Lumens = Total light output

 

Candlepower = Light intensity or brightness

 

Though related, they measure different qualities of the light source; it takes more parameters than a fixed conversion factor to relate them.  The links that recommend a conversion factor of 12.57 are wrong.

 

You can change the intensity (candlepower) of a light source independently of the light output (lumens) by adjusting the focus of the beam.  In motor vehicles, this could be analogous to relating horsepower and top speed.

 

Taken to an extreme, a laser pointer could have very high candlepower/intensity (higher than your Q-Beam), but would be a poor choice for illuminating the path ahead because it doesn’t actually produce much light (and the light it does produce is narrowly focused).

 

As a gut check on top of this, think about how fast 18,000+ flashlights would drain your battery.... That energy has to come from somewhere.

 

Edit:  FWIW, the 12.57 conversion factor assumes a conceptual light source which emits a uniform intensity of light in all directions. If such a source emitted light at a uniform intensity of 1 candlepower, its total light output would be 4π lumens (4*3.142 = 12.57).  

 

In the case of the Q-Beam, the light is focussed and the candlepower rating will be based on the peak light intensity at the center of the beam, to give the most impressive number.  If this peak intensity was produced uniformly in all directions, the total output in lumens would indeed be through the roof, and it would be an extraordinarily bright light that you wouldn’t want on your boat.

Edit; posted at the same time as fissure_man

 

meant no disrespect with the trolling comment

This thread has taken a strange twist, we are now studying light physics..lol

 

Slow down, don't blind others, assume somebody is out in front of you. Get home safe.

Common sense, would you want a bright light shined in your eyes while driving down the lake at night.....no! Would you see another boat coming down the lake a long way off with a bright spot light shining on the water.....yes!

It takes time to recover from night blindness from a bright light in your eyes, you are blind for a few seconds.

Tom

@Arcs&sparks chill out! 

 

I was fishing for @Sam but he wasn't biting & you aint fun!

All I know is that I am going to Wally World to buy

a really, really, great.....best in the world, 1 billion candle-power QRSTU Beam spot light, to ensure satellites can see me from Mars.....

I just quit fishing when it gets dark and idle back to the ramp. I still hit logs all the time while idling

80% of the tournaments I fish are night tourneys. We start in daylight hours but end between 4 or 5am. We run 50-60mph at night, even faster if we need to get back fast. The river channel is 60-140ft deep depending on the lake we’re fishing.  If there’s been rain or we notice any logs or trash on our way out we move slower than normal back to the dock. We use our Q-Beam to check for floating objects. If we see a boat it gets a couple flashes in the air. There’s plenty of room for boats to travel. Our lakes are typically clean of debris. The only real danger is a dock or boat that’s came untied and floated out. We’re constantly checking. Teamwork is the key to night running like @catt said.