26 - 28 Leds Off 12v..., Is this ok? Options

[makaveli91]

I'm about to do a case mod that involves anywhere from 26 - 30 leds. I was told that i could just run them all off of the 12v wire with no resistors and it would illuminate them fine... I was wondering if i could maybe get some opinions or anything that could direct me correctly.. Thanks ahead.

[GeToChKn]

Most LED's, 12v will fry them in a second without a resistor. Hooking them up in series, you can only really hook up 3-4 at a time depending on their voltage usage (for series, you add them together 3v+3v+3v+3v=12v) Mind you, that is per set. You could have multiple sets running. I would go for the 5v power. Since most LED's are 3.3V-3.5V, its a lot less of a step down from 5v to ~3v than from 12V. I either use the 5V line and do each light as a seperate line with a seperate resistor or wire them in parallel although I prefer the first way. That way, each light has it's own resistor and can also be changed or worked on easily.

Click HERE for a resistor calculator that may explain some of it. But the resistors, if you're already ordering lights, they are like 5 cents a piece and will get your lights the exact voltage they need.

[makaveli91]

What i'm looking to do is light up basically 9 jewels... I have circles cut out with windows, each window smaller than the next.. And i was told to do was use the 12v line, and have the parallell circuits in series with eachother.... Does that make sense?

[jeeproject]

[makaveli91]

Yeah, its basically just the jewel, with 2 circles on each leg of the X, making an X of windows. I was going to rig it like i would the led jewel mod, just less leds..

[sp3cialk]

[jeeproject]

oic it all makes sense now.

[makaveli91]

so do u think making the 8 parallel circuits in series, connected to the 12v line with no resistor will work? There is at least 2 leds with a max of 4 (not including the jewel which will have 6)

[vona_a]

Do yourself the favour, spend the 5c and get some resistors !!

Even on the 12V line, hook them up in sets of 3, and calculate how much of a resistor is needed (for the 3V or so remaining).... its safer using even a small resistor than going without one at all.

[makaveli91]

ok, i thought it was a little odd when the guy that was trying to explain this said not to use a resistor.. Thats why i asked again.. And i got a good answer.. Thanks guys for the help