Electronic – My DIY RGB LED panel powered by 9V battery works but certain colors like blue, white, and purple don’t work


9v rgb led mod

I am able to power on my LED unit here with a 9V battery. I'm using a recharble lithium 9V as well.

I can't figure out why I can't get blue, purple, and white. The only colors I get are red, orange, yellow, and green.

The LED panel is normally used for some lights in a car, 12V DC, but I know that 9V can power everything at a lower brightness.

Any ideas what is going on? I can't change power sources because the mod goes into a collectible figure that only has room for a 9V sized battery.

The LED panel is this.

Best Answer

It is a bit hard to see from the picture, but since each LED has six pins, and knowing that it is meant for 12V supply, it is extremely likely that the LEDs might be arranged so that there are three parallel chains of three LEDs in series.

The blue LED requires approximately slightly more than 3V voltage drop per LED, and since there is 3 in series, the three blue LEDs require slightly more than about 9V to work. A 12V supply with small series resistance and transistor to drive them would work.

So basically, the LED board is meant to operate with 12V supply, and it can't work with a 9V supply.