LED trouble

[epcIII]

Hi Guys--I saw the LEDs that some of the genvibe members put in their cup holders (great idea), so I tried it too. I put a total of 7 LEDs in--1 in each cup holder, 1 in the bin under the armrest, 1 in the small holder behind the cup ones, and 3 in the front bin. I used the LEDs from PepBoys (that come in the package of 3--like Keithvibe used: http://forums.genvibe.com/zerothread?id=35744), and the rest were from RadioShack (http://www.radioshack.com/product/index ... Id=2062568).Ok now the problem: I put in a switch (http://www.radioshack.com/product/index ... Id=2062493) and connected all the LEDs to it but it starts to feel hot after a minute or so. I haven't driven the car more than 20min. since I put them in, but I'm afraid to leave them on for too long. Is 7 LEDs too much for the one switch, or do they always warm up? I really don't know diddly squat about electronics, but would appreciate any advice.Oh, I t-tapped the wires in the consoles cig. lighter for power. It looks really cool--I just don't want to blow up my car lol. Thanks. I'll post pics when I can borrow a camera.

[tribalman]

did you use a resistor at all? how many Ohms? did you wire the LEDs in parallel or series?

[Wolfman213]

I would recommend wiring the indivual ones separate from the PepBoys ones since they are most likely already resistored and essentially PnP. Use this calculator LED Series Calculator do determine which resistor to wire in series with your other individual LEDs. The desired LED Current is 15mA from what your link shows. The forward voltage drop is averaged at 2.3V, however your link does not provide that actual information, this is derived from a typical voltage for a red led.

[epcIII]

I connected all the positives together and then ran a wire from that to the switch, and had all the negatives together and running to the ground--so I think that is parallel? I was just reading you don't want to do that with LEDs I guess. All the leds came pre-wired with resistors in the (+) wires. The pepboys leds didn't come with any instructions (they were suppose to be in the package but weren't), and I was too anxious to get it done that I didn't research it like I should have--not the best plan.

[epcIII]

I believe the pepboy leds have a resistor built in already, and the radioshack leds have built in 1/4W (?), 680-ohm resisitors built in. I believe I wired them parallel--I connected all the positives together and ran I wire from that to the switch. The switch has a built in led but the package doesn't give any info. except that it is rated at 12A at 12 VAC.

[epcIII]

Sorry- I basically double posted there. Do you think it would just be best to use all the same type of leds, and run them in a series? Thanks for the suggestions and help.

[tribalman]

yeah, you are running them in parallel. you need to do one of a few things, either get a bigger switch, or run a few of them in series. but, because you are going to run a few of them in series and they each have a resistor they might not light up if you string 3, or maybe 2 of them, together.the reason the switch is heating up is because you are running 12 volts across each LED towards the switch, and since it is rated for 12 volts it is now acting like a resistor. not a good thing.

[epcIII]

Dang it, I totally forgot to say thanks for the suggestions/help! I got it figured out, but I don't remember now exactly how I dit it(it's been awhile)--I think I ended running them in series. Thanks again for the info!