Run time test - Arc AAA head and 1 D cell

Orion

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I have begun a runtime test of this torch:

fb61cea2.jpg


I am using an older battery, which actually has the January 2001 on it, so it's an old battery.

Anyway, I started it at 10:00 am today (Saturday, Sept. 6th) and will report back how long it took to get too dim to be useful.

Stay tuned if interested at all. /ubbthreads/images/graemlins/icon15.gif
 

Doug Owen

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Cool. Too bad you didn't get a piece of 'magic filter' and the CdS cell:

Poor Man's run time meter

You could be measuring (and hopefully reporting) 'time to half initial light output', IMO a more useful and far less subjective measure.

Anyway, based on an estimated average 200 mA current (240 or so down to 1.3 Volts) and a look at the Energizer run time graph for 200 mA my money's on about 70 hours to half value light (14 of the total 18 Amp Hours available to .8 volts at 25 mA draw). What 'useful light' is, and how long to there I don't know.

So, "about this time Tuesday" is my bet.

Doug Owen
 

jtice

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I have ran mine now for about 40+ hours, I cant really tell a difference in brightness what so ever. /ubbthreads/images/graemlins/thumbsup.gif
 

Orion

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jtice, I'm seeing the same thing with mine. at goining on 47 hours, still seems the same brightness (perceived), as well as side by side test with my Arc AAA.

I remembered that the battery "Best if installed by" date as Jan 2001, so it isn't a new battery being used for this test. It still had 1.5 volts showing on the meter.

I have no light output meter to test what is coming out of the LED, so it is just perceived brightness until it switches to moon mode.
 

Doug Owen

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Running to 'moon mode' is not a very good standard, IMO. It's quite dark by then. FWIW. And the curve is so slow just before then as to defy repeatable runs within I would guess a few hours time, maybe more? Guessing is useless, and it takes a pretty big difference in real levels for our eyes to see, having to do with the log response of our 'detectors'. Evolution equipped us this way to allow us to see effectively over many orders of magnitude, but makes 'A/B tests' very subjective.

Run time to half level can not only be easily measured (I think very easily, see below), but you should be able to estimate it based on cell voltage. At 1.5 Volts, the one's I've checked are about 250 mA (375 mW) of input power. At 1.2 Volts, this is down to 150 mA (180 mW), half the power in. Assuming (and it's a big one) efficiency is still about the same, light level at 1.2 Volts should be half that at 1.5. Measure the cell voltage and you'll know when you're there. This needs to be 'tightened up' by actual measurement of course, but it should be close. Anyone want to do this? Measure your Arc head's light output and current draw for input voltages from 1.0 to 1.5 Volts?

However, I think you're missing a bet if you already have a DMM to measure the meter. I've still got some filters and CdS cells for those that want to experiment with making a simple *light level* measurement to determine accurately the 'half the original light out' point.. All it costs you is a couple envelopes and stamps.....

Poor Man's runtime meter

Doug Owen
 

Orion

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I guess I'm more interested in usable light from this test. As of now, there's no discernable drop in output. But even when there is, if this light is still producing an ample amount of light, then the test will continue. I don't have a light meter and probably don't have the time/ability to make one, so this is a simple test. So far, going on 49 hours, it's still looking good. /ubbthreads/images/graemlins/thumbsup.gif
 

hideo

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might have to try this with my LED Mods ASAP Nichia module which draws a whopping 20 mA in a Solitaire (runs for about 6 hours on a toasted AAA alky) /ubbthreads/images/graemlins/wink.gif

hideo
 

Doug Owen

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[ QUOTE ]
Orion said:
I guess I'm more interested in usable light from this test. As of now, there's no discernable drop in output. But even when there is, if this light is still producing an ample amount of light, then the test will continue. I don't have a light meter and probably don't have the time/ability to make one, so this is a simple test. So far, going on 49 hours, it's still looking good. /ubbthreads/images/graemlins/thumbsup.gif

[/ QUOTE ]

Understood. I'm just saying I think such subjective measures are problematic. And I don't agree that a 'half light level' measurement is costly (under a dollar if you have a DMM), or takes more than a few minutes to set up. Have you read the 'poor man's runtime meter' thread?

My estimate above, 70 hours, to half level, still stands.

Doug Owen
 

Orion

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I did read it, but I don't have much electronics sense to fully understand it, nor to create what you suggested in that thread. I have a multi meter, but the only thing I use if for is checking voltage of batteries. I've never really understood how to do other things with it. I guess I have had a lack of interest/time to study it more.

Anyway, at 72 hours, the light output is still the same, as perceived by me, and when compared to my Arc AAA. I'll keep you all informed.
 

Orion

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Going on 78 hours now, and I *believe* I'm beginning to see that the light from the test torch isn't as bright as the comparison light, my Arc AAA. Since I don't have a way to check the output, it may be that it is heading towards the downward slope out output. The difference isn't much, and the test torch is still plenty bright. Just perhaps not quite as bright as the Arc AAA.

