14500 vs 16340

[shark_za]

I decided to test what format holds the most capacity in these two cell sizes.

First the testbed.

2x Surefire P60L modules as they are the only module I have 2x of the same.
2x Solarforce Bezels with stainless retaining rings, the Surfire ones have a little lip that seems to aid in cooling so this way they would be as close to equal as possible,
2x Ali body torches, 1x Surefire 6P and 1x Solarforce L2r.

Cells used were freshly charged Solarforces 16340 and Trustfire protected 14500.

I fired them up and looked at the output. My eye judgement says they are close to identical, variation in P60L is the only variable.
All through the first hour they ran at about the same brightness. Obviously the same bezels and modules act the same on the thermal regulation.

After 1:11 the 6P with 16340's turned off. Protection kicked in on one cell with the other one showing 3.7v

I put in some fresh cells into the 6P and compared the intensities, the 14500 equipped torch was running very close to full power still.
At 1:50 the protection in the Trusfires triggered.


40 minutes more, that a major increase in capacity!
I'll swap the modules around and do it again to counter any variations in the modules themselves. I'll also do some test with the Cytac 16340's as they seem to run longer than the Solarforces in all my other tests too.


880mAh in the 16340, yeah right !!
900 in the 14500 , no ways but a LOT more than the 16340's that's for sure.

 

[357mag1]

I wish you had AW cells in both formats to conduct your experiment with. I have found the quality of 16340 cells other than AW to be spotty at best. I feel my AW 14500s might edge my AW 16340s but need to conduct a test to confirm.

 

[hoongern]

I've seen various claims that 14500s generally have higher capacity than 16340s, which makes sense since 14500s have more volume than 16340s (~7697mm^3 compared to ~6346mm^3).

Other tests seem to confirm this - for example, in this Quark roundup review, the 16340s only lasted 30min while the 14500 lasted 47min.

I hear that this is because many manufacturers really overstate 16340 capacities, but it looks like they tend to use more realistic values for their 14500s (750mAh for the AWs at least)

 

[jasonck08]

I just did some pretty extensive testing of the AW RCR123's.

They are definitly not "750mAH cells" but I doubt anything over 650mAH exists in the RCR123 format.

Here are the numbers for the above test:

250mA = 619mAH
500mA = 612mAH
750mA = 580mAH
1000mA = 463mAH
1300mA = 361mAH

Currents much over 750mAH make the capacity drop a LOT.

I may post a chart of 14500 capacity tests. But I can tell you so far from the tests I've done, the 14500's are MUCH better cells then the RCR123's. A lot of this is probably due to the volume of the cell being about 20% larger then the RCR123's.

At 1A the AW 14500 managed 703mAH

 

[357mag1]

I just conducted a similar test using a DereeLight Javelin R2 .9-4.2v head and C2H body. I add the AA extender to switch to the 14500 format. This is a power hungry beast as you will see from the current draw.

Both batteries are AWs and were measuring right at 4.19 volts at the start of the test. Tailcap current was measured as follows:

14500 - 1605ma
16340 (RCR) - 1530ma

This light might be in direct drive at this voltage because an IMR cell showed 2035ma at the tailcap. That means the 14500 must be holding higher voltage.

I started with the 14500 and upon completion let the light cool for 2 hours then repeated the test with the RCR. Initially I left the light tail standing and in 2 minutes it was quite warm, by 5 it was hot. I held it in my hand for the rest of the test (both times).

At 20 minutes I took 3 minutes to measure tailcap current.

14500 - 1100ma
RCR - 1040ma

14500 cut off at 37m 10sec.
RCR cut off at 28m 30sec.

The light seemed to hold equal brightness through the entire run. I'm sure there was some drop off initially but it was not very noticeable to the eye.

 

[shark_za]

Swapped the modules around and saw the same thing more or less.

16340 = 1:30
14500 = 2:00
Not so rigorously timed , might have missed by a minute or two.

I am also doubting my RCR charger a little. I never see more than 4.18v while the 14500's come off at 4.21v.

 

[jasonck08]

I'd guess the 14500's have lower Internal resistance so thats why they may be charging up to a higher voltage then your RCR123's.

 

[mdocod]

shark za,

Which charger is that you are using?

Eric

 

[shark_za]

The 16340's are charged with a charger I got from Solarforce rated at 600mA. (CRB-16i?)
The 14500's are on a no name brand with similar markings without the external 12v input.

 

[mdocod]

I have tested the one pictured on the left, but not the right, they look so similar that I would venture to guess that they could be using the same electronics inside.

The way that these chargers signal that the charge is complete is based on hitting a certain charge voltage (not cell voltage). It's basically a voltage buck circuit with an output around 4.26-4.27V. When the charging voltage reaches ~4.22-4.25V (varies from unit to unit), the light turns green, but the charger is technically still charging and will continue to trickle the cell until it finds an equilibrium of self discharge bumping up against the chargers falling output current with rising voltage. (FYI: trickle/float charging a li-ion cell is very bad for it, please make sure to always remove your cells as soon as possible after the light turns green, even a little beforehand would be great as well).

Since the termination is based on charging voltage and not on a goal termination voltage, the actual state of charge will vary from cell to cell when that light turns green. higher resistance (smaller cells usually) will have a larger differential between charging voltage and cell voltage due to higher cell resistance. This will cause the light to turn green with the cell technically at a slightly lower state of charge. Larger cells in my experience, come off that charger as high as 4.23V.

Also, keep in mind that the final state of charge will vary also depending on whether you have 1 or 2 cells loaded in the charger, because those particular chargers actually only have 1 charging circuit, the 2 bays are just wired in parallel, so putting 2 cells in at the same time is like charging 1 cell with twice the capacity and half the resistance.

Also, (yes another also) there are going to be naturally variances in termination voltage from one charger to the next as the various parts used to build the charger all come with a range of possible tolerances in actual values. This means that no 2 chargers will charge exactly alike.

FYI, there is absolutely nothing wrong with 4.18V off the charger, I would prefer that over 4.21V any day.

Eric