My 16340 lights perform better than my 14500 lights

I like to do run time charts for my lights and one thing that has struck me is that my Fenix PD25, Fenix E15, and Jet II MK all have more efficient run times on a 700mAh 16340 battery than the Fenix LD11 and LD12 do on a 800mAh 14500 battery. Now what I do is pick an output that is similar on all lights such as level 3 (not the turbo) and then I take the area under the curve (output times time). I found the LD11 and LD12 to lag the others by about 30% and then if you take into account that the 14500 battery I was using has 100mAh more, then that even makes the 30% even worse.

I believe the reason for this has to do with the fact that these 14500 capable lights are designed to utilize an AA battery too.........so the voltage range is 0.9v to 4.20v. Whereas the 16340 lights just use CR123A's or 16340 batteries and the voltage range is a lot nearer the forward voltage drop of the LED. That is just my guess at this time. Designing a driver to cover the range from 0.9v to 4.20v must be a lot less efficient than say a driver that just has to buck the voltage rather than to switch from buck or boost.

Now I realize that this is heavily weighed on the Fenix side, but I already know that the Nitecore MT10A switches to PWM for voltages above the Vf of the LED. The MT10A is very efficient on AA batteries though. In previous testing I found the 4Sevens Quarks that would run 0.9v to 4.2v to also drop in efficiency from other lights that are designed to just run an AA or to just run lithium ion battery.

So my conclusion is that I have taken a stronger liking to the single CR123A/16340 lights and realize that the strong point of the AA/14500 lights is their AA capability.

Maybe it depends on the manufacturer ... I've only just got my 1st 16340 which is a Jetbeam II Pro and whilst a brilliant light it's run times at 100 lumens don't come close to the run times of my Manker E11 and T01.

Find yourself an Astrolux SC

Witterings said:

Maybe it depends on the manufacturer ... I've only just got my 1st 16340 which is a Jetbeam II Pro and whilst a brilliant light it's run times at 100 lumens don't come close to the run times of my Manker E11 and T01.

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I really don't think its manufacturer related but more due to the technology of the wide voltage range. Jetbeam II Pro should perform as good as my Jetbeam II MK which was pretty good and beat out my LD11. I don't have the Manker E11 but from this review's runtime chart:

http://www.candlepowerforums.com/vb/showthread.php?420275-Review-Manker-E11-AA-14500-XP-L post #20......I can see what run time he got.

The Fenix LD11 with just XP-G2 LED and run with Keeppower 800mAh battery held about 187 constant lumens constantly for 92 minutes beating out the Manker E11...........and again I'm just saying the 16340 driven lights beat out the LD11.

I personally use the 16340 over the 14500.
The E15 is one of my favs, love the runtimes but always thought the 14500 sized Fenix would give better runtimes.
This could be due to the driver voltage range like you mentioned.
When measuring one should also take into account the driver efficiencies from different manufacturers.
So better to compare runtimes from a 16340 light against the same manufacturer's 14500 light.

The stated runtimes from some can also be exaggerated a bit.

Thanks for the info, hiuintahs.

I'm into efficiency and test my lights for output, runtime, and current draw, and I have a good lightbox. However, I really only focus on the lower output range (~0.3/3/30 lms) as I probably use that 45/40/10% of the time, respectively. High/Max outputs with these small cells just ain't worth sustained usage - get an 18650 light for that.

My collection is heavily skewed toward AA/14500 lights, since I'm an ultra-light camper/traveler type, and the ability run 1-4.2V means I can rig my light to run on any battery (paperclip/tinfoil in wallet), although AAs are the easiest cell to find anywhere in the world, and I usually carry another AA gadget anyways. For me, the wide voltage option = infinite runtime, which I could have used a couple times in some real pinches.

I only own 2 dedicated CR123/16340 lights (HDS 325, 47 Mini Mk2) and I find among the lower output modes, efficiency is all over the map - certainly between different manufacturers, sometimes between different modes on the same light, and sometimes even between different samples of the same light. At sub-lumen outputs the HDS is rather inefficient, the Mini is average-ish, and my 1-4.2v Quarks are excellent. The Mini's low mode (17 lms) is the highest lm-hours I've runtime tested (289 lm-hrs / 2.2 w-h) but I've also gotten ~280 lm-hrs / 2.4 w-h (boosted Eneloop) from a Quark, SC52, and D25A at similar outputs. I'm quite certain the Mini Mk2 is technically more efficient than the HDS, but ultimately the HDS's ideal mode spacing (user programmable) will yield most folks a longer runtime between battery charges.

