I know this isn't as spectacular as Craig's HUD, but please bear with me..

I'm trying to convert my front turn signals (the one's in the bumper) to LEDs. I ordered some LEDs on ebay, 50 yellow 5mm ones, and am wiring them in series 4 at a time with the advice of Brad92SE (thanks brad!). I hooked 24 LEDs up tonight (enough for one signal; 3 rows of 8). I was going to have a pic for you tonight, but the camera is in my mom's room and she's sleeping



The wire in the middle is the ground and the other wire (that goes around the top and sides is the power). Here's the problem: I went to hook it up to my battery..and one of the LEDs exploded! Which then in turned scared the **** out of me, I think the problem was my n00b was showing and didn't split the leads of the LEDs far enough apart and some were touching. I came back inside and replaced that LED and noticed inside some of the others their seems to be burn marks, or something to that effect. I went and tested it again and it lit up for about a second then died, and now won't light up again...I don't know?? Can anyone help me?!

 

did you wire in the resistors for the LED's to work on 12 volts or did you just hook them in.....

 

I did not wire in resistors because I was told wiring them in series would lower the voltage in itself and I would not need resistors

 

did you calculate how many leds it would take to equalize the voltage ? dammit wheres my calculator....

 

yea, wireing them in series does lower the voltage you might try putting them in rows of 5 assuming that they are 3v resistors because you are actually working with 14.4 volts, not 12....

 

This is where Ohms Law comes into play

 

I saw some of these in my Mustang mag recently. They are for a '66, and the way they made them was by mounting a board with the leds on it to a connector that just twists in to the existing bulb socket. Pretty cool...looked pretty simple to make, and they wanted like $50 for the pair.

 

yea, its really easy
the problem is that you calculated for an even 12v when a car is running the electrical system actually runs at 14.4v not 12v, so using 5 leds for a total voltage of 15v rather then 12v with 4 because 4 * 3 is 12 and 5 * 3 is 15...use 5 led's and you'll be fine....

 

yeah you have to calculate it with ohm law look it up in google its fairly easy but you have to know the specs on the led and also if you wire up the led to your turn signal your blinker is going to go ape shizzy because the leds consumes less power than a regular 1156 so the flasher is going to think the bulb is burnt out hence your blinker is going to blink like its on crack

 

just buy some resistors man...

Oye ve.

Brian

 

The number of leds in the series shouldnt be a problem, but you could try putting 5 in each row just to be safe. My dome light just has the 4 led's, but the specs on your led's may be different. Just make sure that none of the leads are backwards, and try hooking up each row to a power source to see if they are all bad or just a few are.

 

The voltage drop across a standard LED (non-flashing and non-IR) is around 1.6 to 1.7 Volt with 30mA (typical current) flowing through it.

4 or even 5 LEDs (standard) in series will therefore quickly bite the dust as you have discovered - the change in voltage drop with higher (even 2 amps) across a LED is virtually nothing - ie - if you run 2A through it it will still only drop around 1.6 or 1.7 volt.

You will have to fit a resistor in series or you gonna spend alot of money on blown LEDs - the car's battery voltage varies between about 12 and 14.6 with a normal charging alternator - the voltage difference is therefore around 2.5 V wich is way greater than anything the average string of LEDs can handle while staying whitin their current limits.

At 1.7V per LED I would:

Fit 5 LEDs in series, and also add, in series, a 180 Ohm resistor rated at 5 Watt (for safety) for 12 Volt operation.

You can then make up a few of these "combinations" and hook them up in parallel to give greater light output.

 

Read this LvR's post as he's right. Even in series you're not going to get enough voltage drop at the first LED even with 10 LED's. Wiring in parallel with a resistor def gives a much higher light output.

You're also going to have to fool the flasher into to thinking it has a standard filament bulb there.

Hey LvR - good to see a Japie on the org! Do SA max's have reflectors in the rear bumpers like Kiwi / Aussie max's?

 

Hi

Short answer - no. Have some "mist" lights in there though.

Some pics of the local VG I own posted in this thread

 

Hi LvR (am guessing the v stands for van...)

Those bumper lights look like foglights, but am I correct in saying they use a low wattage bulb mounted in the side of the housing and not at the back? Kiwi / Aussie Max's have reflector blanks there, although I've modified mine to be almost like true OE foglights (the lens is different).
This is my cardomain page: http://www.cardomain.com/id/nismobaron Page 3 has the rear foglights.

