Potential pitfall with S4 High beam circuit -- edit, NOW with picture!! :)

Nick Gustas · 07-28-2002, 04:45 PM

I've been running 80 watt high beams with no damage to the wiring or connectors, but decided it would be a good idea to check my voltage drop from the battery to the bulb terminals to see if I was getting all the performance I could.

Test 1 had a battery voltage of 13.33 under all conditions, lights on, off etc.

high beams on, low beams on, both high beam bulbs disconnected, 12.88 volts at the high beam terminals. Not that great.

Low beams on, high beams on, one high beam bulb connected, 12.4 volts at the terminals, getting worse.

Low beams on, high beams on, both high beam bulbs connected, 11.5 volts

yuck, bad bad bad... 1.83 volt drop

I went out and bought my typical overkill lighting relay system components.

10ga wire, 30 amp relay and 20amp breaker. I use one of these per filament. My Eldorado has 4 relays and 4 breakers for it's lighting system

Anyway, I mounted the relay inside the housing, ran all the proper wiring. This time battery voltage was measuring 13.43 volts, lights on or off. I tried just this test.

Low beams on, high beams on, both high beam bulbs connected, voltage at high beam bulb terminals was 13.38 volts, MUCH better

I'll take a .05 volt drop anyday.

The difference in output is more than noticable.

S4@last!::Now B7 RS4 · 07-28-2002, 05:04 PM

Looks like you did a lot of work. It would be wonderful if you could provide us a write up.

Nick Gustas · 07-28-2002, 05:16 PM

It does involve punching two tiny holes in the high beam bulb access panel, it was the cleanest way I could find to run the 10ga wire in.

Nick Gustas · 07-28-2002, 06:09 PM

Assuming a 55watt H7 produces 1335 lumens at 12.8v, and looking at other overwattage bulb ratings vs normal ratings, an 80 watt H7 should produce 1942 lumens at 12.8 volts. I made a little chart of 80 watt H7 output at various voltages.

1363 lumens at 11.5v

1484 lumens at 11.8v

1942 lumens at 12.8v

2203 lumens at 13.3v

2610 lumens at 14.0v

Certainly explains the difference in the picture above.

I used this equation to calculate the lumens available at different voltages.

RKA · 07-28-2002, 06:25 PM

Halogens drink more juice...might want to xpost it for them.

Nick Gustas · 07-28-2002, 06:43 PM

If I don't forget I'll repost this monday afternoon, we're all about performance right?

Singletrack · 07-28-2002, 06:51 PM

Singletrack · 07-28-2002, 06:51 PM

System_S4k · 07-28-2002, 07:06 PM

Nick Gustas · 07-28-2002, 07:24 PM

I'm going to do the other side tomorrow night unless something comes up. I didn't take pictures of this side because some of my wiring turned out not so great, it's electrically sound, but not pretty. Ugly yellow connectors, icky grey wires for the relay trigger. 22ga wire going into a 10-12ga connector

Always turns out better the second time around, but I'm not redoing wires I'll only see once a year or less.

I need to find a good set of high current water proof connectors, right now I have the wires come out of the housing about three inches and terminate into non water proof connectors. I need them there so if I ever need to pull the lights it's not a big ordeal. Local stores had nothing so I might have to mail order or hit a marina. Overkill, I know

07-28-2002, 04:45 PM	#1
Nick Gustas Senior Member Account #: 3094 Join Date: Mar 2000 Posts: 7,470	Potential pitfall with S4 High beam circuit -- edit, NOW with picture!! :) I've been running 80 watt high beams with no damage to the wiring or connectors, but decided it would be a good idea to check my voltage drop from the battery to the bulb terminals to see if I was getting all the performance I could. Test 1 had a battery voltage of 13.33 under all conditions, lights on, off etc. high beams on, low beams on, both high beam bulbs disconnected, 12.88 volts at the high beam terminals. Not that great. Low beams on, high beams on, one high beam bulb connected, 12.4 volts at the terminals, getting worse. Low beams on, high beams on, both high beam bulbs connected, 11.5 volts yuck, bad bad bad... 1.83 volt drop I went out and bought my typical overkill lighting relay system components. 10ga wire, 30 amp relay and 20amp breaker. I use one of these per filament. My Eldorado has 4 relays and 4 breakers for it's lighting system Anyway, I mounted the relay inside the housing, ran all the proper wiring. This time battery voltage was measuring 13.43 volts, lights on or off. I tried just this test. Low beams on, high beams on, both high beam bulbs connected, voltage at high beam bulb terminals was 13.38 volts, MUCH better I'll take a .05 volt drop anyday. The difference in output is more than noticable.

