Craig @ Ledmuseum - questions galore

[Klaus]

Craig,

sorry to bug you but some question still are on my mind regarding some of your latest test reports - and some older ones too

In the other thread you created on your test of the lambda illuminator there was some discussion regarding runtime - where my points on 6 hours @ 700ma were answered by Daniel that the current is going down over time quite a bit (like 450, 350, 250) - with such claims I would be highly interested in some runtime / brightness test with your test-setup - possibly comparing the iluminator to an ARC LS and if you have / can get an ZLT+ too.

Also of interest might be a clarification of your ProMetric test data on lambdas LS light compared to an SF E2 - your data would show that both throw pretty much equivalent beams / brightness - which would be quite revolutionary I would say - an overdriven 18lu part beating / matching the most highly praised 60lu light available hands down ??

If possible and as time permits I would also highly appreciate the following additions to your older ARC LS runtime / brightness charts

- ARC LS on NiMhs
- Lambda Illuminator

TIA

Klaus

 

[lambda]

Klaus,

Let me see if if I can explain this a little.

If you just load in fresh alkiline batteries, hit the switch and let it run, you're going to get about 2 hours of fairly consistent bright output, with some noticeable dimming toward the end of the last half hour. If you used those batteries the next day, you would get another 45 min or so of run time. This is beacause AA cells don't like supplying large amounts of current like the Illuminator needs.

If you use the light for a few minutes each day, you will get much longer run times, as the batteries get a rest between each use. However, each time you turn it on, the batteries will normilize at a slightly lower voltage because of their previous use. So, although you get longer run times over an extended period of time, it is at slightly less brightness each use, as the batteries run down.

Now the 6 hours may very well not be acheiveable, it's just a guess on my part what the theoretical possible battery life could be if used intermittently.

If the Illuminator was not so bright, much better use of the batteries would result, as they would not be drained so fast. Yes, efficiency went out the door on this one, as it was designed for it's brightness, not run time. If this were a D cell flashlight, then it would be pretty efficient, as the larger batteries won't degrade so fast from the high current.

Also, the circuit was designed to cut off when the battery voltage gets under 1.4V (0.70V / cell) so as not to damage my NiMh rechargeables. NiMh maintain a very flat voltage over discharge, and therefor also provide a very constant brightness also. If it didn't cut off the voltage at this point, better use of non-rechargeable batteries would result.

Like I said before, many trade offs were made in the design between efficiency, brightness, cut off point, etc.

This light was made to be a kick-*** bright little flashlight that was small enough to carry every where and use cheap AA batteries.

In the end, it's the batteries that will determine it's performance; what ever juice is left in them, it will suck out as fast as it can and be as bright as it can.

Probably should have been built in a D cell light, but I wanted D cell brightness in a small AA cell light. That's what drove me to make the Illuminator.

As for the brightness, I have to admit that the color temperature of it at times makes it seem not so bright during the day, but each night reconfirms it really is that bright.

Here's a real world use, actually kind of funny. A couple nights ago some young teenage girls were out walking the neighborhood; most likely all sleeping over at one of their houses, as the neighborhood is out in the country side. Anyway, they came down the street and played Ding-Dong Ditch on my front door. (anoying American childhood custom of ringing someone's door bell, and then running away). What they didn't know is that I was sitting outside in my screened-in porch upstairs on the second level, and had actually watched them come down the road with my night vision camera. I also had my trusty Illuminator at my side.

After they rang my door bell, they all kind of stopped in the road about a hundred meters away. I stepped out on the walk way upstairs and flashed them with the illuminator while looking through the night vision. To my suprise, they were scared by the light! I heard something to the effect "what the sh_t is that!" as they all scattered from view. It was a very dark overcast night, and apparently they could tell they were being illuminated, and didn't like it much.

I hope I made some sense here about the battery run times. It has more to do with the behavior of AA cells under heavy load than any other single factor. And brightness, yes, it's very bright for it's size, and I think 2 hours+ on a set of AA cells is a reasonable run time for that level of output.

Well, I better get back to work on these flashlights before they send the black helicopters to my house...........

And I too would be interested in run time charts....

 

[Daniel Ramsey]

Perhaps we should adopt a "1-2-3" test, it would be like this:
One hour continuous run time,with a light measurement and current draw on a gradient graph scale.
One hour rest.
Repeat another one hour test of brightness and current consumption.
Another one hour rest.
Repeat for a third time to finalize results.

It would be best to show this as a gradient scale of various types of batteries from alkalines to lithiums or nickel metal hydrides.

This 1-2-3 test is best for hi performance compact LED lights.

For larger units using larger batteries it can also be done I think.

 

[Alan]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by lambda:
What they didn't know is that I was sitting outside in my screened-in porch upstairs on the second level, and had actually watched them come down the road with my night vision camera.<HR></BLOCKQUOTE>

I understand now why you don't have time to respond my email

Alan

 

[Klaus]

Thank you guys,

Craig - would love to see those tests added as soon as you have time & parts at hand - TIA

What confused me on the E2 / Illuminator comparison was that the beam profile looked so similar to me between the two.

Lambda - you got me confused - you write that using AA´s constant on would result in "fairly consistent bright output" which I would say describes pretty much a regulated circuit - the AAs voltage gets lower and to keep the output stable the circuit draws more current - but when doing an off/recover/on the cells would "settle" at lower voltage and the flashlight would be dimmer - correct ?

Now here my confusion starts - where is the difference between a lower voltage during operation or a lower voltage after some rest ? After some rest the voltage of the cells will be even higher than befor when being shut off ? This would only make sense when your circuit adjusts the output current mostly at one point on startup after seeing the input voltage based on whatever formula and tries to keep this current from then on - this would be quite innovative then but could also cause some unwanted effects.

