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Dual brightness driving lights

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nasty gurl

New Member
Hi everyone. I was just wondering if there is a very simple circuit that I can make in order to have fog/driving lights on my car always on (when the ignition is turned on) but a low intensity and then have a switch that allows me to turn them on full beam when needed in reduged visibility/fog etc. Is this possible? Can someone please help me out here.

Thank you very much
 

tansis

New Member
Can u tell us the wattage of the lamps please, this will help to find a suitable circuit for your needs.
 

seeker

New Member
Hi nasty gurl,
There are two simple circuits you can build to control your fog lights.
Do you want it fully automatic (as in starts at dim on motor start then goes to bright when you push a button) or switches from bright to off to dim manually?

Thanks, Tony
 

nasty gurl

New Member
Hi thanks for your help. tansis the wattage will probably be 55w and seeker, I just found out that your first option (which I wanted) is illegal so the second option would be great. Thank you very much for your help. I am fine with doing the electrics, just not designing them. Thanks
 

tansis

New Member

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Ocelaris

New Member
What kind of Power Mosfet can you use? I tried a circuit similar to that with a Tip31?

https://www.electro-tech-online.com...rrent-led-tail-lights-eagle-schematics.26306/

I am in another thread, asking basically the same question, I'll repost it here how I am approaching it with limited success... Please feel free to ignore, but I didn't want people to have to repeat themselves, or if someone else missed this thread like I did... :-/

Ok, I have tried this circuit, and it doesn't quite work as expected... Basically I have 8x 350mA capable LEDs 2 sets in parallel of 4 in series... I THINK... I am not sure exactly the load... But I'm trying to get 2 sets of brightnesses for my tail lights. And they're not exactly working how I expected.

First pic is the full brightness, it should be 640mA by the calculation of the lm317 which I am using, which is R = v/A so 1.2/.64 = 1.875 = ~1.9:eek:hm:

If each LED can take 320mA I think 640mA is correct, but I'm not sure if how I wired them is really 2 parallel strings of 4 in series. This is just the way I had to mount them based on my thermal and space contraints... pics to follow of my rationale.

**broken link removed**

Am I really getting 320mA to each LED? I'm a bit confused on the parallel, but I think I am?

Second I intended to run them at 2 different brightnesses, basically 320mA and ADD another 320mA diode isolated of course... but just adding two constant current sources together to get 640mA. It doesn't really work that way, it gets barely if any brighter. This is how I had that wired:

**broken link removed**

Now I was thinking it was possible that the two chips were not functioning properly, crossing each other out or something, so I tried just 1 LM317 with two 3.9:eek:hm: resistors in parallel to get my 1.9:eek:hm: but connecting and disconnecting that 2nd 3.9:eek:hm: resistor which SHOULD have netted me 1.9 ohms just didn't do anything at all... so I'm confused. I thought you can parallel resistors to get R1+R2/2 ?

Since I didn't get "half" of the brightness, I Thought maybe it was a non-linear brightness for power, but according to the SunLED Apollo PDF, this chart shows that I really should be getting about 1/2 the brightness for half the current through these LEDs...

**broken link removed**

So what am I doing wrong? Thanks for all the help. Bill
 

Ocelaris

New Member
nasty gurl said:
Hi thanks for your help. tansis the wattage will probably be 55w

55watts of LEDs is REALLY REALLY REALLY bright and/or heat. I have 8, ~3/4watt each LEDs and I have a CPU heatsink w/fan running on it. Remember LEDs aren't that efficient. So thermal management is going to be your biggest challenge, not the dual brightness...

Here's a nice little chart I found:

**broken link removed**

Even the Lumiled K2s are only 40-50 lumens per watt... and to equal a 55watt regular halogen Foglight (I assume that is where you got your 55watt number) you would be at 1375 lumens / 40 lumens/watt LED = 34 watts of High power LED...

at minimum with the impossible to mount SunLED Apollo PLCC-4 LEDs, you are going to be looking at a chunk of aluminum like 12" x 12" plus at 3$ a pop, 102$ for JUST the LEDs... If you went with the K2 which are electrically isolated, hence easy to mount on a heatsink, you are looking at 9$ a pop... x 34 = wayyyyy too $$$$ I think.

Maybe you need to scale down the ambition of 55watts of LED lighting? I'm a lighting fanatic on HIDplanet if you hadn't noticed...
 

Hero999

Banned
What's wrong with using a compact fluroescent tube if you want such a high power light? It will use 1/4 of the power of all those LEDs.
 

