NiteCore D20 Review - 2xAA - RUNTIMES, BEAMSHOTS, DETAILED PICS and more!

[jdong]

Call me crazy but I think the tint on the D20 looks better, though the L2D seems brighter at that distance.

 

[selfbuilt]

1. Fenix TK20
2. Olight T25
3. Eagle-Tac P10A2

I don't have the P10A2, but can confirm the TK20 has the best throw of the class. Still need to do runtimes on the TK20 as well ... it will also be included in my eventual 2AA round-up.

 

[PlayboyJoeShmoe]

THANK YOU for doing the review!

I KNOW it's a TON of work!

I know there is no WAY I could do it!

So THANKS!

 

[hwoont64]

wonder if the head is compatible with the ex10 or the d10

 

[selfbuilt]

I KNOW it's a TON of work!

Thanks PJS. FYI, I am planning to shorten the length of my reviews going forward, given the workload involved with them (just too busy at work these days). I'll also be doing less low mode runtimes on primary lithium cells (CR123A/L91), as I am burning through them at an alarming (and expensive) rate! :candle:

wonder if the head is compatible with the ex10 or the d10

No, they are different diameters and will not thread on to each other

 

[StarHalo]

Haven't had a chance to do runtimes yet, it's in the queue.

I know you don't normally do minimum output runtimes, but if ever there should be an exception, this would be it; The main selling point for a 2xAA light, for me anyway, is maximum runtime. I'd really like to see which of these lights could win a moon mode marathon - I know the L2D is the current reigning champ at ~77 hours, and though the JetBeam can go far lower, it probably doesn't have the efficiency to go the distance. I'd wager the D20 is the one newcomer that stands the best chance of beating the Fenix..

Even if you just do a basic "To 50%" time list without a chart, this would be some very helpful info.

 

[selfbuilt]

I know you don't normally do minimum output runtimes, but if ever there should be an exception, this would be it; The main selling point for a 2xAA light, for me anyway, is maximum runtime.

You make a good argument StarHalo ...

...but I'm starting to think that minimum mode runtimes are just too problematic. Now that we are starting to see lights with really low output modes, the problem of Vf variability seems to be becoming huge at these outputs. I'm seeing variability in runtime reports on the order of > 3-fold for some lights on low settings than aren't even as low as the ones we are discussing here. And my discussions with various light makers confirms that this is not an isolated problem.

Simply put, it's looking like low Vf lights are running at considerably higher drive currents than high Vf ones for many circuits on low. Although this effect is often negligible at higher outputs, at really, really low ones it wrecks havoc on runtimes. Without a wide range of samples to test, it's impossible to know how representative my one specimen would be.

Honestly, I could easily imagine the range of runtimes being anywhere from 3 days to 3 weeks. One sample point in there is likely to be highly misleading. I think what we really need now is for makers to test high and low Vf extremes, and report the range of results obtained. I expect you'll see days to weeks variation! :sigh:

EDIT: I see Chevro has recently posted D10 and EX10 Min runtimes, where he got ~4.5 days for the D10 on one Duracell Ultra. My D20 has about the same min output level as my D10 cree, so I would expect pretty decent runtime. It won't be the most accurate, but I've just started a Min run of my D20 on 2 regular Duracells in a corner of my closet. At least this way I should be able to tell you when the run stops, +/- half a day or so, since I go into the closet each morning and evening. But please keep in mind that this is just for personal "entertainment" purposes - Vf variability could hugely affect ultimate results.

 

[cerbie]

I was under the assumption that the D20 was a fairly high drive current light (relative to single-digit milliamperes), regardless of output. Is that not the case?

 

[selfbuilt]

I was under the assumption that the D20 was a fairly high drive current light (relative to single-digit milliamperes), regardless of output. Is that not the case?

Relatively speaking, I think that's true of many of the current continuously-variable lights - since they tend to be optimized for max outputs and not low. Unfortunately, I'm not able to confirm current draws (even battery draw estimates are problematic with my DMM, since I know it introduces too much resistance).

 

[ergotelis]

I saw that you updated some graphs, but isn't it strange about the runtime of the LD20? It should be about the same with L2d, did they change anything?thanks!
Would it be possible for you to repeat that test?Or you have done it already?Thanks!

 

[selfbuilt]

I saw that you updated some graphs, but isn't it strange about the runtime of the LD20? It should be about the same with L2d, did they change anything?thanks!
Would it be possible for you to repeat that test?Or you have done it already?Thanks!

I haven't re-tested the the LD20 on turbo yet, but I did try the same batteries from the LD20 run in the L2D, and got 1:28 runtime, so it looks like that's not the explanation. Just did the Hi mode test on the LD20 and got similar output and runtime to the L2D (but haven't graphed it yet). The Turbo mode could be an anomaly - I'll keep testing and we'll see.

