Fuses for headlights

[32valves]

I've been meaning to re-wire the headlights on the Sprint for ages and finally got round to it today. I've used the existing supply from the column switches to power the relay coils (1 for dip, 1 for main) and run a new feed from the battery +ve through the relays and into the supply wiring for the dip and main circuits. I intend to fit some in-line fuses in the relay-to-headlamp part of the circuit. Is this the best place for them ?

Fitted some nice, new headlamp bowls and extra bright halogen bulbs too.

[Nick Jones]

If you are going fuse headlights, fuse the left and right separately to minimise the chance of being left in the dark by one blowing bulb popping the fuse......

Nick

[Dicky Blighter]

I used fused relays - but always best to have fuse as far 'up-stream' as possible (i.e. on feed to relay) and as close to power source as possible, that way any problems will always blow fuse instead of a component.  
In this case if for any reason the relay caused a problem your wiring to the relay from battery would not be protected and would result in lots of smoke and melted wiring (or burnt out car!)

[CRAJ]

Dicky_Blighter wrote:

I used fused relays - but always best to have fuse as far 'up-stream' as possible (i.e. on feed to relay) and as close to power source as possible, that way any problems will always blow fuse instead of a component.  
In this case if for any reason the relay caused a problem your wiring to the relay from battery would not be protected and would result in lots of smoke and melted wiring (or burnt out car!)

I used fused relays on both of our cars, very neat solution and all in one place.

Colin.

[James]

Ideally you want a big fuse to cover the all the lights close to the battery and then smaller fuses near the relays?

Seems like the best solution.

[piman]

Hello James,

"Ideally you want a big fuse to cover the all the lights close to the battery and then smaller fuses near the relays?"

That is ideal, and a Nick mentioned you want to have the least disruption, so the primary fuse needs to be sized large enough that it doesn't blow if a lamp circuit earths, only the lamp fuse should blow . This is called discrimination in electrical engineering terms, main fuse at say 2 times total load and lamp fuses at 1.5 times lamp load.

Alec

[32valves]

Thanks for all the replies. The lights are 2x 60W dip and 4x 55W main. I made up a box with two 40 amp relays and a small blade fuse box. I've provided a separate +ve feed from the battery for the dip and main circuits. Each runs through a 30 amp fuse to one of the relays. The return to the lights runs through a 15 amp fuse, one for each of the three light circuits (1 dip and 2 main). I've also used tell-tale fuses throughout to aid fault diagnosis. Everything works perfectly apart from a couple of connections that need tightening. So, just a final bit of tidying to do with the wiring then some adjustment of the head lamp beams and it's job done  ;)

[partsaver]

I'm in the process of wiring up the 1500HL with a new fuse and relay box,the sidelights are fused as one but the headdlights will be seperatly fused and relayed so unless there is total blackout there will be at least one working drivers side light.

[Velocita Rosso]

Carl....get rid of the candles an slap some 100w lamps in for the RBRR.... when lit you`d see Nigel at Sugar Loaf from Chester ;D
There was a a chap who chopped me up up on the M6 in 2010 and nearly took me out ,I slapped all six ( 520 amps ??) ) lamps on and I think I singed the back of his neck.... ;D
He moved out the way though....

[32valves]

;D ;D ;D

Well Mike, I'd definitely have to upgrade part of the loom to do that so a job for another day. The hard work is done though. For now I'm using Osram Nightbreakers throughout. These, and the new head lamps, have resulted in a big improvement in illumination (bearing in mind that I had standard halogens already).

Judging by other threads about fitting improved lighting I reckon it will be possible to follow the RBRR progress from space  ;D

[drofgum]

michael_charlton wrote:

Carl....get rid of the candles an slap some 100w lamps in for the RBRR.... when lit you`d see Nigel at Sugar Loaf from Chester ;D
There was a a chap who chopped me up up on the M6 in 2010 and nearly took me out ,I slapped all six ( 520 amps ??) ) lamps on and I think I singed the back of his neck.... ;D
He moved out the way though....

520 amps!!! What do you use to switch the headlamps? Starter relays? ;D
                                                                           Cheers,
                                                                           Paul

[Velocita Rosso]

1317 wrote:

520 amps!!! What do you use to switch the headlamps? Starter relays? ;D
                                                                           Cheers,
                                                                           Paul

Oops..... 520 watt.....(dizzy)

[piman]

Hello VR,

that's 43 amps at a nominal 12volts, and worse about 3/4 of a horse power you're losing there.

Alec

[James]

I had 600W on one RBRR :)

4 x 100W standard lights and an additional 2 x 100W spots.

I think.

Hmmmm feeling I am missing out on all this prep now.

[Velocita Rosso]

piman wrote:

Hello VR,

that's 43 amps at a nominal 12volts, and worse about 3/4 of a horse power you're losing there.

Alec

Uprated 65 amp alternator .................and another 97 hp to play with ;D

[piman]

Hello V.R.,

have you thought of fitting KERS, that alternator's worth another HP or two.

Alec