# 6 volt 35 watt spotlight... How many lumens?



## fire-stick (Jun 27, 2007)

Would anyone care to take a rough guess as to how many lumens my new spotlight is putting out?

It is a 6 volts bulb @ 35 watts.


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## 2000xlt (Jun 27, 2007)

I am not really sure, perhaps if you could divuldge some more info about your light, you may get some more help.


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## fire-stick (Jun 28, 2007)

~2.5" - 3.0" reflector
SLA battery
Halogen bulb 6V, 35W
it's made by brinkmann
it's has an LED low mode


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## TorchBoy (Jun 28, 2007)

Is this a competition or are you just wondering how bright it might be in theory?

I read a thread recently where someone explained that halogens don't run as efficiently on SLAs as they should because the bulbs are designed for the higher voltage provided by car charging systems. I'm not sure how much that also applies to 6V, but based on what he said (including system inefficiencies), I'll take a stab with 500 lumens.


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## winny (Jun 28, 2007)

If you take a look here, you can see that the most efficient 6 V bulb does about 25 lm/W at 100 hours lifetime. Therefor, you can say with a high probability that your bulb produce somewhere between 0-875 lumen. My guess would be 600 bulb lumen, with perhaps 400 of them coming out of the front window.


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## winny (Jun 28, 2007)

TorchBoy said:


> I read a thread recently where someone explained that halogens don't run as efficiently on SLAs as they should because the bulbs are designed for the higher voltage provided by car charging systems.



The bulb have absolutely no idea what kind of battery is on the other end of the cables. What do matters is that some bulbs marked 6 V, 12 V or 24 V are actually rated for 7.2, 14.4 or 28.8 V respectively because thats the charging voltage for normal SLAs. Therefor, when you apply 6.0, 12.0 or 24.0 V, they won't be as bight as they would have been in a typical bike/car/truck.


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## TorchBoy (Jun 28, 2007)

winny said:


> Therefor, when you apply 6.0, 12.0 or 24.0 V, they won't be as bight as they would have been in a typical bike/car/truck.


And for each ~10% drop in voltage there's a ~20% drop in brightness, hence less efficiency. (You might want to suggest some more accurate figures winny.)


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## winny (Jun 28, 2007)

TorchBoy,

Well sure.
If we drop from 7.2 to 6 V we drop 22.5 % power and 45.4 % luminous flux, making it 29.5 % less efficient.


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## f22shift (Jun 28, 2007)

300?

is it one of those million candle spot lights?


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## TorchBoy (Jun 28, 2007)

Is this it?

http://www.amazon.com/dp/B000NUPD0E/?tag=cpf0b6-20


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## 65535 (Jun 29, 2007)

I would say about 3.5 watts of light energy.


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## aerosimon (Jun 29, 2007)

Guess: 35W marked, really probably 20, lead acid usually = underdriven, 15-20L/W: 3-400Bulb Lumens.. Can you please measure current draw

On LED low, less than 3-400 Lumens


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