Electric GURU assistance requires. I got an Led Strip with 12 LED light on it.

I want to connect this up to the fog lights connectors which arnt being used as i have no fog lights but when i last did this my leds started blowing slowly till they stopped working altogether.

What do i need to do to connect the power and earth of the LED strip to the fog lights without them blowing? Do i need to use an inverter?

thanks

 

I'm not an electrical guru but...
Pretty sure the headlights are DC? So you wouldn't want an inverter... since an LED is a diode which means it will only accept current in one direction. Which means you want DC anyway.
How long did your LEDs last last time? Without any resistors they will overheat.
To find what kind of resistors you want you'll need to know what voltage and current your LEDs run at.

 

standard 12v im guessing

 

a led globe on its own only will take 2-3v across it. more and they will blow.
but im assuming in your case its a pre packaged led strip that usually run on 12v.
they should not blow unless its getting too much power, or possibly too much vibration?
how long did it last? and have you tried another one? mabey you were just unlucky and got a dud?

 

Oh didn't read properly, they are LED strips... Maybe you'll need a 12V regulator? I think the car outputs upto 14V which may be overheating the LEDs. Sorry I don't know how your strip works unless I can see it.. perhaps someone who has worked with these can give their input

 

both blew and lasted a few weeks if that. And yes im talking about these ones.

Someone told me i might have got the polarities wrong when connecting to the fog light connector? can this happen and im pretty sure black wire is earth on the nissan. So these LED's are 12V, what is the fog light connector voltage?

thanks

 

if polarity on a led globe or tube is wrong they just wont work.
they usually dont cause damage.
being diodes they only pass voltage one way

 

Looks like crap quality. You can't connect them wrong, and voltage is fine.

 

So these ones: LED STRIPS should work fine just connecting them up to the 14V fog light connectors even though the strips say 12v? hmm

 

You could really write a book on this.

A typical LED has a forward voltage of 1.8-2.0V and needs a current limiting resistor to stop them blowing up. If the operating current needs to be limited to 20mA (which is typical) that resistor would be 560 ohms for a 12V system. The usual way to manufacture this thing would be to parallel connect all the diodes internally, each with its own 560 ohm resistor. If one unit failed, the other 11 would keep going.

At 14V the right answer for the resistor would be 600 ohms, or to put that another way, if you put 14V up to the strip using 560 ohm resistors, the increased current would be less than 22mA, which couldn't possibly be outside the operating tolerances of the LEDs. You couldn't possibly have to resort to using a regulated power supply for such a trivial appliance.

So something else is going on here. If all of the LEDs go out at the same time, I would suggest a broken connection inside the unit maybe due to vibration, or simply poor quality manufacture. Did you mount them securely? If the strip was flapping around that would do it.

 

I had different LEDs before, not these strip ones. And yes they one by one until all 24 were gone over a couple of months. So what should I do angrybear. No vibrating apart from the normal car headlights on the car. Just as stable.

 

So youve tried 2 different sets and they keep blowing?
is there a change the altenator is on its way out and slightly over charging?
have you got a multimeter/volt meter to check the running voltage isnt too high?

 

As they said when I was in the miltary all those years ago - never volunteer.

However, if you send me one of those dead strips, I will do a post mortem on it when I get some time. Please note I am not talking repair here, but a destructive dismantling to see what happened. I will be staggered if there are 12 dead LEDs in there. I seem to recall the MTBF (mean time before failure) of a LED is 100,000 hours.

My money is on 12 dry joints or 12 cracked tracks.

If you want to surrender one of these duds for forensic analysis let me know and I'll PM my address.

 

Darn, i knew i should have kept them. I threw them already mate

Im going to connect these strips up and solder them on to the fog light connector and hope they are better quality. Alternator is fine and always around 14V. I just thought maybe i need to use a resistor or something because the fog lights pump out 14v and all led's are 12v.

cheers

 

As Angrybear has already explained, LED's ARE NOT 12V.

When using LED's it is important to calculate the combined voltage(and amperage)requirements of the particular items so that the total is equal to, or greater than the available power supply. This usually means that resistors will need to be used to protect the LED's.

Maybe the previous failures are an 'Act of God', or intervention by 'The Z32 Good Taste Fairy'?:zlove:

 

And i always

Thought you liked mine.
It was a visit from the Good taste fairy one night that meade me do it.

 

I make allowances for people like you(but not very often).:rofl::rofl:

 

So Chili mate, should i put resistors to them before i connect them up to the fog light wiring? a few posts above iv included the link to the LED's

thanks

 

The value of the resistors you need, is determined by the number and voltage draw of the LED's in each strip and the actual voltage delivered from your wiring loom.

 

The only figure on the led's is 12V. and I have been told the fog light connector transmits 14V.