18650 & 21700 battery internal resistance cold testing

16 posts / 0 new
Last post
maukka
maukka's picture
Offline
Last seen: 8 months 1 week ago
Joined: 12/31/2015 - 04:15
Posts: 2175
Location: Finland
18650 & 21700 battery internal resistance cold testing

edit 23.1.2019: added 18650 results at the end of the post

Many people report that lights can’t sustain their turbo modes in freezing temperatures. I tested four 21700 batteries and one 18650 after they had been outside in (-12°C) for an hour. Their surface temperature was at -1 to -3 degrees Celsius when I started the internal resistance (Ri) measurement. The test was done inside. I did a similar test previously on some 16340s.

For example, estimating that a high power light draws about 10 amps, the voltage would drop from 4.2 volts to about 3.3 volts on a battery with an Ri of 0.09 ohms. This is such a low voltage that the light would most probably assume that the battery doesn’t have enough charge to sustain the turbo output.

A Samsung 30T with an Ri of 0.05 ohms would probably perform better in cold temperatures on high modes. Samsung 30Q acted as an 18650 reference, and it was significantly worse than any of the 21700s. None of the cells were brand new and have several discharge cycled under their belt.

Using a lower high mode a while would warm up the battery, after which the turbo max mode might work.

Testing was done at 5 amps DC at room temperature (22°C) and at about -1°C.

Acebeam 21700 5100mAh IMR21700NP-510A
Warm 0.039 ohm
Cold 0.088 ohm

Liitokala 21700 4000mAh Lii-40A (Manufactured by Lishen)
Warm 0.025 ohm
Cold 0.089 ohm

Wuben 21700 4800mAh ABD4800
Warm 0.043 ohm
Cold 0.097 ohm

Samsung 30T 21700 3000mAh (Vapcell branded)
Warm 0.011 ohm
Cold 0.053 ohm

Samsung 30Q 18650 3000mAh
Warm 0.051 ohm
Cold 0.159 ohm

edit:

Data for a couple of 18650 cells. They were outside in -4°C for 3 hours. Surface temperature was 0°C before the discharge test started so not quite as cold as in the 21700 test. The same 30Q performed better this time around.

Very similar results to the previous tests. The lower the internal resistance warm, the lower it is when cold. When at 0 degrees, there’s consistently about 60 milliohms more resistance compared to room temp of 23°C. Sanyo GA increased 80 milliohms.

Samsung 30Q
Warm 0.052 ohm
Cold 0.112 ohm

Samsung 25R
Warm 0.033 ohm
Cold 0.090 ohm

Sanyo GA
Warm 0.069 ohm
Cold 0.149 ohm

Sony VTC5A
Warm 0.027 ohm
Cold 0.083 ohm

Sony VTC6
Warm 0.037 ohm
Cold 0.102 ohm

Edited by: maukka on 01/23/2019 - 13:35
RobertB
RobertB's picture
Offline
Last seen: 14 hours 21 min ago
Joined: 12/18/2015 - 17:49
Posts: 3742
Location: USA, Michigan

It was -14ºF (-26C) here yesterday. I wonder if a 30Q would work at all at that temp.

maukka
maukka's picture
Offline
Last seen: 8 months 1 week ago
Joined: 12/31/2015 - 04:15
Posts: 2175
Location: Finland

I used a 30Q in a Skilhunt H03 yesterday at -25°C for half an hour and it worked fine. Didn’t use maximum output though (did once cycle through the modes and passing by turbo, nothing of note happened).

teacher
teacher's picture
Offline
Last seen: 2 years 3 months ago
Joined: 02/23/2016 - 19:04
Posts: 9596
Location: NE & SW Alabama

Interesting information maukka, thank you for sharing it. . Thumbs Up

You never know how a horse will pull until you hook him up to a heavy load./"Bear" Bryant 

 .................................. "Slow is Smooth, Smooth is Fast" ...................................