07-28-2002, 05:04 PM	#2
S4@last!::Now B7 RS4 AudiWorld Senior Member Account #: 16463 Join Date: Feb 2001 Posts: 2,552	Great Job! Looks like you did a lot of work. It would be wonderful if you could provide us a write up. __________________ 2008 AVUS RS4 Silver leather/CF, iPod adpater Magnaflow exhaust Milltek downpipes Huper Optik Tint and 3m Clear Mask 2007 Q7 Quartz Gray Stock for now

07-28-2002, 05:16 PM	#3
Nick Gustas Senior Member Account #: 3094 Join Date: Mar 2000 Posts: 7,470	Thanks :) writeup will probably happen, need to take pictures of the process It does involve punching two tiny holes in the high beam bulb access panel, it was the cleanest way I could find to run the 10ga wire in.

07-28-2002, 06:09 PM	#4
Nick Gustas Senior Member Account #: 3094 Join Date: Mar 2000 Posts: 7,470	Lumen calculations with sound guesstimates :) Assuming a 55watt H7 produces 1335 lumens at 12.8v, and looking at other overwattage bulb ratings vs normal ratings, an 80 watt H7 should produce 1942 lumens at 12.8 volts. I made a little chart of 80 watt H7 output at various voltages. 1363 lumens at 11.5v 1484 lumens at 11.8v 1942 lumens at 12.8v 2203 lumens at 13.3v 2610 lumens at 14.0v Certainly explains the difference in the picture above. I used this equation to calculate the lumens available at different voltages.

07-28-2002, 06:25 PM	#5
RKA Member Account #: 2062 Join Date: Mar 2000 Posts: 67,038	My guess is that this effect would be more dramatic in the A4's (halogens)? Halogens drink more juice...might want to xpost it for them. __________________ 2005.5 A4 Avant 2.0T Quattro 6MT APR 91/93/100 \| APR Exhaust \| 19" BBS RS-GT's \| Carbonio \| Hotchkis \| Partridge-in-a-pear-tree Others: 2006 TL on the block 2001 S4 sold 2000 A4 sold * September 11th, 2001 - Never Forget *

07-28-2002, 06:43 PM	#6
Nick Gustas Senior Member Account #: 3094 Join Date: Mar 2000 Posts: 7,470	Probably, especially if the car has aged or the bulbs aren't stock. I'll throw a link over there If I don't forget I'll repost this monday afternoon, we're all about performance right?

07-28-2002, 06:51 PM	#7
Singletrack AudiWorld Super User Account #: 25380 Join Date: Sep 2001 Posts: 16,037	Wow, I never would have guessed it would be that drastic a change. __________________ 2008(9?) S5 - ordered 3/29/08 2004 Subaru Impreza WRX STi 2000 A6 2.7T - Sold "On the run from Johnny Law; ain't no trip to Cleveland."

07-28-2002, 06:51 PM	#8
Singletrack AudiWorld Super User Account #: 25380 Join Date: Sep 2001 Posts: 16,037	Please do - I'm interested. __________________ 2008(9?) S5 - ordered 3/29/08 2004 Subaru Impreza WRX STi 2000 A6 2.7T - Sold "On the run from Johnny Law; ain't no trip to Cleveland."

07-28-2002, 07:06 PM	#9
System_S4k Elder Member Account #: 23081 Join Date: Jul 2001 Posts: 18,114	Good gawd. You are gonna burn out someone's eyes. :P We need a write up. :) __________________

07-28-2002, 07:24 PM	#10
Nick Gustas Senior Member Account #: 3094 Join Date: Mar 2000 Posts: 7,470	If I need to use them in anger I want all the power I can get :) I'm going to do the other side tomorrow night unless something comes up. I didn't take pictures of this side because some of my wiring turned out not so great, it's electrically sound, but not pretty. Ugly yellow connectors, icky grey wires for the relay trigger. 22ga wire going into a 10-12ga connector Always turns out better the second time around, but I'm not redoing wires I'll only see once a year or less. I need to find a good set of high current water proof connectors, right now I have the wires come out of the housing about three inches and terminate into non water proof connectors. I need them there so if I ever need to pull the lights it's not a big ordeal. Local stores had nothing so I might have to mail order or hit a marina. Overkill, I know

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