18 replies to this topic

[samsfern]

im going to be fitting my spotlights back on tommorow, due to bodgy wiring by previous owner, i have got to rewire them, ive upgraded the bulbs from 55w to 130w, and have 4 spot/fog lights. Will i need to wire them up with 2 relays? Im going to be wiring them up so they come on with fullbeam.

Also whats the difference between spots and fogs and how do i tell the difference?

Many thanks again, sam

[Midas Mk1]

Im not sure about the relays, but Spots have a clear lense, fogs have a patterned lense

[WiredbyWilson]

i would be more concerned that you alternator may not cope with 4 130w bulbs coming on along with everything else!

why did you upgrade to bulbs out of interest as I don't think 130w is road legal??

when i wired mine in used a relay per 2 spots - but only 2 come on with main beam, the other 2 are on a side light fed switch.

also remember you are fusing the wire to the spots, not the bulbs!! so make sure the wiring is up to the job.

[samsfern]

well two of the standard 55w have blown, probably where i touched them, so why not buy better? I upgrade to two 130w from 55ws on my old minis spots, made a huge difference. And yes they are for offroad use only, the old boy at the till reminded me as well, lol

[WiredbyWilson]

Im just saying with bulbs well in excess of twice the current will the electrics cope with the extra load? I wasn't questioning why you bought them, more on the side of potentially melting wires / terminals / fuses as a result.

There is no reason not to use them, but make sure you upgrade the wiring and alternator so that they can cope.

But in answer to you question, IMHO I would use 2 relays.

[Dan]

You will have to use 2 relays anyway because fogs and spots have different switching requirements, they must be on at different times. As far as I remember there is no output limit for auxiliary main beam lamps (spots or driving lamps) because they must be switched off if they might dazzle someone anyway but if you try to drive about with 2 130 watt fogs switched on all the time as is the current trend amongst Chavs, Audi drivers and other imbeciles you are almost certain to get pulled. Each lamp will now be pulling 11 Amps, so each pair will draw 22. A 30 amp relay on each pair of lamps will be perfect and suitable fusing (which allows for at least 25 Amps CONTINUOUS current, make sure you know what that means) providing the cable is up to it. Remember the earth carries just as much current as the live.

[The Matt]

P=VI

Where P = power(in Watts), V = Volts and I = current in Amps

So, you're running a P (power) of 130x4, which is 520W total power.

if P = VI, then P/V = I

therefore, 520/12V = 43.333Amps total.

Basically, if your relays can't cope with the above current, then they'll need splitting. I don't know what your relays are rated at. But check that out. You also do need to check that the wiring is up to it and that the wiring is fused correctly.

520W is a LOT of lighting though!

[The Matt]

Dan has quicker fingers than me, dammit!

[samsfern]

when yot say uprate the alternator what to? I think mine may have already been played with, it dont look too old, and the previous owner told me its a 70amp one or something along those lines, as he was running some serious ICE he told me., thanks

they will be wired up so that they will only come on with full beam, but go through a seperate switch as well, but still only come on on full beam.

Edited by samsernie, 15 March 2010 - 07:53 PM.

[The Matt]

Well, you've got to consider how much load you're going to be using.

A 70A alternator is a good start, but if you drive around with headlights on, tail lights, radio, 4 spotlights and your heater going, your battery aint going to be staying charged for too long, I suspect!

[Dan]

they will be wired up so that they will only come on with full beam, but go through a seperate switch as well, but still only come on on full beam

That's fine for the spots but fogs must not be switched on unless visibility is seriously reduced, you will get into legal problems and might not pass an MOT if they come on at the wrong time. High power fog lamps like that are pointless, they will just dazzle you in fog. More so than the standard dipped beam will.

[samsfern]

im not intending to use them as foglights, theyll just be main beam driving lamps, and yes your right, high power lights like that do make driving in the dark and fog terrible, and dip beam is better, lol

[Neil7744]

matt is right for the amount of current being consumed by those uber lights. Bear in mind how you feed these and where you decide to split the wiring.

When i did mine, main beam 12v to my headlights was simply wired into the spot relay, but then the 12v hardcore feed for the spots was taken off the live feed at the fusebox on the bulkhead. If you wire a similar setup id be careful on pulling an additional 40 odd amps through the current wiring loom.


Sounds like a mental idea though. I like! Mine were proper bright and only had 55 watts in lol. You may also want to consider (as mentioned) a bigger alternator, but also a bigger Ah rated battery (if you dont have one).

[samsfern]

the battery could well be already uprated, im going to take the lives for the relays off the starter, where the battery lead connects to it. have the old loom (bodgy thanks to previous owner) on the kitchen table and im making a new one, with some pretty serious looking wires, lol

[Neil7744]

thats the route i would take.

good luck