ultimate headlight circuits

Subject: 1975 C10 4x4 race truck.
I have all new wiring. Everything to my fuse boards is 2/0 welding cable. Ground is directly to the battery.

I have ECE 90/100 H4 Hella 7" Headlights. I want basically each headlight to have its own circuit with minimal to no voltage drop. I have been considering dual Volkswagen latching relays.

What do you folks think would be the ultimate headlight circuit setup?

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built not bought

For headlights, grounding to the chassis (or engine) may be better.
I run their GND to both nearby chassis and off to batt-.

I also have individual common SPST relays for each individual beam. (Though I use "universal" SPDT relays, and recently combined each beam into one relay - hence 3 relays instead of 6 - but that will be undone in the future.)   

My relays are direct in line (shortest route) between the alternator/battery and the lights.
The bulb power is from the alternator (ie, when battery supplied, the path is batt+ to alternator+ to headlights) since - though maybe pedantic - its for brightest lights when driving.
I have a good engine to chassis bond (ground strap).
I design my wire gauges for a max 0.5V drop at the lights (including the GND path).


I would use controlling circuitry (such as latching relays) to control those relays. (Though I'd probably use circuits instead of relays - eg, the 4017 counter as used in SAAB headlight relays.)

I also use links (fuses actually) to enable configuration for outer lo/hi beam switching ELSE full-time low beams (with inner beams being for high beam) as used on many modern 4-headlight etc vehicles (eg, BMW).

Perhaps you may show us an illustration or diagram?

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built not bought

No diagrams. IMO none needed - it's just relays from normal selector or trigger circuits.

The novelty is how each relay is powered.
IMO it there should be 2 separate paths, whether for a left/right split (the modern norm) or a hi/lo split.

Though not ideal, I have a single BIG flink (fuslelink) of 60A or 100A which splits into two 30A self-resetting circuit breakers which then go to each relay each with its own 10A (else 15A) self resetting CB. Hence any "filament" CB should trip before the "master" 30A, and they should trip before the (theoretically) never tripped flink.   

However my flasher (ie, passing/overtaking hi-beam) is powered independently to the beam switch hence at least providing independent hi-beam triggers should the normal beam circuit fail.
I may later add parallel relay(s)with independent CB(s)from the battery.
Though no protection against bulb etc shorts (which should be isolated via their independent CBs), that is a backup in case of normal circuit beam-switch failure. (I like redundancy - ie, backups in case of "normal circuit" failures.)

Would you elaborate for the circuits/ 4017? Please.

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built not bought

See head and park lights on with momentary sw.

You can also google 4017 datasheet.

Are 5 terminal (30,85,86,87,87a)spdt relays the same as a vw latching(30,56,56a,56b,s) relay?

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built not bought

no they are not

Thought I'd add my own experience wiring my 'i82 ford mustang GT head lamp system that was the best lights I've ever owned.

I replaced the stock sealed beams hi/low + Hi units with Hella H4 lamp assemblies and then ha 100/140 W H4 bulbs that were available in the 80's and wired each filament to a relay using 12 AWG wiring with less than 1 foot run from relays and used 10 AWG wiring to the battery. THE LIGHTS WERE VERY BRIGHT and ran hot and nothing on the road was brighter than me. I must stress that when using for street driving, aiming lights correctly is very important and I was never bothered by police for my white lighting. My marchal airports 35 driving lamps had similar wiring with 130W H2 bulbs and were excellent   I kept them when I sold the car and plan to use them on my current install on my 2009 ford escape. With the following.

Cibie Airport 35 clear driving beams with 130W H2 bulbs along with PIAA 2100XT Fog lamps with 130W H3 bulbs. The wired assembly's of the PIAA's appear to be 16 AWG so I re-wired them with 12 AWG with pigtail connectors and plan to wire each light with its own relay using OVERKILL 8 AWG wiring to each light for minimal voltage drop to maximize light performance for a 5 to 7 foot run. The driving lamps will be placed in lower Center section of bumper area with fog lamps on outer section.

Here's where I need a bit of assistance, I find that the factory lights are completely useless to my high standards and may put a SPDT switch for supplying switched power directly from the stock fog lamp switch from therefore supplying power to either stock fog or PIAA Fog lights. The new PIAA lights should be able to be on both during low and Hi beam as my supply trigger will be from switch & parking lamp feed.

I would like to know if there is a nifty relay setup or relay SPDT OR DPDT SWITCH / diode COMBO DIAGRAM FOR THE FOLLOWING Scenarios;

A) Lo beam & Factory fog on
B) Lo beam & PIAA fog on
C) Lo beam & Factory & PIAA lFog on

And same when using Hi beams as well

*** THIS VEHICLE IS EQUIPED WITH DRL BY CANADIAN REQUIREMENT ***

I have come up with some drawings but this is a tough one... ANY THOUGHTS?

Thanks

Are you for real??? Having high beams and fogs on at the same time is a total contradiction. There's a reason the car manufacturers wire the fogs to go off with the high beams, and to my knowledge, have never built a vehicle with true driving lights. Fogs are a wide low beam, meant to cut under the fog (or heavy snow), and therefore, are shut off with the high beams, because you will not benefit, or see, the fog lights, no matter how bright, with the high beams on. A driving light is a narrow long beam, that if not properly adjusted, can blind oncoming drivers, which is one reason the car manufacturers don't install them in their production cars. Often, especially with PIAA, you can have a driving light much brighter than most factory installed high beams. Do yourself a favor, keep the fogs with the lows, and get a set of PIAA driving lights and wire them with your highs, just make sure they are properly adjusted. I can't believe
how much people spend on lights, but the reason is usually for LOOKS,
rather than for their proper FUNCTION. You know, there are times when JUST fog lights, is better than fog lights and headlights.

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Quality takes time.
"It's better to lose a second of your life, than your life in a second."

I don't disagree. In fact it was illegal here to have fogs on with headlights.
However it now seems commonplace to have "fogs" on with main beam(s). I suspect because modern "fogs" are not really fogs (wide & very low beams) but are clearance or DRLs etc.


FYI - When rally driving I used highbeams (spots) in fog, but that was when competing way faster than visibility (and selecting which "gap" to drive thru before knowing if that was the road).
But that mode is incompatible with public driving (and it's illegal to use high beams into oncoming traffic etc).   
Hence if foggy - true low mounted spread lighting is required and no main beams or other bright lights.

For real? Yup, I just pinched myself.. I managed to figure out a viable switch sequence that will work and offers priority over driving lamp and fogs separately and simultaneously depending on switch sequence. Yes I agree that most lights made these days are made to appeal the cool look and less on functional value. This is why I have modified my PIAA light with heavier gauge Eire as I tested by hooking up to a battery without charge circuit present and there was a very noticble difference of brightness to the in modified light. I decided to run the 8 AWG wire to the lights and will complete this when I return from Vacation. I still like my cibie airport 35 series Driving lamps and look forward to having them mounted. I know it's old school but they do work well. A lot of the lights made these days just shoot a lot of glare with xenon bulbs that have great claims of power,,, gee who they trying to fool?   There is no way to get 130 watts equivelant power from a 55 W xenon bulb!, seriously... All they did was change the linemen colour.   Pure power with pure power is the only way. Btw. When I used to turn my lights on my mustang... The alternator laboured a bit.. Now that's working it baby!

Thanks for your interest