Hi guys, I’m attempting to mod my first flashlight and I’ve got a quick question for you about the wiring of a 12v led bulb I got from banggood. There are 4 leds. Two of the LEDs have their positves connected together and two have their negatives connected together. The remainder are connected positive to negative. This is series parallel wiring correct? I am assuming that these are 12v leds. I tested them with 4.5 volts and only 2 lit up. With 12v from an old cordless drill they screamed and I quickly shut them down. I’d like to replace these 12v leds and I believe in the configuration they are wired in I’d be good to go replacing them with some 3-3.9v emitters from fasttech. This is for a drop-in replacement for a mag from this thread. Any suggestions on an emitter? I’m open to swapping out my 2D cells to 18650’s and using a driver. I’d like to get a nice big spill. Here’s a picture of the bulb which will be the basis for my mod:
so each of the two LEDs turn on at about 4.5/2 but I guess it could be as unbalanced as 1.5v/3v. The datasheets don’t much tell you this info.
Which two turned on? This will give info about the two that didn’t light.
At ~6v each they are hard on and probably have already used up a considerable chunk of their life.
If you don’t want to use a resistor in series with your voltage source at least use a fuse.
For a max 1A LED current and a DC voltage source of V volts your resistor should be >V/1 ohms and ~Vx1 watts.
The two that have their negative terminals wired together turn on, very dimly.