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-   -   Benny's first DIY : LEDs on an Ikon (https://www.team-bhp.com/forum/diy-do-yourself/50723-bennys-first-diy-leds-ikon-3.html)

3 blue LED's means 3*3.7V which is approximately 11.1V. The car provides 12V to the bulbs.

I'm not sure how much current these can handle. You may need the current limiting resistor.

Nopes, thats not even an option. ;)

Get her to watch FnF. :D

Would LEDs generate so much of heat? I doubt it. Someone please correct me, if wrong. I havent left the cabin light on for long durations, as i have the switch placed at the door open position.

I was advised to use a limiting resistor, but decided to just try it out this way. Lemme see.

Been really busy with work that it leaves little time to fiddle with this for the time being.

Yes they can produce heat before burning off. That is exactly why i keep stressing to use a resistor.

Please dont do LED circuits without resistors because by getting the LEDs over nominal current you make them overheat and rob them their extraordinarily long lives. A 20mA LED working at 50mA will be giving out slightly below double its normal light emission (the overheating makes it far less efficient), but it will only live between 100 and 500 hours (4 to 20 days), contrary to its theoretical mean life of 50,000 hours (5.7years).

Just curious. How would you connect the resistor? Parallel to the LEDs or in series?

i connected the resistor in series with the LEDs(in my DIYs). But parallel connection can also be done.

Now that badboyscad has spoken with reason, i will do accordingly.
The other problem for me is that in order to buy a resistor of a different rating, i will need to go all the way to SP Road. :Frustrati

OT : Do any of the Bangy guys know a place which sells these electronic items near Marathalli?

Folks, it is a bit more complex than that.

First of all you need to connect a resistor in series to the LEDs. Job of the resistor is obviously to bring down the current to the optimum operating current rating for the LED.

For any electrical circuit, OHM's low is applicable, which says

I = V/R

where I is current, V is potential in Volts and R is resistance.

Unfortunately, in a LED, the rule doesn't apply, and LEDs doesn't seem to offer any real resistance. So, bottomline is, any variation in Voltage could bring an exponential variation is current (unlike Ohm's law) if LED alone is connected across the potential. In Car batteries, Voltage does vary.

Here is a good source to calculate the Ohms for the resistor.

You mean a resistor parallel to LED ?

best way to connect is a resistor for each led in series to it and put them together for maximum life. going series with all leds powered by a single resistor is not recommended by experts, but i know it makes the whole thing whole complex. did you keep the lights on for sometime with the engine running, quite possible they will fail in a day or two. my experience.

Nopes, i have had the lights turned on with the engine running, but not for prolonged durations.

I tried out an arrangement this evening using white LEDs in series.
I connected the 3 white LEDs in series with a 47 ohms resistor. Didnt click any pics as this was a crude arrangement as well. Will try and get a PCB this weekend and fabricate a better set-up.

no no. use 82ohm 1/4 watt resistor for white LEDs.

But in my experience R=V/I works very well where V=Voltage drop across the resistor and I = working current of the LED.

If we connect a LED of 3v with 20mA of nominal current across a 12 Volt source then the Value of the resistor should be (12-3)/0.02 = 450ohms with 1/4watts.

Also I think the voltage may vary between 11.5-12.5 or 13.0 I believe depending on the battery and alternator output.

Benny, that's a neat and sweet job. It does look cool. Does it feel cool too :)

About the resistor and LED. Yes, its always suggested that they should go both hand in hand. Do not separate them and make any sin. Lol.

That would be interesting. What colour do you think will look good on the console, considering yours is front lit ?