310 lumens using 3AAA batteries?

I was in a local tactical shop on my way home today and they were selling this light...

http://www.nebotools.com/prod_details.php?id=193&cid=16

A Nebo tactical flashlight that claims 310 lumens for 2 hours (FL1 Standard). The light was extremely cool looking and used a dial to switch between modes. The focus seemed to work well also. But is this kind of output even possible using 3AAA cells? Could this light have some sort of boost circuit built into it? Nebo's web page shows no sign of the light being regulated. This place takes trade-ins on knives, lights, etc, so I may go by there tomorrow and make a deal with some stuff I have lying around that I do not use! I know this brand is not looked at very highly here, but all I am really interested in hearing about is its output and runtime claims.

nebo as far as i have heard around here is not reliable with their lumen claims, and its $50 bucks, i guess you can give it a try, and even if it does 310 lumen, i don't feel like it would have any good battery life

The FL1 standard measures runtime to 10% of initial output. Because of this, it's easy to claim long runtimes with cheap poorly regulated lights. If they start at 310 lumens and drop steadily for 2 hours to 31 lumens, the average out put is only 170 lumens but they can claim "310 lumens, 2 hours runtime".

Yamabushi said:

The FL1 standard measures runtime to 10% of initial output. Because of this, it's easy to claim long runtimes with cheap poorly regulated lights. If they start at 310 lumens and drop steadily for 2 hours to 31 lumens, the average out put is only 170 lumens but they can claim "310 lumens, 2 hours runtime".

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How would using NIMH AAA's affect this?

NiMH AAA's top out at about 1000mAh for the high capacity ones. Say they aren't top shelf, maybe 800mAh ones of good quality, you could have about 3.6v at 800mAh. If you were to drive an xp-g2, or XM-L (something fairly efficient) you could get to 310 lumens reasonably easily with a decent driver, and without taking the cells past 2.5C discharge rate. It would get hot, and need to step down fairly quickly. Alkalines I would say not likely to get up that high safely or efficiently.

My guess, if they do hit 310 lumens, is that it is for maybe the first minute, then drops rapidly as the voltage sags. 800mAh, direct drive, won't get you very far, and at 2 hours, I would say it has been around 30 lumens for a good hour and a half at least.

NIMH AAAs would have a marginal improvement, but the improvement would only pertain to a relatively steady working voltage as opposed to a dramatic voltage sag. However, it simply prolongs the batteries to the torture of the circuit in its attempt to pull a big amount of current from them to feed the led/UI driver.

I agree with Yamabushi on the rating "scam," but furthermore, even with an ANSI rating, that is usually calculated as bulb lumens... a big difference against OTF [out the front] lumens. A 100 emitter lumen light with a 70% efficient optic can be marketed as an 100 lumen light and it would be perfectly honest for them to do so. Its just a matter of Caveat Emptor.

I bought a light last year that looked good - 2AA, XP-E, 180 lumens max with three modes. Even with L91s it maybe did 80 lumens, and had a horrible PWM on the lower modes. It wasn't cheap either, cost $30.

I gifted it to a friend and they think it's awesome. Which was timely as they had a six hour blackout not many nights later.

Thanks everybody! I thought with these new FL1/ANSI standard ratings , that the days of misleading lumen ratings were gone, looks like I am wrong! All the lights that I have bought lately. however, with those ratings, have been pretty spot on. This place takes in stuff for cash or trade in. If I can get this thing for $20.00 or less with a trade in, I am going to pick it up. It would be worth that much I believe!

mikekoz said:

Thanks everybody! I thought with these new FL1/ANSI standard ratings , that the days of misleading lumen ratings were gone, looks like I am wrong! All the lights that I have bought lately. however, with those ratings, have been pretty spot on. This place takes in stuff for cash or trade in. If I can get this thing for $20.00 or less with a trade in, I am going to pick it up. It would be worth that much I believe!

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When the ANSI/FL1 standard was introduced, there were plenty of complaints about it on CPF. I do not like that three samples are selected by the manufacturer to be tested, nor that runtime is counted until 10% of initial output. I could design a driver circuit that would give the stated rating of 310 lumens for 3 hours, by driving it at 310 lumens for two minutes and then dropping to 50 lumens. At least it's something, though - and there are worse manufacturers (100 lumens for 5 hours on one AAA being the worst offender).

I was actually able to get one of these lights (and a 250 lumen Nebo) without spending any of my hard earned cash! All of you that commented about its runtime pretty much hit the nail on the head! Last night I put in 3 charged 850mah NIMH cells in it and turned it on at 8PM. You could not make out any change in brightness until it was on about 20-30 minutes. After that it slowly dimmed. It was still running at 11:00 and it was bright enough to guide me up the stairs to bed. I still like the light and it was worth what I traded it for!

mikekoz said:

I was actually able to get one of these lights (and a 250 lumen Nebo) without spending any of my hard earned cash! All of you that commented about its runtime pretty much hit the nail on the head! Last night I put in 3 charged 850mah NIMH cells in it and turned it on at 8PM. You could not make out any change in brightness until it was on about 20-30 minutes. After that it slowly dimmed. It was still running at 11:00 and it was bright enough to guide me up the stairs to bed. I still like the light and it was worth what I traded it for!

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Now try an 18500 LiFePO4 cell. I have had good luck with these as a direct-replacement for AAA cells. Wal Mart sometimes stocks them in the 'solar lights' section. They're on clearance here.

Just looked those up. They seem to be low capacity like the AAA's (650-800mah) and lower voltage (3.2v). Would they really give better runtimes?

mikekoz said:

Just looked those up. They seem to be low capacity like the AAA's (650-800mah) and lower voltage (3.2v). Would they really give better runtimes?

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AAAs do not hold their voltage under heavy drain, while LiFePO4s do. An alkaleak will drop to about 1.0v per cell when drawn at half its capacity (500 mAh out of a AAA is plenty to do this), and NiMHs at 1.5-2C (for small cells, 800 mA). That gives you a hard current limit.