Maglite 3D and 2AA

I would check out Brock's Website: http://www.uwgb.edu/nevermab/flash.htm

The chart at the bottom shoud answer many of your questions. This chart is the flashlight bible (IMHO). I refer to it almost daily. Great work. Please expand it

15 Lum per watt is a VERY rough conversion for high power lights

For example:
M6: 30 watts * 15 lum/watt = 450 lum
SF spec = 500 lum

12 Lum per watt is a VERY rough conversion for low power lights
P60: 5.3 watts * 12 lum/watt = 63.6 lum
SF spec = 65 lum

So, a 3D Mag is a low power light
3.1 watts * 12 lum/watt = 37 lum
(Brock, is 3.1 with STD or Carley bulb?)

and a 2AA mag is a very low power light. I will guess that it is 10 lum/watt

Std bulb: .85W * 10 lum/W = 8.5 lum
Nextstar: 1.25W * 10 lum/W = 12.5 Lum

Before some CPF members freak out, I know this method of Lumen calc is flawed. It is too simple of a model. But, if you know of a better method, I'm all ears. I would guess the mags are less efficient than the SF's.

I guess Lm/W depends on the bulb quality. For example: The DB 620 has a 2.9W xenon/halogen bulb and 54 lumens output. That means 1W = 18 lumens.

Brock's table is great, but i miss the flashlight's run/burn time.

According to the info on brightguy.com the 2AA light runtime is 6 hours and the 3D light is 14 hours.

I need info about Maglite 3D and 2AA

What's the run time on both?
What's the lumen output on both
What's the amount of wattage on 2AA?

Thanks

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by recercare:
I guess Lm/W depends on the bulb quality. For example: The DB 620 has a 2.9W xenon/halogen bulb and 54 lumens output. That means 1W = 18 lumens.<HR></BLOCKQUOTE>

The data for the T2-X bulbs is overstated. A well known person measured it and it turned out to be significantly lower. These bulbs are in the 10-12lm/W range.
A small bulb (= no halogen) like the MiniMag's will be in the 6-8lm/W range.

Anyway, the luminous efficiency depends much more on the filaments lifetime than on the bulb's quality. You may drive a bulb in way that it lasts 3000 hours or 10 hours. Difference in efficiency may be 1:2.

And for quality: A good quality 12V 35W GE halogen bulb will have some 16-18lm/W at 3000 hours lifetime. The better Osram have ~22lm/W.

But people who connect bulbs with alkaline cells without any regulation do not care about efficiency anyway, so why bother ? .-)

30-36 lumens for the DB 620 is probably right. I have a 100 lumen Sigma Mirage, which is more than double as bright, probably three times brighter.

PeLu: What do you think would be most correct for the Maglite 3D? ...10Lm/W?

You have all been a great help, thank you

Yes, the 3 cell Mag has a "standard" Mag lamp in it.

I wish I could put runtimes on my site, but where do I put the cut off for useful light? I thought about timing it to 3/4 of original light output. Maybe just figure it from battery capacity in a generic form for each light?

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Brock:
I wish I could put runtimes on my site, but where do I put the cut off for useful light? I thought about timing it to 3/4 of original light output.<HR></BLOCKQUOTE>

What is original light output? Initial brightness with completely fresh cells?
Then, for example with AA alkaline cells and a 0.5A bulb you will have this state after about 5 minutes (compared with more than 2.5 hours until zero).
Or you take the bulb's nominal voltage and look when it will be down to 3/4 of this 'nominal brightness'. Then you will get ~23 minutes.
With D cells it may be even worse.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>
Maybe just figure it from battery capacity in a generic form for each light?<HR></BLOCKQUOTE>

Taking nominal cell capacity divided by nominal bulb current?
This will give you 5.5 hours for the example above.
There is no other way as to try it and to give the ntime down to 3/4, 1/2, 1/4 brightness and so on.

OK, we are coming back to my idea of a (physical) battery simulator...

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by recercare:
PeLu: What do you think would be most correct for the Maglite 3D? ...10Lm/W?
<HR></BLOCKQUOTE>

I don't have any here, but for a good halogen bulb of 3-5W 12lm/w should be OK. But don't forget: That's true only for the nominal voltage!
In practical life and giving a tolerance width of 10% (for the brightness), you will only have 3% of total runtime inside this treshold.