Hi Everyone,

I've decided to fit some DRLs to my sport, I'm going to fit rings in the headlight housing. I'm currently unsure on a couple of things, the first is whether to go for CCFL or CREE when it comes to the rings. As I'm fitting them inside the headlight I only want to do it once, I'm leaning more towards CREE as I've used CCFL rings previously in computer cases and they've lasted for about a year (and that's without being exposed to the elements, vibration and bouncing).

The second, third and possibly fourth things are related to the actual wiring. I've drawn up a very rough and ready wiring schematic for how I intend to wire the DRLs in, but knowing pretty much nothing about electronics is making realisation a little awkward.

So starting from the top,

I will wire each headlight individually and keep all wiring/modifications within each headlight as reading round the forum I've read that there is an ignition live in the existing loom, that and you can buy pre-modded headlights that are plug and play.
The DRL controllers on the market at the moment only have a single sensor wire. So with this in mind I will use a few basic components so the single sensor wire can switch the DRLs off when headlights are on (I still want them on when the sidelights are on) and to switch off the appropriate side when indicating (Hence treating each headlight individually with separate DRL controllers in each).

So by splicing the sensor wire into the headlight and indicator feeds I get the appropriate signals, however I have to fit a diode from the headlight to the sensor to prevent back flow and the same for the indicator. But this means that when using the indicator the DRL will flash in tandem with the indicator. The way I have (potentially) resolved this is by adding a capacitor. The cap will charge with the indicator pulse and provide a signal when the indicator is between flashes, at this point I will have to fit an additional diode between the cap and the indicator to stop reverse flow again. Finally, as the sensor wire is just that, I need a way to drain the cap, so by adding an earth after the cap and before the diode that prevents back flow from the headlight. To prevent the cap from instantly dumping all power via this new earth I need to fit a resistor and along with the size of cap then balance the two so that the DRL stays off while the indicator is on and then switches back on around 1 second (preferably as soon as possible) after the indicator has been stopped.



The point at which I fall down is knowing which cap, diode and resistor to use... so nothing major

I've done no testing so far (switching point for the DRL controllers being a fairly important factor), and think that may well be my best route forward, but was hoping that someone on here may simply know off the top of their heads which components will suite my purposes.

So for the diodes I was thinking of using 1N5404, a 1uf 50v Cap and based on a 12v 2a circuit (24w) providing a circuit resistance of 12 Ohm I think a 20 Ohm resistor would slow the bleed just enough.

But I'm not really sure if my maths or even theory is correct, so any and all advice is greatly appreciated.

most cars don't have an ignition live at the headlight (despite some bloke from Oz keep saying there is).
Only cars with optional AFS has it. You car will have an orange headlight icon (forward facing with arrows) in the speedo if you do have this.

You can by controllers which connect to the indicators to shut them off.

This maybe the best route. You don't want to be designing your own circuit and having it keep failing within the sealed headlight.

Ensure circuit/LED's will run at 15V

Consider putting DRL's into fog lights as much easier to access.

Thanks for the reply Andy,

AFS is standard on the SC, so I've got the ignition live. But unfortunately after spending a couple of hours on ebay I couldn't find any controllers that tie into the indicators. I contacted hids4u as they had previously sold them, but they informed me that they no longer stocked them as the manufacturer had stopped making them. but if you can find some then I'd love a link as it would save me a lot of work.

I had looked at fitting the DRLs in the fog lights, but I think it will look more professional/factory if fitted within the headlights.

Not sure why my own circuit design would keep failing though, non of the components listed are dealing with high voltages or known for being unreliable (other than the LED's or CCFL), the only reason they would fail is if they aren't spec'd correctly. Luckily all the components generate heat when they work, so by bench testing I will be able to ensure that they aren't getting too hot, if they are I simply swap the component out for a more robust one. But I was hoping that someone with more knowledge around electronics than myself would be able to point me in the right direction.

DRL controllers seam to have changed since the last time I looked.

THere are several on ebay which connect to the indicator wires, however the words seam to sugguest the DRL would flash with indicators rather than dim.


this one doesn't say what it does.

http://www.ebay.co.uk/itm/12V-LED-Day-Runn...SwIxxZoTIw

On my old RR I fitted drill rings.
I ran the earth to an existing earth, and the positive I ran to the fuse box in the engine bay as there is an ignition powered spare fuse socket.
DRL came on when ignition was turned on and then went off when ignition was turned off, auto headlights remained as normal

Andy K wrote:

most cars don't have an ignition live at the headlight (despite some bloke from Oz keep saying there is).
.

Best way to off a Kiwi, call him an Ozzie

Well I ordered some flexible drl strips to see what they are like.
Tested how bright they are and are very bright indeed.
They can be fixed around curves etc so are good to go.
Just need to see how to fix them inside headlights to give an original factory style finish

Quick update:

All parts have arrived and I've done some testing, it looks as though the Cap I'm using (1000uf) is too big, I'm getting a delay of just over 5 seconds before the LED's brighten again after I simulate a pulse from the indicator.

So a bit of simple maths would say that 200uf will equate to around 1 second delay in my circuit, so I've ordered a 220uf Cap and I'm hoping that, resistor dependant, I will be able to get the delay to around 1.5 seconds.


For anyone who's interested I bought these halo rings: https://tinyurl.com/yc3wqby2

You'll need the 120mm ones. I'm really impressed with how bright they are, the control circuit isn't integrated into the LED PCB so if it should fail it can easily be replaced without having to strip the headlight to replace the LED ring.

Pls post pic when done.

Socast wrote:

Quick update:

All parts have arrived and I've done some testing, it looks as though the Cap I'm using (1000uf) is too big, I'm getting a delay of just over 5 seconds before the LED's brighten again after I simulate a pulse from the indicator.

So a bit of simple maths would say that 200uf will equate to around 1 second delay in my circuit, so I've ordered a 220uf Cap and I'm hoping that, resistor dependant, I will be able to get the delay to around 1.5 seconds.


For anyone who's interested I bought these halo rings: https://tinyurl.com/yc3wqby2

You'll need the 120mm ones. I'm really impressed with how bright they are, the control circuit isn't integrated into the LED PCB so if it should fail it can easily be replaced without having to strip the headlight to replace the LED ring.

I don't think you understand what I'm trying to achieve. The delay in brightness is by design..

If I simply wanted them on with the ignition that wouldn't be difficult to do, but I'm pretty sure that the law will be changed soon to ensure that they have to dip when headlights are on (due to them dazzling other road users in low light/the dark), so I want to use a controller that will dip the DRL's for me when using either the headlights or independently when using the indicators.
As there are currently no DRL controllers on the market that have these features I'm creating a simple circuit to modify an existing controller to achieve my goal.

No problem, was just trying to be helpful.
Hope all goes well, look forward to results.
Be interesting if law did change as my other car drl lights don’t dim when lights illuminate (bmw)

I didn't mean to come across as rude and apologise if I did.

No need to apologise, not offended at all.
Always healthy discussion.
Look forward to your work too