       Texas Lumens Flashlights / M4D M4X Deals : sign up - save $$$$  

         Rudeness Level _ mΩ _ {width:70%} _ LightWiki _ LED Tint Chart  

      Xlamp size chart _ BatteryU _ Flashaholic? Need Professional Help???            TheOriginal _ TAB _ LightSearch _ BatterySearch _ 14500's _ DiCal 

 

                                             

BlueSwordM
BlueSwordM's picture
Offline
Last seen: 2 weeks 3 days ago
Joined: 11/29/2017 - 12:34
Posts: 5608
Location: Canada

Are you using a 4 wire measurement?

My NCR20700A 20700 has a DC internal resistance of 15mOhms at 20°C.

A Samsung 30T should be even lower than that.

Are you counting lead/contact resistance too?

My very own high current Beryllium Copper springs Gen 3:
http://budgetlightforum.com/node/67401
Liitokala Aliexpress Stores Battery Fraud: http://budgetlightforum.com/node/60547

maukka
maukka's picture
Offline
Last seen: 8 months 1 week ago
Joined: 12/31/2015 - 04:15
Posts: 2175
Location: Finland

Yes, I use a 4-wire setup. 15mOhms sounds low for NCR20700A, HKJ measured 0.03 ohms.

On the other hand, I just checked one of my old measurements which show an Ri of 0.012 ohms for the 30T. Other warm measurements do match up though.

edit: thanks for the tip, checked the data again and seems I did the calculation wrong originally, actual Ri is 0.011 ohms.

Cereal_killer
Cereal_killer's picture
Offline
Last seen: 1 year 11 months ago
Joined: 07/22/2013 - 13:10
Posts: 4005
Location: Ohio

Wow I’m surprised the 30Q did so bad (relatively)! Was it in the same condition, age & cycle count wise as the 21700’s?

 RIP  SPC Joey Riley, KIA 11/24/14. Now I am become death, the destroyer of worlds.

moderator007
moderator007's picture
Offline
Last seen: 1 month 2 weeks ago
Joined: 12/23/2012 - 04:47
Posts: 3740
Location: North Carolina

Even measuring the Ir right off the charger lowers the reading. Charging or using the cell heats up the internal cell temp.
I have noticed when running a discharge test with a cooler than room temp cell say 60 degrees F, the voltage sags and lowers until it plato’s then after a minute or so after heating up from the load, the voltage climbs up a little then plato’s again where it starts to decrease again until depleted. A warm cell can give you higher lumens than a cool one.
.
Last night I installed a blue spring in the tail cap of a UltraTac A1 modded with a mtn boost driver and a xhp50.2. In my basement where most all my hobby junk is kept, the temp probably stays around 60 F. The first try with a 14500 Efest I got about 1600 lumens. Battery should have been around 60 F. I charged the cell back to 4.2v and stuck it in front of a portable electric heater for a minute. Picked up the cell and held it in my hand tight for about another minute, letting the heat absorb in the cell. Ran the test again for 1850 lumens OTF of a A1. With a few more mods maybe I can reach 2000 OTF.
I would guess to say that the cell temp on the second test was around 80 to 90 F, just a guess.
.
Thanks Maukka for this valuable test data that shows cell temp affects IR readings.

Freedom
Freedom's picture
Offline
Last seen: 2 years 7 months ago
Joined: 01/11/2016 - 04:18
Posts: 271

I just thawed out an 18,000 mah jump starter (300A/600A peak) from -16F. Fully charged/like new condition previously…dead…no lights…nothing. After it was thawed out it started charging somewhere between the 4th and 5th indicator lights out of 5 like normal. I’m guessing that it tripped a LVP circuit.
I wouldn’t have kept it out there if I hadn’t misplaced it yet deep freezing these cells at all is just a hassle in my opinion.