Ocelaris

New Member
It's on a car, so you'd have to make an inverter. and it's not a point source of light. I think she's trying to make fog lights out of a high color temperature light source "blueish white light"...
 

Sig239

Member
WTF, Did I miss something. I don't think nasty gurl said anything about LEDs. It seems to me that she(?) is essentialy wanting to make a fog/daytime driving light combo out of normal 55 watt (halogen?) fog lights.

Also I don't think she said anything about "bluish white light".
 
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Ocelaris

New Member
Whoops, my apologies, I was doing almost the exact same thing with LEDs (dual brightness), and at the bottom of my thread there was a link of "related threads" and I followed that link... I also had in the back of my mind this thread of a similar nature which I've been active on... too many of the same sort of thing and I got them confused:

"Making some new LED fog lights for my BMW..."
**broken link removed**

It was late, and my threads got crossed...

**broken link removed**

**broken link removed**

**broken link removed**

My mistake. But on the off chance she's interested in making some nice looking LED fog lights, this guy has a nice setup if you want to see what he's done, follow that link.
 
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Sig239

Member
Those do look pretty freaking sweet! Of course looking sweet and being legal don't always go together. There are very tight specifications regarding the lighting on your car, especially headlights, and brake/tail lights. You should consider this before driving on the public roads with your light mods.

LEDs may put out less light overall, but it is in a much tighter pattern. The last thing you want is to either blind someone behind you with your homemade super duper bright LED brakelights, or alternately cause them to crash into you because they are at *just* the wrong angle to see them narrow beams; particularly if you are on a motorcycle- think about it! I don't mean to rant, I just don't want to be the one to crash........
 

Ocelaris

New Member
How about this? Simple Automotive Relay, Toggle switch in the cabin, and 20w 5ohm tubular resistor... it's gonna get hot, but that's the easiest cheapest way to run it... somebody would have to redo my math, might need 2 of those, one for each headlight to bring 14.5v (running car voltage) down to ~10volts which I calculated as ~1 amp dropping 4.5v is that 5watts? Or is it 1amp * 14.5v = 15watts?

I used to know where to find a 20$ DRL module, but now they're all 35$ and up, so thought I'd share this... because that's all the DRL modules are.

**broken link removed**
 

Ocelaris

New Member
Sig239 said:
Those do look pretty freaking sweet! Of course looking sweet and being legal don't always go together. There are very tight specifications regarding the lighting on your car, especially headlights, and brake/tail lights. You should consider this before driving on the public roads with your light mods.

LEDs may put out less light overall, but it is in a much tighter pattern. The last thing you want is to either blind someone behind you with your homemade super duper bright LED brakelights, or alternately cause them to crash into you because they are at *just* the wrong angle to see them narrow beams; particularly if you are on a motorcycle- think about it! I don't mean to rant, I just don't want to be the one to crash........

Those aren't my lights by the way... on my car, I don't do anything special, don't need to, have a cage to protect me.

On my bike, and I don't want to steal this girl's thread, but from personal experience, it's ALWAYS someone who doesn't see you who is the problem. It's never happened that people drive head on into too much light.

I run with my high beams on at ALL times (except when behind someone in traffic), I always let up on my brakes when there's someone stopped behind me, exacting every courtesy, but when it comes to driving in the dark, it's life or death, and I'm going to throw every allowable lumen (and then a bit more) of red/orange/white wherever permissible out for my own protection.

I've done my lumens calculations, and I'm within 10% of the OEM specified lumens anyways... It's just that MY lumens are monochromatic, and halogen are filtered, so mine appear brighter... but that's ok, that's what I'm trying to do.

NastyGurl, If you want a better non-schematic drawing of how to do that, let me know I can throw one together with the relay picture... something like this:

**broken link removed**
 

Sig239

Member
Ocelaris said:
On my bike, and I don't want to steal this girl's thread, but from personal experience, it's ALWAYS someone who doesn't see you who is the problem. It's never happened that people drive head on into too much light.
Unless they can't see because they have to close their eyes due to the blinding spotlight type pattern that eminates from LEDs

Ocelaris said:
I run with my high beams on at ALL times (except when behind someone in traffic)
Yeah because, who cares about the oncoming traffic? What do they need to see anyways?

