The ArmyTek 120 day Challenge!!!

[subwoofer]

It's not out yet, but I think the Predator X may become our first to drop out, as it now looks dimmer (122.5 days).

There is no flashing, and it is still on, but to the eye the output appears to have dimmed.

If the end of runtime for these lights turns out to be a gradual fading out rather than sudden cutting out, I will judge this as the point at which I cannot see the output on a surface positioned 2cm in front of the light. I will not take it to the point of staring directly at the LED to look for a hint of glow, but instead to the point the output has dropped below being usable (in my judgement).

For the duration of the testing, these lights have been sitting in a drawer next to each other (to ensure identical environmental conditions and easy side by side comparison. The output check is based on the light shining onto the drawer front. This was done intentionally so that I did not look directly into the reflector to attempt to judge the output level.

 

[subwoofer]

The Predator X is definitely on the way out. It is now significantly dimmer.

 

[bluemax_1]

As I'd assumed, the XP-G is more efficient at low drive levels.

It's pretty amazing how accurate the 120 day rating was for the X. Now I wonder how much longer the XP-G can run? I'll guess ~10%, so another 10-12 days?


Max

P.S. actually, if the Quark runtimes are any indication (and they're generally on the conservative side), the XP-G might run as much as 25-30% longer... That's crazy. Potentially another 30 days?

 

[spankone]

Epic long haul test, good work SW. Keep going.


Sent from my iPhone using Tapatalk - now Free

 

[subwoofer]

MULTI-EVENT Update

Time interval 09/09/2013 (DD/MM/YYYY) 23:50 - 10/09/2013 07:20

Predator X has shut off completely during this time.
Predator XP-G2 has dimmed significantly (very nearly off, but not quite).


Cell condition for the Predator X - The protection circuit has kicked in, as the initial measurement was effectively 'open circuit' (the reading wanders between + and - a small voltage when this voltmeter is open circuit). However once the circuit was reset the terminal voltage returned to 2.5V.

So, for this Xtar cell it appears that the protection circuit does still operate at very low current, and the cell appears to have been taken down to approximately 2.5V. (I will run a series of capacity tests once all three lights are out).

With both Predator V2.0 models coming to the end of their run so close together I suspect this has nothing to do with emitter efficiency (as this will really affect only the brightness) and more to do with the fact the driver is running at a specific current. The slight difference in runtime will be due to slight difference in actual cell capacity.

EDIT: issues with a voltmeter mean I have updated the above.

 

[bluemax_1]

Your conclusions appear to be sound. I agree that the lights all running out this close together imply similar drive levels with individual cell capacity being the factor.

So, I guess getting 120days of runtime really is a last ditch thing as you're apparently guaranteed a dead battery at the end. Lucky for me, I have numerous off-grid recharging options. Being able to have continuous illumination for that long will be the least of my worries.


Max

 

[bluemax_1]

Dbl post

 

[subwoofer]

Your conclusions appear to be sound. I agree that the lights all running out this close together imply similar drive levels with individual cell capacity being the factor.

So, I guess getting 120days of runtime really is a last ditch thing as you're apparently guaranteed a dead battery at the end. Lucky for me, I have numerous off-grid recharging options. Being able to have continuous illumination for that long will be the least of my worries.


Max

Apologies, faulty voltmeter means I have updated my previous post. The protection did work and the cell was only taken down to 2.5V.

 

[subwoofer]

NEW MULTI-Event

The Predator v2.0 XP-G2 is now out as of 10/09/2013 09:00

Its LED was still lit, but barely. I had to hold it to my eye, cupping my hands to cut out ambient light, and use averted vision to see the LED still just on.

CELL CONDITION - the cell measured 2.53V


Predator v1.2 now appears to be dimming.

 

[Wiggle]

Having both of the 2.0s quit at roughly the same time is good to see. It gives some more faith that other users should see comparable runtimes provided similar cells are used.

 

[bluemax_1]

Apologies, faulty voltmeter means I have updated my previous post. The protection did work and the cell was only taken down to 2.5V.