As for the D20, Nitecore has pointed out to me that dimensional stability and overall strength requires a slightly larger build in 2AA format over 1AA. Also, since they designed the light for rugged use, they weren't as concerned about keeping the weight or size down. But they did indicate that they are considering other light designs, so user feedback is welcome.

 

[phantom23]

Graph curve for LD20 is also slightly different. Maybe they've changed something else than reflector...

 

[selfbuilt]

Just updated the Med-Hi graph with the LD20 Hi (not Turbo) and Olight T25 Level 4 results.

Hit your browser reload if you don't see the traces.

It looks like performance of the LD20 on Hi is not so different from the L2D on Hi. I'll do the Med runtimes later - in middle of a few other lights right now.

 

[Kamakazikev24]

Hi there, In the real world is there much difference between the output of the D10 and the D20? I would like to know if you feel that the extra size of the D20 is worth it.
Thanks Kam.

 

[selfbuilt]

Hi there, In the real world is there much difference between the output of the D10 and the D20? I would like to know if you feel that the extra size of the D20 is worth it.

Personally, on standard batteries, I don't think the extra ~20-25% or so output of the D20 makes a big difference in every day use (recall that the D10 is one of the brightest 1AA lights).

The advantage for me is really the longer runtime of 2AA. This is why I typically recommend 2AA lights for general use by non-flashaholics.

As for EDC, the extra heft of the D20 probably makes this light most suitable for those who have jobs requiring a heavy-duty light source. Most of us will get by just fine on an 1AA light.

 

[Kamakazikev24]

Thanks for the advice, I got a D20 today and I will post up my views soon but I have a question. It's been on high for 45 mind on Ni mh 2500 batts and the temp is 48.3 c at the heat sink and 56.1 on the lens. Is that ok? Or will the light be suffering!
Thanks, Kam.

 

[Hitthespot]

Great Review as usual Selfbuilt. Gave me the exact information I needed to make a purchasing decision on a two AA light.

Thanks for your efforts, I know what it takes to complete an in depth review like this.

Bill

 

[Kamakazikev24]

Hi there! I'am a new member from the UK. First up I would like to thank everyone for all the great information on this site, Its been a big help while trying to find a replacement for my Maglights....

I read some good and not so good reviews and comments on the Nitecore D20, but took the plunge anyway as I liked the look of it, AA batterys are 'free' from work LOL (I'am a signal engineer on the railways) and of all the lights I have seen the clip is actually in the 'right' place!. By that I mean at the END so when I have it in my pocket I dont have a couple of inches sticking out (just not the done thing!)
Why most lights come with the clip halfway up the light I dont know, but it feels really secure when in my pocket as only the clip and the end is showing, with nothing to catch anywhere.

This light is perfectly made, finish is 110% and thankfully the piston switch thingy (technical term) is spot on! Even with rechargable batterys inside there seems to be plenty of feedback and the movement was great straight out of the box.

As for brightness, well I dont have meters so I cant comment and do graphs, but the way it blows my 4 D cell Mag away is Sooo CooL!

Its a perfectly white light, with no rings at all, it throws further than I need it to and when you want to calm it down it goes to a great low level which can be used without starting the dawn chorus!

On two (OLD) AA Ni Mh 2500 Batterys I got Approx 70 mins before she dimmed down, which for the amount of light coming out the business end was impressive.

As I posted before I am still waiting to hear if the temp was OK....

Thanks for the advice, I got a D20 today and I will post up my views soon but I have a question. It's been on high for 45 mind on Ni mh 2500 batts and the temp is 48.3 c at the heat sink and 56.1 on the lens. Is that ok? Or will the light be suffering!

......I looked at it afterwards and saw what I thought was a very straight crack across the emitter base but after looking on here it seems it is made that way and I had not noticed it before.

So Yes, Very happy with my new buy.

Thanks again for this informative site. Kam.

 

[StarHalo]

Thanks for the advice, I got a D20 today and I will post up my views soon but I have a question. It's been on high for 45 mind on Ni mh 2500 batts and the temp is 48.3 c at the heat sink and 56.1 on the lens. Is that ok? Or will the light be suffering!

The general rule is the hand test - if you can hold it and it's not uncomfortably warm, then you're fine. Note also that your hand acts as a heat sink, so just the act of holding it helps cool the light.

 

[Kamakazikev24]

Yeah OK, so after my last post it all starts going downhill! Erratic switching, switching itself off and from high to low in no order It's been sent back to swap it for a Nitecore Extreme....Hopefully that will be better.
Kam.