uprated headlight loom

[danny_p]

nether, output isn't linear to power consumption  nor is buld life belive it or not !

halogen bulbs have some intresting properties

power consumption is relative to voltage, but

less than rated voltage means filament runs cooler so light output is signifactly reduced and the halogen effect dosent work properly  light output is reduced by about 20% for 1 volt reduction,    life reduced a bit,      go over 1 volt and light output goes up but bulb life roughly halved,   exact valuse depend on bulb constuction,  but they all have quite a narrow optimal operating sweet spot.

and 12v car bulbs arnt ether 12v just to make it more intresting

[leeroy20vt]

nether, output isn't linear to power consumption  nor is buld life belive it or not !

halogen bulbs have some intresting properties

power consumption is relative to voltage, but

less than rated voltage means filament runs cooler so light output is signifactly reduced and the halogen effect dosent work properly  light output is reduced by about 20% for 1 volt reduction,    life reduced a bit,      go over 1 volt and light output goes up but bulb life roughly halved,   exact valuse depend on bulb constuction,  but they all have quite a narrow optimal operating sweet spot.

and 12v car bulbs arnt ether 12v just to make it more intresting

hmmm might have to have a read up on this just to understand 

will the loom handle 100/80 watt bulbs ?? from what i read they will but didnt want to go to ott

[h8v]

"Will the loom handle 100/80 watt bulbs?"

Well, if each side is relayed seperately, then dipped beam is only 80 watts, so that's about 6 amps each side. Each main beam side would be 100w main bulb + 55w inner spot bulb, total 155 watts, about 13 amps. 

If you've relayed each side with decent sized cable, and given that there's not much of a length of cable for each side, then things ought to be fine.

If you have only one relay for dipped, that will still be OK at about 16 amps, but if you've only one relay for all four main beam bulbs, that would be about 26 amps.. pushing things a bit, unless you use a 40amp relay. Relaying each side seperately would be better.

But as I said way back on page one or two of this thread, why not give it a try.  Pop in a 100/80 bulb on one side, switch them on at night and see what it looks like.  You can check the voltage at the bulb to get an idea of whether the cable is being overloaded (the closer the bulb voltage is to the battery voltage the better)

Bulbs from discountcarbulbs.com, £24.99 for ten.  Then bulb life won't matter much!!

Enjoy your night driving.

[h8v]

Re: above post.

Sorry, line four should read 12 amps, not 16 amps.  Timesing bt two is not my strong point!!

[danny_p]

i ran  55/130 w H4 bulbs on my uprated loom and 130w spots not problem,  use 2.5mm cabel for carrying the power to relays and it's no problem.

std loom 80/100 is a bit much if spots are involved as well,  if not it'll cope as in not burn but voltage drop will be a littel more   

[leeroy20vt]

i have 2 relays 1 for each side of the dipped beam with about 2.5mm live wire and about 1.5 earth if that makes any difference i dont have the middle spots either single light grille

so if i got somethink like this as a example http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=270527893298

i sopose i should upgrade main beam aswell

just with the standard bulbs i have the difference is quite impressive

cheers for the help