So here's the ? I need to run 22 LEDs for a project I'm working on. The LEDs are 3.4v typical and 3.8 max, 20ma, 40kmcd. All 22 exceed input voltage so that's not going to happen. Using max voltage with 4 in series puts me at 15.3v. So if I run 4 no risistor needed?? If I hook 4 up to the battery the light and don't burn up. I don't want to have to open the lenses back up or burn up these expensive LEDs, so any and all help would be greatly apreciated. I know there are some very experinced led guys on here. OLT comes right to mind.

 

Run them all parallel, if you do it in series, they will burn out and like a set of christmas tree light, one blows, they all go out. Run them parallel with a single resistor and call it a day. Resistors are cheap

 

That crossed my mind. The only reason I wanted to go series parallel, breaking them down into circuits of 4, was due to space. This isn't on a pcb board but the light housing to make the projector glow when not on. But the more I think about it that might be the only way

 

resistors are cheap but take lots of work to weld every resistor to every led bulb!

i just wiring 4 led in series and another 4 led in series to skip the resistor.