Phillips T10 LED bulbs flickering at lower voltages

I am using these bulbs for interior lighting in a RV.

Philips 129644000KX2 XtremeVision 12V T10 LED Interior/Exterior Retrofit Bulb

I have noticed when my battery voltage drops to 12.2 volts, that this is when the t10 bulb starts flickering. Not on and off, but changing brightness levels very rapidly. My laptop feeds on the same 8 foot 10 AWG power distribution circuit that also powers this rapidly flickering LED. When I unplug the laptop, taking an ~ 75 watt load off the circuit, the light stops flickering.
I just measured the voltage near the flickering light and it is 11.42v. The light itself is about 3 feet further away over 22 awg zip wire. My clamp on meter says it is drawing between 0.03 and 0.04 amps, but I do not trust it at these very low currents.

This is the only name brand LED I employ, and the only one which flickers. The others I employ just get dimmer until about 5 or 8 volts then shut off. ( tested with a buck converter, I do not take my batteries that low) This Phillips LED does respond nicely to a PWM dimmer, so do most of my others. The few that do not respond to the dimmer, just shut off when dialing them down to ~ 60%.

I know the solution is to reduce voltage drop on the circuit. Or run the bulb on a different circuit, but I am curious as to why this name brand LED bulb is so sensitive to voltage input. I have a Cree based LED fed by the same distribution point, and it never flickers.

I did a consumption test on the dc to dc adapter feeding this laptop with my clamp on DC ammeter, and found that the numbers were jumping all between 5.94 amps to 6.86 amps with a depleted and charging laptop battery with laptop on. I wonder if the actual laptop is so rapidly changing its power demands that it is directly responsible for the flickering.

I know this is subjective with more than some room for error, but my Cree based bulbs produce ~twice the light at 3x to 4x the wattage consumption compared to the T10 Phillips.

I guess there is no real question here. I know the problem and the resolution, I am curious as to why it is occurring, and if this flickering is detrimental to bulb life.

Comments?

wrcsixeight said:

I did a consumption test on the dc to dc adapter feeding this laptop with my clamp on DC ammeter, and found that the numbers were jumping all between 5.94 amps to 6.86 amps with a depleted and charging laptop battery with laptop on. I wonder if the actual laptop is so rapidly changing its power demands that it is directly responsible for the flickering.

Click to expand...

Try a stable load on that same circuit, like an auto headlamp or two to try to get the same 72.5-to-84W load-- then try dis/reconnecting one of them to change the load quickly.

The laptop may also be sending back EMF whenever it's adjusting its load.

A steady load on that circuit after my post last night, did not cause the flickering. I even tried a 16 amp air compressor to really lower the voltage on the circuit, but it did not flicker, it was just dimmer.

What is strange is that I cannot get the bulb to flicker again replicating the conditions where it flickered yesterday. my Clamp on ammeter is still jumping around on the dc to dc laptop power converter. Drawing the same current, same voltages. hmmmm.