Ocelaris said:
I always let up on my brakes when there's someone stopped behind me, exacting every courtesy, but when it comes to driving in the dark, it's life or death, and I'm going to throw every allowable lumen (and then a bit more) of red/orange/white wherever permissible out for my own protection.
Right, because blinding the people that are driving directly toward you while you are STOPPING, is going to protect you.:rolleyes: Protect your self with that impenetrable shield of light. You'll get the Darwin award for sure!

Ocelaris said:
I've done my lumens calculations, and I'm within 10% of the OEM specified lumens anyways... It's just that MY lumens are monochromatic, and halogen are filtered, so mine appear brighter... but that's ok, that's what I'm trying to do.

Your missing the point. Think diffusion lens. Or how about floodlight vs. spotlight. Light pattern. Or how about Lumens per sq. inch at n feet away. More is not always better, just because a 6lb. sledgehammer works well doesn't mean a 50 pounder would be better.
 

Ocelaris

New Member
I've edited my post because I was quite a bit upset at your comment Sig329...

I'd like you to consider your comments, and please have respect for other's opinions. Take a look at my project if you would, and if, and only if you have experience, and something productive to say, feel free to comment.

I find your comments personal in nature, and that's not how I would treat you, nor would I expect to be treated in return. I like this board, but I find your comments hostile, and unproductive. I've taken a LOT of time, and a LOT of thought into this project, and I don't think you gave it that much respect. Thank you. Bill

*PS* I've posted quite a good rationale for some of the things I do in the long post below. Take a look, and if you still don't agree, please make suggestions. It takes a long time to build something, please realize you're tearing something down without what I feel is a honest look at what I'm doing or where I'm coming from.
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
Ocelaris said:
Do you always come across as an ******* or is it just something I said that made you upset?

Because I'm not sure you understand what it's like to ride a motorcycle and have car's swerve into you and then "think it's ok because they didn't see you".

I passed my bike test in 1972, so I think I'm well qualified to comment on biking! - the only ******* here is YOU, riding with high beam on and dazzling the on-coming traffic. Certainly you NEED low beam on at ALL times, but high beam is illegal, and if I was a police man I'd book you for it - as a member of the public I'd give you a good kicking!!.
 

Ocelaris

New Member
Nigel Goodwin said:
I passed my bike test in 1972, so I think I'm well qualified to comment on biking! - the only ******* here is YOU, riding with high beam on and dazzling the on-coming traffic. Certainly you NEED low beam on at ALL times, but high beam is illegal, and if I was a police man I'd book you for it - as a member of the public I'd give you a good kicking!!.

Seriously... Have you ever driven in the United States? I've driven in the UK, and in the US, and it's a whole different world. There are NO bikes by comparison, and every other car is a yank-tank who is ready to bear down on you...

It's totally legal here in the states, and if it was even a slight inconvenience I'm sure I would've been flashed by now, we're not talking 2 lane roads out in the dark, this is 6 lane with divided median, and very poorly lit highways. I'm suprised a fellow biker would think they're protected enough as is with the meager illumination that bikes have... I'm a bit shocked, I regularly get almost pushed off the road by cars merging onto the highway in front of me because they "don't" see me... and you don't see having your high beam on, or at least flashing the drivers a good way for them to notice you?

Again, I came back from the UK and started driving on US roads again, and it was terrifying, the drivers never pay attention, and it's down right unsafe compared to other countries where bikes are more acceptable.

Go do the math on my project if you think my illumination is out of line, a dual 21w high beam brake light is 20lumens/watt * 21w = 420 lumens per bulb = 840 lumens total. I have 8, 50lumen 1watt LEDs = 400 lumens... Each LED is 120* width, and I figure after the filtering of the halogen light source vs. less filtering of the LEDs, I'm about on par. There's now a faster and more noticeable source of light, but certainly not blinding by any means, these are still behind a diffuser...

Can I get a little support here? I feel like I'm fishing for a little empathy, but nobody seems to either want to speak up or maybe I'm just being an *******? If you know in your heart you've been where I've been, seen what I've seen, and I'm in the wrong, feel free to say so, but I'm yet to see any of that...
 
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Nigel Goodwin

Super Moderator
Most Helpful Member
If a motorbike coming the other way is on high-beam and dazzles you, and you can't see what you're doing - the only safe response is to aim straight for the light - that's the only direction you KNOW you're not going to hit a pedestrian. I would also switch to high-beam to make you aware!.

As for no drivers never flashing you, if you were dazzling me I certainly would!!!.

Obviously the situation is different on large multiple carriageways, but I still see no excuse for permanent high-beam?.
 
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