Perhaps this unscientific test is coming to a conclution? /ubbthreads/images/graemlins/icon3.gif
 

Orion

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As of the 85th hour, last night, the output was a bit less than my comparison Arc AAA. When I woke up this morning, though, the output was less than half that of the Arc AAA and the battery was at .5 volts on the multimeter. The test has ended. The "Best if installed by Jan 2001" battery has found a new home in the trash. So, I figure with a new fresh battery, I should get around 85 hours of continuous runtime, perhaps longer, of usable light. I suppose I could do the test again with a newly purchased D cell to see what it would do. Would that be worth doing?
 

Doug Owen

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[ QUOTE ]
Orion said:
I did read it, but I don't have much electronics sense to fully understand it, nor to create what you suggested in that thread. I have a multi meter, but the only thing I use if for is checking voltage of batteries. I've never really understood how to do other things with it. I guess I have had a lack of interest/time to study it more.

Anyway, at 72 hours, the light output is still the same, as perceived by me, and when compared to my Arc AAA. I'll keep you all informed.

[/ QUOTE ]

Cool. Please bear with me:

The idea itself is simple. You take a part that changes with light level and use that change to measure the light level. The device I'm promoting (this means giving away) is very small, smaller than a small LED, the more light that falls on it's face, the more it will conduct. Your DMM measures conduction, using the Ohms ranges, it will give you a digital number representing conduction of whatever you put between the leads. This means if you put the two leads of the detector between the leads (one lead to each) and have the meter on the proper range it sill show conduction and therefore the light level. A number representing the light level.

There are problems with this sort of system in measuring the exact level (say in Foot Candles). First off the numbers go 'backwards', more light is lower numbers. And twice the light isn't half the number (or any logical one, only smaller). However, it is repeatable, that is it will give you the same number each time for that level of light.

So what we need to do it figure out what that number will be and watch for it. In practice, this means putting the sensor 'looking at the light' a foot or so away, turning the light on and *inserting a filter that removes half the light*. Note the reading, remove the filter (reading number goes down due to more light) and wait. When the level returns to the 'target' level (half the initial light output) the same level of light will reach the detector as when the filter was in place with a 'full blast' light at the start (when you did the calibration and noted the target meter value), the meter will show the same number again, and the test is over. You can even watch the number slowly climb up to the target as the battery runs down.

No need to study the theory, all you need to know is how it works, and now you do. FWIW, I think you (obviously) have enough interest in this stuff, and I don't think it's at all too difficult for you.

BTW, I did some checks on the Arc AAA I carry. It looks like half the light at 1.5 Volts in, comes at a bit over .95 Volts. Sometime I'll have to look further into this, it looks like the Arc is less efficient (light out for power in) at normal levels????

Anyway, think it over. I think you can be checking against a real repeatable threshold (half light output) very easily. Puts real value in the data.

Doug Owen
 

Doug Owen

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[ QUOTE ]
Orion said:
As of the 85th hour, last night, the output was a bit less than my comparison Arc AAA. When I woke up this morning, though, the output was less than half that of the Arc AAA and the battery was at .5 volts on the multimeter. The test has ended. The "Best if installed by Jan 2001" battery has found a new home in the trash. So, I figure with a new fresh battery, I should get around 85 hours of continuous runtime, perhaps longer, of usable light. I suppose I could do the test again with a newly purchased D cell to see what it would do. Would that be worth doing?

[/ QUOTE ]

Given the surprise of apparent increased efficiency of the Arc at lower voltages (or lower ones at higher voltages....), this number makes sense. I suspect that if it does go to 1.3 Volts in 70 hours (most of the capacity), that another 20 or so hours to the .95 Volt point fits.

Remember, 'a bit dimmer' to the eye can be a lot, we don't see light in a linear fashion. They eye makes a very poor absolute detector. Mr. Al suggested some time back putting a sheet of cardboard between two wax blocks and shining the two lights on one block each from opposite sides. Then compare the blocks from the ends.

Doug Owen
 

Orion

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Okay, I believe I understand this idea, and it makes sense to me now. Do you have a working model of this?

My DMM has a dial output. I wish I'd sprung for the digital one now, but I have the dial, so I'll live with it. Perhaps one day I'll try your test out. There's plenty of Radioshacks in my town! /ubbthreads/images/graemlins/yellowlaugh.gif
 

jtice

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Doug...
Giving away?
Do you have a few of these?
I would be interested. I have no way of measuring light. /ubbthreads/images/graemlins/frown.gif
 

Doug Owen

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Analog VOMs work just fine, I kinda like 'em myself. You use the ohms function (the scale at the top that reads backwards....)using a range about mid scale if possible (probably R X 10).

And yes, if you follow the 'poor man's run time meter' thread above, you'll see I am indeed giving away both the detector cell and the necessary filter.

Doug Owen
 
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