Hello

I connected at the 12 V sockets from diffrent trucks a flexible led strip smd of 50 cm.

The problem is that at some cars the led strip burned out (only a few leds were on and they barely had luminosity).

I want to mount in my truck a led strip with one color and connect it with a led strip which has 2 colors (half white , half red).

I attached some pictures where you can see how the led strip burned out (the smd leds cracked) and a picture with the led controler i used to modify the light intensity.

What can i do to protect the led strip ? Is the voltage a problem?


Link controlor led strip
https://www.aliexpress.com/item/Dim..._1&btsid=46132328-7a64-473a-b257-6998cb251ca1

 

I can't help with your question, I am not familiar with these LED strips.
On your controller picture you have marked a resistor '263 26kΩ' but you have read this upside down it is actually '392' - a 3.9kΩ resistor.

 

Yes , you are right is a 3.9kΩ resistor.

 

Some cars, like Ford for example have an "intelligent" alternator that kicks out around 15.5v (14.4 is normal in a running 12v system) to fast charge the battery. It's known to have the effect of blowing headlights bulbs on a regular basis.

You mentioned "trucks" though, most "trucks" and larger commercial vehicles run 24v systems. This does depend on your definition of "truck" though.

 

The biggest problem you are dealing with is simply very poor light strip design being used in the wrong environment it was never intended for.

I see in the one picture the main resistor is a '390' or 39 ohm ~.25 watt unit of which if its in series with 4 white LEDS with a nominal forward voltage drop of 3 volts each at a 13 volt input it would be seeing a 26+ mA current which equates to a ~.026 watt thermal load on it and at a high 15.5 volt (smart alternator limit) that would be a 89 mA and .3+ watt thermal load on it which is way past that size of surface mount resistors capacity.


I'm suspecting that those LED light strips were designed to run of of 12 volt regulated power supplies and not a standard automotive electrical systems that in reality normally operate at 14 -15 volts when the engine is running.

That's why they blow themselves up.