LED Strip Power Supply Math

Thread Starter

JohnJack

Joined Nov 23, 2017
1
I got an LED Strip which runs at 5 V DC and 43.2 watts / meter.

IMG_0382.JPG
This means we have a current of 43.2 w/m / 5 v = 8.64 A / m

Since I have 144 addressable LED triplets per meter a single one requires 8.64 / 144 = 0.06 amps.
My power supply supplies 5 V / 2.1 Amps therefore I can run a maximum of 35 (2.1 / 0.06) LEDs at a time.
IMG_0386.JPG
Can someone please double check if I read the labels correctly and if my math works out? Currently I only work with 30 LEDs at 50% of the brightness but what would happen if I try to draw more current from a psu than it can deliver. Would the leds just not be as bright or does it eventually/immediately hurt my components?
 

pumpkin king

Joined Jan 22, 2016
8
Your LED will start to dim the more LEDs are lit once its starts to draw the full 2.1 amps from your PSU.
I've had similar LED strip lights from ebay and they don't take the current specified in the description, the apparently 43.2w/m are usually fake, it just a selling gimmick to make the LED seem more powerful and a better buy.
Lets say if you did power 1 meter of LED's, you will probably find it only take half the power - aprox 20w/m or 4 amps or even less.
And don't worry, the components will be fine, only time they will suffer is if you supply around 15v or more which I suspect you will never do.
 
Top