Could you be so kind to clarify if this is how the circuit works - or if I got this wrong then could you explain what you think would make the current lower on startup with used but somewhat recovered cells compared to the current on cells being rundown continously where obviously also the cells voltage is on a pretty steady slope when talking about Alkaline AAs which I suppose we talk about as Lithium AAs and Nixx cells wouldn´t have that high-current draw issue as much as Alkalines anyway. Talking about other cells I also would like to ask you about your runtime on your NiMh cells.

TIA

Klaus

 

[lambda]

Klaus,

My observations are that AA cells have a problem delivering the required current. A half used battery that has sit for say a week, won't deliver the same voltage/current (under load) as a half used one that rested only over night. Seems the batteries 'settle' out to a lower voltage over time.

I've taken some old used batteries and put them in the Illuminator and gotten say 1/2 hour of not so bright light. Where if it had been used the next day, it works much better. I think it's a result of draining the batteries at high currents, they just don't behave the same as they do at lower discharge rates.

These observation are based on Energizer AA cells; other batteries may behave differentlty.

I hope I haven't confused you more with my 'explanation'.

 

[The_LED_Museum]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Klaus:

In the other thread you created on your test of the lambda illuminator there was some discussion regarding runtime - I would be highly interested in some runtime / brightness test with your test-setup - possibly comparing the iluminator to an ARC LS and if you have / can get an ZLT+ too.<HR></BLOCKQUOTE>

This one will have to wait just a bit - a couple of days ago I loaned my Illuminator to another CPF member for a camping trip and said he could use it until he got his in 2-3 weeks. (The things I do for CPF alumni...)

As soon as I get it back, I'll set up a runtime/output curve for you.

As for comparisons, I've already run multiple battery types through an Arc-LS, but I do not have any flashlight with a ZLT in it, so a comparison with one of those cannot be done.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Klaus:
Also of interest might be a clarification of your ProMetric test data on lambdas LS light compared to an SF E2 - your data would show that both throw pretty much equivalent beams / brightness - which would be quite revolutionary I would say - an overdriven 18lu part beating / matching the most highly praised 60lu light available hands down ??<HR></BLOCKQUOTE>

It comes down to beam width and beam configuration. The Illuminator has a *very* hot and narrow center compared to other LED lights and to the incandescent E2. The only way these two lights could be properly compared for brightness is by doing a total luminous flux measurement, and I do not have an integrating sphere or the correct instruments for this measurement, nor anywhere near enough room here to set one up even if somebody gave me one.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Klaus:
If possible and as time permits I would also highly appreciate the following additions to your older ARC LS runtime / brightness charts

- ARC LS on NiMhs
- Lambda Illuminator<HR></BLOCKQUOTE>

I can do both of these, but only as time and computer availability permits, and only after the return of my Illuminator of course.

You must have been reading my mind. :O

 

[Klaus]

Thx Lambda,

what you say makes sense somehow - while I have to admit that my experience with Alkalines at that load level is limited as I very much more like to use NiMhs anyway ...

Klaus

 

[Klaus]

Thx Lambda,

what you say makes sense somehow - while I have to admit that my experience with Alkalines at that load level is limited as I very much more like to use NiMhs anyway ...

But following your points on Alkalines - still not shure why you (or Daniel) say that using the cells with some time to rest in between your circuits setup / behaviour would result in lower current for the LS resulting in that long runtime though ?

In my understanding a regulating circuit setup for a specific current will try to get that current out no matter if the cells it gets its juice from had been running continously or with some rest - but anyway - guess some nice testing by Craig, Chris or Doug might shed more "light" on this.

Thanks

Klaus

 

[Daniel Ramsey]

Don't take my word on anything!

Looks like a second, third and fourth party needs to evaluate lambdas circuit.

See everybody in a couple of months or possibly on a sunday, if I am in town or in state. So far this year its going to be a very busy one for me, in a day or two I take delivery of a brand new concrete mixer to add to our fleet, I should have our new plant online in about two months or less and in the meantime because our snow IS STILL ON THE GROUND

because of an unusually long winter all our major state concrete jobs are being delayed until they are almost back to back, that means I will practically live at work this season.

$$$$$$$

 

[TripleDouble]

Klaus, those current regulating circuits do not provide perfect current regulation, and are probably voltage dependent. Higher voltages mean a "closer to complete boost", while lower voltages provide a "less complete boost", i.e. lower currents. For example, with one particular ZLT circuit, fresh AA nimh's gave me ~350 mA, while fresh Alkalines gave me ~370 mA. I did not perform any runtime comparison tests.

 

[Klaus]

TripleDouble,

thx - and yes I know - my points where that I still don´t get the difference between the claim of continous brightness when run continously and lower brightness due to lower current when the cells got some rest.

Klaus

 

[Lonewolf]

lamnda:
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR> Also, the circuit was designed to cut off when the battery voltage gets under 1.4V (0.70V / cell) so as not to damage my NiMh rechargeables.<HR></BLOCKQUOTE>

Am I to understand that you designed this light with rechargeables in mind? Now I need to go out and buy some rechargeables to use in my Illuminator because I don't have to worry about draining them to much.

 

[moraino]

Lambda,

Is the heatsink of the light has good contact like your MAG 3D direct drive?

At that current it should be very hot though.

 

[Bushman]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by moraino:
Lambda,

Is the heatsink of the light has good contact like your MAG 3D direct drive?

At that current it should be very hot though.<HR></BLOCKQUOTE>

It is as good or better than the direct drive but because there is less surface area to sink the heat into the illuminator does get a little warm after 10 min or so of use but still well within the operating specs. of the led... mike