I do find the broad voltage Quarks less efficient on high/max, particularly on a single NiMh, but it's low-end efficiency and ideal-for-me mode spacing, make it *MY* most efficient light, and by a good margin (not to mention all the Lego-able battery tube options and emergency ability to run any cell).

I don't disagree with anything you said - rather I just come to the opposite conclusion due a different spin on the issue.

reppans, nice assessment. Most of my run time tests have been in the high or medium modes because I don't have the patience to do the long run times. I just figured that if they are efficient at the medium mode that it would also do a good job at the low mode. Ya, most of my usage is in the lower lumens too. I see people asking for the brightest 14500 light and I kind of think its a waste and agree that a 18650 light is better suited for those turbo outputs.

It's just that when I found that medium and high run times were not as efficient with the samples of AA/14500 lights (with a 14500 battery) as they were with the CR123A/16340 lights...........I was a little taken back due to the fact that the 14500 cells I was using were 100mAh more than the 16340 cells. I plan to keep the AA/14500 lights that I have regardless because I agree with you about the convenience of AA capability. Also I have found that the newer lights such as Fenix LD11, LD12, NC MT10A, ET D25A, etc are very good (efficient) with AA cells.

So my emergency car light is a Fenix LD11 that has a 14500 battery in it. But I also have in the glove box a 4xAA storage case with 1 alkaline, 1 Eneloop and 2 L91 Energizers as spare batteries. If I get into a long term emergency situation without charger available, I prefer to use the less expensive and rechargeable batteries first before having to resort to the expensive L91 primary.

Yeah, runtime testing low lows can be painful, but current measurements are a good proxy, and no reviewers even do this simple test. I am appalled by how badly even CPF-respected manufacturers exaggerate low lumen efficiency (output and runtime) - lumen-hours overstated by factors of 4x are not uncommon.

I actually started using AAAAs from a 9v and batch testing to minimize the runtime test PITA. But after upgrading my DMM, I mostly rely on current measurements now - they triangulate well to my actual tests.

My personal favorite camping/travel/emergency rig is a low voltage Quark running a 16650 cell: 0.6" longer than a 14500, but 3x the capacity, and it will fit 1x CR123 or AA/AAA (of any chemistry) with tinfoil spacer. Speaking of chemistries... the AA size has them all.

reppans, what DMM are you using? Asking because I'm thinking "upgrade" myself.

I'm using an Innova 3320 auto-ranging from Amazon (even cheaper now!). It's not in Fluke's quality range, but I've had no problems with it and it ties up well with my runtime tests.

It will only meter current down to 0.01 mA (10 uA) so perfectly fine for moonlight testing, but not really granular enough for parasitic drain comparisons between efficient electronic clicky lights (usually <10 uA). It will flag a reasonably inefficient parasitic light - ie, my '14 Neutron on 1AA is drawing 0.11 mA (110 uA) or 2yrs, which ties up with Selfbuilt's 56uA reading on 2AA or 4yrs.

This is relevant but I don't remember where I got it from, I just have it saved in my notepad:

An RCR123 (16340) rated at 750 mAh at 3.7 volts = 2.775 Watt Hours

Dimensions are as follows: [pi*(8mm^2 )] 34mm = 6836.1 mm^3


So we come up with **.000405 Watt Hours per mm^3**.


A 14500, also rated at 750 mAh at 3.7 volts also = 2.775 Watt Hours


Dimensions: [pi*(7mm^2 )] 50mm = 7696.9 mm^3


So we get **.000361 Watt Hours per mm^3**.


Turns out the RCR123 format is actually *more* energy dense than the 14500.


Unless you're talking about *primary* CR123 cells in which case we have:


1500 mAh at 3 volts = 4.5 Watt Hours


With the same dimensions as an RCR123: [pi*(8mm^2)]34mm = 6836.1 mm^3


So we're looking at **.000658 Watt Hours per mm^3** which is more energy density than either secondary cell.


I'd also like to highlight that the CR123 format is more than 21% smaller by volume.


Cheers!


-G

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I find this to be true with Zebralights. My SC32w can run a good deal longer on H2 than my SC52w can run on H1. This is despite the fact that the difference in brightness is VERY small, yet the difference in capacity is quite large (800mAH vs 550mAH). I'm guessing that this is due to inefficiencies resulting from driver compromises made in the name of accommodating a wider voltage range.

An RCR123 (16340) rated at 750 mAh at 3.7 volts = 2.775 Watt Hours

The problem here is that a TRUE 750mAH 16340 doesn't exist.