Domari Nolo “I Refuse to be Subjugated” (1st Pennsylvania Regiment Flag) https://www.1stcontinentalregiment.org/blank
(Flagguys.com):..and man o man did they ever refuse to be subjugated. These guys were everywhere. They were important in Washington’s siege of Boston. They stayed behind and were the last to leave after covering the main army’s dangerous nick of time retreat from Long Island. They crossed the Delaware with Washington. They were “..at Brandywine, Germantown, Monmouth, and every major skirmish, and battle all the way to Yorktown..” where they fought “the most important part of the siege” according to General Steuben. These guys saw action in every one of the original 13 colonies.

Agro
Agro's picture
Offline
Last seen: 15 min 42 sec ago
Joined: 05/14/2017 - 11:16
Posts: 6861
Location: Ślōnsk

One of things that may affect 30Q performance:
it was most likely colder than the other cells, simply because it’s smaller.

Other than this….it’s surprising because I’ve seen multiple reports of 30Q doing very well in the cold.

Satan@103TFS
Offline
Last seen: 1 week 7 hours ago
Joined: 09/04/2017 - 12:51
Posts: 571

Look at that Lii 40A IR ,it’s the best for me cheap price (12 usd for 4 shiped) decent capacity and easy to buy(to where I live) at AE that make me pefer my new flashlight to be 21700 than 18650.

maukka
maukka's picture
Offline
Last seen: 8 months 1 week ago
Joined: 12/31/2015 - 04:15
Posts: 2175
Location: Finland

That sample of 30Q was picked randomly. It has tens, probably a hundred cycles and definitely isn’t the best with regard to Ri even when warm. I would probably find a better one. I’ve measured some 30Qs as low as 0.023 ohm.

maukka
maukka's picture
Offline
Last seen: 8 months 1 week ago
Joined: 12/31/2015 - 04:15
Posts: 2175
Location: Finland

I tested three 30Qs from different batches. All of them have been used and none are newer than about a year. Incidentally, the newest one also has the lowest internal resistance (the same one in the original post). They measured 0.079, 0.066 and 0.052 ohms tested at 5A fully charged straight from the charger. Relatively new they were in the 0.023-0.040 ohm range. Seems they age quite badly.

I’ll do another post with a similar test on worn 18650s such as the Samsung 25R, Sanyo GA, Sony VTC5A and VTC6. I don’t have any brand new cells to compare them to so YMMV.

maukka
maukka's picture
Offline
Last seen: 8 months 1 week ago
Joined: 12/31/2015 - 04:15
Posts: 2175
Location: Finland

Data for a couple of 18650 cells. They were outside in -4°C for 3 hours. Surface temperature was 0°C before the discharge test started so not quite as cold as in the 21700 test. The same 30Q performed better this time around.

Very similar results to the previous tests. The lower the internal resistance warm, the lower it is when cold. When at 0 degrees, there’s consistently about 60 milliohms more resistance compared to room temp of 23°C. Sanyo GA increased 80 milliohms.

Samsung 30Q
Warm 0.052 ohm
Cold 0.112 ohm

Samsung 25R
Warm 0.033 ohm
Cold 0.090 ohm

Sanyo GA
Warm 0.069 ohm
Cold 0.149 ohm

Sony VTC5A
Warm 0.027 ohm
Cold 0.083 ohm

Sony VTC6
Warm 0.037 ohm
Cold 0.102 ohm

Phlogiston
Phlogiston's picture
Offline
Last seen: 1 month 3 weeks ago
Joined: 10/27/2016 - 16:57
Posts: 988
Location: Scotland

Good data, maukka – thank you! Thumbs Up

Your Sanyo GA results are pretty close to some datasheet-bashing I did in an old CPF post. Just in case anyone finds the cold-weather discussion in that thread useful, here it is:

http://www.candlepowerforums.com/vb/showthread.php?415498-Cold-temperatu...

THX
Offline
Last seen: 2 years 10 months ago
Joined: 10/26/2018 - 00:03
Posts: 4
Location: TT

Molicel’s datesheet can be written to a minimum of -40 degrees discharge.

I heard that their batteries are designated for use in outer space technology.