Originally Posted by Maverickxeo
Wattage is just how much power they use (I believe; Im not good on the 'technical' terms
What you want to look at is lumens. The wattage plays a role in how bright the lights are, but the more important thing is actually the housing and how it reflects the light.
Mostly correct. I'll elaborate.
An LED can perform very well or very poor depending how the light is focused. Most manufacturers rate LED bars by lumens b/c LED's are stupid bright, and have extremely low wattage relative to halogen bulbs. The lumen number is the total output of light from the bulb in every direction. Only a fraction of the intensity actually reaches any specific surface.
There's two problem with Lumens.
#1 is the advertised number is usually derived with math, and not an actual test. If your bar has high quality bulbs like Cree, probably not a big deal. If it's a flEaBAY Chinese jobber, the number is probably exaggerated.
#2 Lumens tells us nothing about how well a light bar focuses it's plethora of LED's. You can end up with 2000 Lumens being scattered over a 170 degree angle. Or you could end up with 2000 Lumens focused in a 10 degree pencil beam.
Lux is a better measurement, but requires more effort to find and understand. I doubt most manufacturers even bother with it. Lux measures lumens per area (1 Lux = 1 Lumen per square meter). Think of it as light density. A higher number means more light is reaching where you are measuring.
For lux to be meaningful, you need to know the brightness you want at a given range. Probably more specific than 99% of enthusiasts care about.
When you get down to it, lumens and beam angles are about all you have to look at unless you interrogate the manufacturer.