Technical Headlight wiring upgrade

[Twink80]

I saw a video on YouTube from AutoBella showing a wiring upgrade for the headlights and wondered if anyone had tried it?

The kit is a couple of relays supplied by power direct from the alternator
It would seem to make sense having a more direct power supply rather than the cumulative voltage/current drop in the standard set up. (As standard the full voltage and current for the headlights comes from the ignition switch via the headlight switch and then the column stalk hi/lo through fuses eventually to the headlights. This cant be great for the switch contacts either around 5amps per light)

Driving back on unlit roads a couple of nights ago, above 60mph was pretty sketchy on dip beam so I’m going to try the mod with my own relays on dip first

 

[bugsymike]

I saw a video on YouTube from AutoBella showing a wiring upgrade for the headlights and wondered if anyone had tried it?

The kit is a couple of relays supplied by power direct from the alternator
It would seem to make sense having a more direct power supply rather than the cumulative voltage/current drop in the standard set up. (As standard the full voltage and current for the headlights comes from the ignition switch via the headlight switch and then the column stalk hi/lo through fuses eventually to the headlights. This cant be great for the switch contacts either around 5amps per light)

Driving back on unlit roads a couple of nights ago, above 60mph was pretty sketchy on dip beam so I’m going to try the mod with my own relays on dip first

My only thoughts are would the fluctuation of an alternator supply direct going from min volts to max give the bulbs a harder time than a more consistant/damped steady voltage from the battery?

 

[Twink80]

My only thoughts are would the fluctuation of an alternator supply direct going from min volts to max give the bulbs a harder time than a more consistant/damped steady voltage from the battery?

I think the output is rectified and stabalised if you have a modern enough alternator, but I agree and I would probably use the starter motor cable which runs straight from the battery

 

[bugsymike]

I think the output is rectified and stabalised if you have a modern enough alternator, but I agree and I would probably use the starter motor cable which runs straight from the battery

Yes I agree alternator AC output is rectified and most have solid state control managed by the ECU in later systems, they also shut down/reduce alternator output when extra engine power is required as modern alternators are quite high out put.
Mind you there must be some limit of output reduction, otherwise headlights would dim the faster you went, a bit like old fashioned vacuum operated wipers when I was an apprentice , the more throttle, the less vacuum so the wipers slowed down, happy days.

 

[bugsymike]

There is high voltage bulb kits with transformers to emulate some of the really bright lights on some new car.
A good headlamp reflector design can make quite a difference.
Many years ago I converted a BSA Road Rocket dynamo to 12 volts and fitted a Cibie concave headlamp with a Halogen bulb into the headlamp nacelle, that and the twin 12volt airhorns discouraged motorists who objected to being passed.

 

[Twink80]

There is high voltage bulb kits with transformers to emulate some of the really bright lights on some new car.
A good headlamp reflector design can make quite a difference.
Many years ago I converted a BSA Road Rocket dynamo to 12 volts and fitted a Cibie concave headlamp with a Halogen bulb into the headlamp nacelle, that and the twin 12volt airhorns discouraged motorists who objected to being passed.

So thanks to someone recently posting some excellent wiring diagrams I have had a bit more investigation into my wiring.
My car is 1980, was FI now carbs. About 10 years ago I replaced the bullet fuses with blades and simplified and deleted a big chunk of the wiring ie seat belt warnings, buzzers, chimes, all the FI stuff etc but there were still many random circuits I didn’t get to
This started trying to understand where I was losing voltage in the lighting circuit and whether to relay it or not
Im still learning the circuit logic and am making progress but have also learned a lot so far! Summary below
There are several heavy cable circuits running directly from the alternator/starter solenoid/battery into the cabin. These are not fused and will carry 40-50 amps then could set the car on fire!
Fit a battery isolator that can quickly disconnect the power from the battery.
In the past I was only worried about out battery drain down, now I want to be able to shut off electrical power quickly!

Most of the big power circuits, lights etc, are switched on full load, this was cheap and the way things used to be done. Often the switch would burn out and you just replaced the switch (fine if you can get them)
These circuits also pass through a number of connector blocks and if the connector pins aren’t super clean, there is a resistance and you lose voltage.
Eg the lighting circuit goes from the ignition key barrel to the light switch, through an 8 way connector upto the column switch and back BEFORE it gets to the fuse box through the fuse and on to the headlights
Each headlight has an 8amp fuse, but that only protects from the fusebox to the headlight. The circuit upstream of the fusebox is completely unprotected!
Hence fit a battery isolator.

Clearly this design approach has done the job, cars in regular use probably work fine.
Cars that are used occasionally are likely to present many random problems as circuits deteriorate or partially fail! Use it or lose it!

Im still tracing the volt drop in the lighting circuit but for info with 12.9v at the battery by the time power gets to the loom under bonnet its down to 9.5v hence dim ish headlights!

When I get a solution I’ll update this.

 

[bugsymike]

Lot of old copper wiring goes black inside plastic sheathing causing issues. Had it on Peugeots and even a more recent Skoda, it wouldn't even take solder miles up the loom.

 

[Twink80]

So thanks to someone recently posting some excellent wiring diagrams I have had a bit more investigation into my wiring.
My car is 1980, was FI now carbs. About 10 years ago I replaced the bullet fuses with blades and simplified and deleted a big chunk of the wiring ie seat belt warnings, buzzers, chimes, all the FI stuff etc but there were still many random circuits I didn’t get to
This started trying to understand where I was losing voltage in the lighting circuit and whether to relay it or not
Im still learning the circuit logic and am making progress but have also learned a lot so far! Summary below
There are several heavy cable circuits running directly from the alternator/starter solenoid/battery into the cabin. These are not fused and will carry 40-50 amps then could set the car on fire!
Fit a battery isolator that can quickly disconnect the power from the battery.
In the past I was only worried about out battery drain down, now I want to be able to shut off electrical power quickly!

Most of the big power circuits, lights etc, are switched on full load, this was cheap and the way things used to be done. Often the switch would burn out and you just replaced the switch (fine if you can get them)
These circuits also pass through a number of connector blocks and if the connector pins aren’t super clean, there is a resistance and you lose voltage.
Eg the lighting circuit goes from the ignition key barrel to the light switch, through an 8 way connector upto the column switch and back BEFORE it gets to the fuse box through the fuse and on to the headlights
Each headlight has an 8amp fuse, but that only protects from the fusebox to the headlight. The circuit upstream of the fusebox is completely unprotected!
Hence fit a battery isolator.

Clearly this design approach has done the job, cars in regular use probably work fine.
Cars that are used occasionally are likely to present many random problems as circuits deteriorate or partially fail! Use it or lose it!

Im still tracing the volt drop in the lighting circuit but for info with 12.9v at the battery by the time power gets to the loom under bonnet its down to 9.5v hence dim ish headlights!

When I get a solution I’ll update this.

I now have a plan!
Im going to fit relays near the fusebox. The relays will be switched by the existing feeds from the column stalk after passing through the upstream circuit and switches. Since its only switching a relay coil now the voltage drop wont affect the headlights. The relay coil output is wired back to the fuse box and the headlight fuses and circuit beyond remain the same
Power to the relay coils will come from the power distribution connector C17 (direct from alternator/starter solenoid & battery)
Sketch below
This logic could be used for all other high power circuits that switch directly, on my car I dont think there is anything else as the horn already runs through a relay and I dont have power windows