As for the sluggish problem you were having, what grade of gasoline do you run? How is it measured in SA? RON or FON? In NZ we use 91 RON (equivalent to US 87 FON!!!).
I didn't read all the posts, have you done a compression test?

Anyways, if you need small parts like knock sensors, pm me as I see a few of our Max's in my favorite breakers yard, and the prices are really cheap (the downside is it's a U-Pull-It operation, so you can't tell if the part is good or not). As an example, power mirror = NZ$16 each, complete.

 

Quite correct yeah - Just as with "van"

Fuel here is 93 RON leaded - also some guys keep 91 unleaded. Personally try to stick to 93 while its still available. Compression done, and all well balanced and as per FSM spec.

"Sluggishness" investigation came about because I drove another VG auto that seemed a lot more responsive even though it wasn't even close to as well cared for as my vehicle.

Thanks for the offer on the parts - will keep it in mind if I do need something. (pretty sure I don't need a knock sensor after all the tests and the 17 degree timing thing discovery).

 

93 RON = US 89 FON, so shouldn't be sluggish, except it's LEADED - the VG30 is designed to run on unleaded, and the ecu might be trying to retard the timing to compensate and/or the O2 sensor / cat converter aren't working properly as a result of subsequent lead contamination. I'm almost certain the other car you drove was running on 91 unleaded.
Try running your car on 91 for a month or so and see if that helps.

BTW: leaded gasoline is really bad for your health, the environment and your country's health!!! I'm guessing it's cheaper than unleaded, as wouldn't be sold otherwise.

 

How did we go from LEDs to gas mileage??

Dmad - user THIS to calculate what resistor to use. That's what I'm using to finish off my taillights, and I've had no problems (except no money - but that's a whole OTHER monster).

Good luck!

 

At the risk of really high-jacking DMad8724's thread :

Few things:

1. Quite aware of the lead and atmosphere issue - same price here.
2. Locally we do not yet have forced emission standards wrt vehicles - so no CATs, EGRs etc etc fitted at all.
3. Nissan SA says I must drive leaded - they have to do some mod (which I certainly question!) in 2006 when leaded fuel will no longer be available here.
4. Timing getting adjusted because of wrong fuel? - well dunno about that one personally. According to the FSM diagrams, I concluded that the timing curve is pre-mapped for the engine with a fixed ref point as defined by the initial timing (ie non-dynamic) and the only possible external sensor able to affect timing at all is the knock sensor. (Sure engine speed and vacuum has an effect but thats also pre-mapped). Unless I am therefore driving rally grotty fuel even worse than 91, I don't see how timing is going to be retarded. (carbon deposits just about absent when I inspected inside of combustion chamber and underside of heads with a inspection scope so that cannot be the cause for pre-ignition either)

If you or anybody else have any detailed info on the engine timing mapping and the influence of particular sensors on it used on the VG I would be most interested - been visiting any and all forums sites I could track down and couldn't find any details to contradict the FSM.

Thanks for the interest and comments.

Perhaps if you have any further thoughts we should head back over to my original thread.

 

nubiannupe

Nice find there - its designed for a single LED though. If you want to use the calculator you gotta add the forward voltage dropps of all leds used in series together or else things will really be dark with a too-big resistor.

 

resistors are ur friends... the amount of current an LED takes is too small to induce enough resistance on a 12V system to run other LEDs. just wire in the resistors! 1 to each array of LEDs.

 

Dmad, what are the specs on your led's? If your leds are anything like mine, which have a max current of 30mA and a typ voltage of 3.5V, an overload of current had nothing to do with your problems. If your leds have a smaller voltage drop, then they could have been blown by the current, but its unlikly that they would have gone immediately when they were hooked up to power.

 

I have no idea the voltage or anything like that, the only thing that came on the package was: 5mm, yellow, and 5000mcd

 

Update: Brad and I have been talking online and we got to the point where I began testing and the LEDs work fine wired in series if there are 6 in each group. Don't know why this works; but it does. To keep the same design I wanted originally, I soldered the LEDs together and molded them into a '2' shape, this keeps the original 3x8 order that I want:


Throughout all this testing I've blown a lot of LEDs so I'm gonna have to order another 50, then I should have this pretty much wrapped up.

I realize the low draw of the LEDs could make my flash rate spaz out, so I'm going to order some 'load resistor kits' from www.superbrightleds.com

Thanks everyone, and especially Brad92SE for all your help!