Connect plus end of the led and negative end to plus and minus terminal respectively of the 12 v car battery. Yes, led lights up and no flickerings at all.

However, when engine is started, the led strips lights up but starts to flicker very fast. If not properly observed at about 3 ft away, the flickerings would not be detected by the eye!!!

The cob strip is 100 percent working fine and no defects at all.

Is the flickerings due to ripples effect from the battery or how to make constant bright with no flickerings???enter image description here

2 Answers 2


When you start the car the starter motor is drawing a lot of power, and you'll get fluctuations in current. LED strips pulse many times per second, too quickly to see, the strips are flickering because during some of the pulses there isn't enough power to light them, so they go momentarily dark.

If you want the LEDs not to flicker when you start the car you'll need to isolate them from power fluctuations by running them off of a separate battery.

  • Not only while starting, the led also flickers throughout the engine is still running!!!! It still flickers as I revs the rpms!! Can it be solve with capacitor connected in parallel? If so, what's the rating??
    – Thang Tons
    Jan 3, 2020 at 8:49
  • The way your question is phrased it seemed to imply that this was during startup. Have you considered that it could just be vibration you are seeing?
    – GdD
    Jan 3, 2020 at 8:53
  • Nope...I reconnected the same led at the output pins of headlamps...and still the same flickerings happening. You could try one at car to verify the exact issues.
    – Thang Tons
    Jan 3, 2020 at 9:11
  • Are these strips specifically made to work with car electrical systems? LED strips need clean power, you'll likely need to run it off of a separate battery as I suggest in my answer.
    – GdD
    Jan 3, 2020 at 9:14

You could have an open diode in your alternator. There are normally 6 inside. So the alternator output is "rough." An LED light has instantaneous response to voltage changes, and so it shows that roughness by flickering. An oscilloscope will display the rough output of the alternator. Try the LED light on another vehicle to be sure it is not the lamp.

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