That's good news, to hear that it doesn't kill the battery to do that. I still can't see myself needing to run one light off the same battery without recharging it for 3 months though, (realistically even longer than that, since the light would be shut off during the day/sleeping hours).

Could you try one more thing, and that's to see if these low voltage cells can reignite the LED after a brief rest period? I'm still curious about the issue pondered earlier in the thread about lights that could remain on with nearly dead batteries, but would not be able to turn back on if shut off.


Max

 

[subwoofer]

Could you try one more thing, and that's to see if these low voltage cells can reignite the LED after a brief rest period? I'm still curious about the issue pondered earlier in the thread about lights that could remain on with nearly dead batteries, but would not be able to turn back on if shut off.

The v1.2 is still fading but is not out yet.

Assuming the protection does not kick in, once at the end of the V1.2 run, I will see if I can use the cell to light up the LED again (and try the v2.0 Predators as well). Consider though that in this instance we are not going to gain any 'rest-recovery' as the drain has been slow and extended. The other test cells have now been recharged.

 

[subwoofer]

The V1.2 Predator is now out as well as of 11/09/2013 09:00.

The LED was still lit, but again required looking directly into the reflector blocking out all ambient light with my hands.

So in this final state of barely being lit, operating the power switch does re-light the LED (though with about a very slight delay).

Taking the depleted cell (in this case measuring 2.6V) and using this in the Predator X and Predator XP-G2, it will re-light the LED, and again with a very slight delay.


So after 124.5 days, the last Predator has come to the end of its epic runtime.

Summary of events:

122.8 days Predator X dims
123.25 days Predator X off
123.25 days Predator XP-G2 dims
123.5 days Predator XP-G2 off
123.5 days Predator V1.2 dims
124.5 days Predator V1.2 off

This is a very small variation of around only 1% in runtime which is more likely to be due to the individual cells performance rather than the lights themselves.
(Xtar 3100mAh 18650 used for all lights)

The efficiency of the XP-G2 is clear as throughout the entire test this provided more light than the other versions.

What is left to do? Well considering the cells have only been brought down to 2.5-2.6V and only one has had the protection kick in, hopefully they have not been damaged. However it is not good to leave a li-ion at less than 3V for any significant time. If you use a light and trigger the protection, you will charge it again immediately. In this test, the cells could have been at around 2.5V for weeks. I am intending to check the capacity of the cells after a full recharge to see if there is any significant change. Results to be posted when I can.

 

[Mathiashogevold]

Sooo...time to do a 2*CR123 test?

 

[subwoofer]

Sooo...time to do a 2*CR123 test?

Wow that is very kind of you to offer to do that test. Let us know how you get on

 

[Mathiashogevold]

Sure, i'll PM you my adress and you'll send me the Predators to do runtime tests

 

[subwoofer]

Sure, i'll PM you my adress and you'll send me the Predators to do runtime tests

Having been deprived of the use of these awesome lights for 120 days, I'm afraid, that is extremely unlikely.

As Gollum would say "We wants it, we needs it. Must have the precious."

"Mathiashogevold wants the precious. Always he is looking for it. But we mustn't let him have it." :devil:

 

[candle lamp]

Excellent challenge. Excellent lights. :thumbsup: The result is a surprise.

Thanks a lot for your time & effort. subwoofer! :twothumbs

 

[bluemax_1]

So in this final state of barely being lit, operating the power switch does re-light the LED (though with about a very slight delay).

Taking the depleted cell (in this case measuring 2.6V) and using this in the Predator X and Predator XP-G2, it will re-light the LED, and again with a very slight delay.

Thanks for taking the time to do that test. That's good news. It means even with depleted cells at very low battery voltages, these lights can and will light up. Theoretically, that would mean it's potentially possible to use one of these lights in Moonlight mode for practically a year for 8 hours a day. That's insane.


Max

 

[WilsonCQB1911]

Who is the anonymous challenger that went out early?