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resistor help

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Hi all,

I'm wanting to look again at making a set of rear lights for my car as I'm picking up a spare set.

I'm not changing lenses so I'm planning on just running white LEDs throughout.

However, I'm looking at these light strips as a nice easy solution to mounting the LEDs.

So, my thoughts then turned to the brake on/off scenario.

Would I be correct in thinking that I'd need to run a resistor on the feed from the "lights" so that the LEDs run at a reduced power? How would I then switch this to the "correct" feed when the brakes are applied?

I'm new to this sort of stuff, but like to think I can learn quickly.

These are the LEDs I'm looking at. Anyone know what the difference is?
**broken link removed**
and
**broken link removed**
and
**broken link removed**

Any help would be greatly appreciated.

Many thanks,
Anthony
 
Last edited:
Check the attached circuit.
The value of the resistors is dependent on the current required for what ever LEDs you buy, whoever you buy them from should be able to help.
 

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Hi Centretek, thanks for posting that.

Ok, so I'm looking at the products I linked to above, and they're all 12v strips, so that to me would suggest that I wouldn't need R2 from that diagram, is that correct?

If so, then I would just need R1 for dimming the LEDs down to " lights" level, and a diode on the "brake light" power feed.

Obviously from here I'm going to ask what diode would be needed?
R1 I could play around with until the required "dim" level is reached.

Another thing with these LED strips, it says you're able to cut them down to divisions of 3. So you can run for instance a length of 9 leds. Now, would this still produce the same light output if pluged to a 12v source as a full strip of 24 would for example?

This is where I start to get confused.

Many thanks,
Anthony
 
If I understand the description on the web site, you can rewire as below.
 

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Roff, thats not too disimilar to how I understood it. Except with the bridge being between the blocks of 3 rather than off the feed.

Think I'm gonna have to buy 1 set and have a play round with them.

Any ideas on the diodes at all that were mentioned in post 2?

Many thanks,
Anthony
 
cantfindausername said:
Roff, thats not too disimilar to how I understood it. Except with the bridge being between the blocks of 3 rather than off the feed.
What do you mean by this? The top strip (as purchased) shows the bridge being beween the blocks of 3.

Think I'm gonna have to buy 1 set and have a play round with them.

Any ideas on the diodes at all that were mentioned in post 2?

Many thanks,
Anthony
1N4001 should work.
 
In Canada, it is illegal to change lights on a motor vehicle. The law states the minimum brightness, the colour and the minimum angle of visibility.

Some kids changed the lights on their little Honda cars and you can barely see them. I think they are rear-ended more than the cops can catch them.
 
As well as a minimum brightness there's also a maximum brightness - you don't want to blind people.
 
All the stupid SUVs and pickup trucks have their headlights at the same level as the eyes of car drivers. Their daytime running lights are high beams and are much brighter than the dimmed lowbeam daytime running lights on cars. When it is cloudy then they blind everybody.
 
Centretek has a good idea, but I would put a diode in series with R1 so the brake lights don't try to illuminate the entire parking light circuit.
 
audioguru said:
All the stupid SUVs and pickup trucks have their headlights at the same level as the eyes of car drivers. Their daytime running lights are high beams and are much brighter than the dimmed lowbeam daytime running lights on cars. When it is cloudy then they blind everybody.

Driving on the south of Vancouver Island or near Vancouver on the mainland is crazy at night. I don't think city drivers even know that headlights can be aimed, much less how to do it correctly.

Up north where people spend most of their driving time on the highway, most people know about it and set them so they don't blind everyone else.

I rented a minivan for a short tour a couple of years ago. When I brought it back in Vancouver I complained about having had to pull over and buy a screwdriver so I could aim the headlights properly (truckers kept high-beaming me because I was blinding them). I got a blank stare from the rental agent.


Torben
 
Was the van with its headlights aimed too high a Mercedes-Chrysler? They blind everybody.
 
audioguru said:
Was the van with its headlights aimed too high a Mercedes-Chrysler? They blind everybody.

