny, the current is so small. Otherwise, yes, sounds good to me.

 

43 minutes ago, thescrapman said:

I have gone with the cheapo Chinese relay setups off EBay. Work fine, just protect relays from water. 

Dead easy to install

I used them, but boy can they rust. The 2nd set I stprayed with some wax protection spray, and that certainly helped.

[carmadmike]

Thanks for the help can now put my order in and be another step closer the getting the dolomite sprint on the road.

Mike