4/14/2022

A few of the interior light bulbs in my car burnt out so I wanted to replace them. The original bulbs work on outdated technology called incandescent, which is much less efficient than LED technology.

I hopped on scamazon and searched for interior LED car bulbs to see what Jeff Benzos was offering up. I compared several brands and was annoyed that every brand says theirs bulbs are 400% brighter than the rest, and why the other styles are inferior. They are also priced similarly, but all have different coupons automatically applied at checkout so you have to do a bunch of math to know what you actually pay.

Since I’m an engineer working in the LED lighting industry, I have far more knowledge and access to equipment than most people do so I knew I had to do one of those “which brand is best” comparisons.

My fog lights also needed replacing so I decided to get a couple of those as well.

The interior lights are these small little ones and they are called “158” style or shape light bulbs. The fog lights are the bigger L shaped ones and are called “H11” bulbs.

What I did was put each bulb into a machine called an “Integrating sphere”. The sphere measures the light from the bulb. It displays results that can precisely differentiate small differences in brightness, color, and efficiency.

Some of the bulbs can operate at 12 volts and 24 volts, or some can change color, I tried to test all the options I could. I show my data below along with a brief description of some of the words

I ultimately chose to keep the Auxito brand bulbs. It was a hard choice between those and the Yorkims. On one hand, the Yorkim cost the least, and they are the most efficient. On the other hand, the Auxito are almost twice as bright, and still use less power overall than my current bulbs.

  • In general LEDs run more efficiently (Flux/W) when they are driven at a lower current. More casually put, a lot of smaller LEDs is more efficient than a few bigger LEDs.
    • Novsight only uses 4 LEDs and has the worst efficiency despite also producing the least light. Those 4 LEDs are all essentially working too hard.
    • Yorkim/Marsauto Use 5 LED packages, but there are really 3 LEDs in each package so 15 LEDs. These have the highest efficiency. All these LEDs are working close to their optimal rate.
    • Auxito Uses 24 small LEDs, but how come the efficiency is less than the Yokim? Im guessing that those small LEDs are being pushed too hard, and out of their optimal rate. They put out a total of 52.5 (127.5-75) more lumens than the Yorkim. I bet if i dimmed the Auxito down to put out the same Flux(75.5 Lumens), then the auxito would run more efficiently.
    • UPDATE: I tested the Auxito bulb at 75.5 lumens. Surprisingly, it had the same efficiancy as when it ran at 128 lumens. I was wrong about it becoming more efficient as it dimmed. There must be a more complicated IC or control circuit than i realized.
  • It is incredible how inefficient the incandescent bulbs are. Less than 5 lumens/watt.
    • That means even the least efficient LED(Novsight), is still almost 10x more efficient than incandescent.
    • In general, LEDs have become affordable enough to warrant that the average consumer should use LED vs Incandescent whenever possible. This includes, work lighting, car lighting, home lighting, Christmas lights, restaurant.
  • Also note that all of the LED bulbs use less wattage than the incandescents.
    • This means that no matter which LED i choose, i will still use less energy than the old style AND it will be brighter.

Of all the lights, I wanted these door lights to be the brightest. The old bulbs were not bright enough to light up the ground of where i would get out of the car. Because of that, I have stepped into water and mud while getting out. Look how well illuminated the ground is now 🙂
Here is the new fog light.