Nah, it was a Dodge something-or-other. But the Mercedes with their blue laser headlights from hell blind you no matter how they're aimed.


Torben
 
The LED rear lights will only go on the car if I am satisfied they meet my requirements for brightness of both the "lights on" and "brake lights".

As for the "laser blue" headlights, they're HID (High Intensity Discharge) and they are quite possibly the best things you can fit to the front of a car. I've just fitted some to my daily runner and they're give off pure white light. Over here though, we have the MOT, and light beam direction is tested, and you will fail if they're not adjusted correctly. Maybe canada needs the same thing?

The last thing I want is someone to run up the back of my car after I've spend the last 3 years and many thousands of pounds on her, so I will make sure they're to an acceptable standard of brightness before final fitment. As for them passing an MOT, well thats why I'm doing it to a spare set, so I can swap back to stock for the tests.

I would recommend anyone to get HID front lights though. Needless to say I'll be fitting a set to the front of my hobby car too :)

Back to the wiring...

I think I will get a set of the LEDs, and check on here if I have understood the wiring procedure correctly before I go any further.
 
Mercedes-Chrysler make Dodge cars and trucks and Jeeps and use their high beams as daytime running lights without dimming them.
All other vehicle manufacurers use low-beams and dim them as daytime running lights.

Many people drive at night with "parking lights" instead of headlights because the dimmed daytime running lights are on. When the headlights are switched on then they are at max brightness.
 
cantfindausername said:
I'm not changing lenses so I'm planning on just running white LEDs throughout.

White LEDs are a lot more expensive and need a bigger voltage than red LEDs. It is a lot easier to use red ones where there is going to be a red filter over it anyhow.
 
Diver300 said:
White LEDs are a lot more expensive and need a bigger voltage than red LEDs. It is a lot easier to use red ones where there is going to be a red filter over it anyhow.

The place I've found to get them from are the same price regardless of colour. Maybe a list of potential suppliers would be usefull at this point.
 
cantfindausername said:
As for the "laser blue" headlights, they're HID (High Intensity Discharge) and they are quite possibly the best things you can fit to the front of a car. I've just fitted some to my daily runner and they're give off pure white light. Over here though, we have the MOT, and light beam direction is tested, and you will fail if they're not adjusted correctly. Maybe canada needs the same thing?

Some provinces might have that; I don't know. Motor vehicles are a provincially-governed thing, not federal. I only know what we have in B.C. :) Last year in Richmond (suburb of Vancouver) there was a massive licencing scandal where it was found that over two thousand drivers had bribed a couple of licencing examiners to give them their licences without passing (in some cases without even *taking*) their tests. Given what drivers around there are like, no-one was surprised.

I'd agree that HIDs can be worth it but with a bunch of "ifs". If the installer knows what they're doing. If the wiring can handle it. If the reflectors and lenses are up to the task. If they're aimed properly (even more important with HIDs than with i.e. halogens). And if you like the colours. If someone put a gun to my head I would use them, but only in the extreme non-blue temperature range.

I use the best halogens I can find for my truck and maintain them and I'm happy. Different strokes I suppose. Sometimes I see ones on the road which are not blinding/glaring. Most of the ones I see aren't set up right, so I'm biased against them (fairly or not).


Torben
 
The HIDs should only be used with clear leses. If they are "lined" lenses then it diffuses the light and messes it up. The HIDs you get on eBay are a straight replacement. They plug into the stock light source and don't put any extra strain on the wiring as the wattage is lower than normal Halogen lights. Think its like 35w but 20kV or something like that. As for aiming, mine followed (exactely) the light pattern that my halogens had. But the light output is seriously, and I kid you not, 2000 times better. Even against my "super white" halogens! I was happy with my halogens until I got my HIDs :)


Mine was not a "boy roy" modification, I went for the 6000k HIDs which are pure white. Non of this blue tint. Although my eyes are still not used to seeing things in colour at night, something with that just seems wrong lol
 
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