18650, 26650 and NP-F batteries and capacities

[-jeff]

Rechargeable lithium ion batteries are becoming common in electronic equipment and camera trapping is no exception. I use the 18650. 26650 and NP-F batteries in many of the camera traps and products we manufacture at TRLcam. The capacity of the cell makes for smaller products with much longer battery life.


A few weeks ago I was looking for something on Amazon and stumbled upon this battery capacity tester. US$7.99 shipping included. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 It looked simple enough, maybe it will work. So, a few days later the UPS made his daily stop and delivered this piece of tech. The package included the board and a couple 7.5 Ohm 5 Watt resistors. This product can be used to test any type of battery and by changing the resistors you can vary the current draw on the battery. It might be interesting to test different brands of AA rechargeable batteries.





The 7.5 Ohm resistors are used to set the current draw of the battery under test. With a 18650 battery voltage of 3.7 Volts, one 7.5 Ohm resistor will put a 500mA load on the battery. Put the two resistors in parallel and it will draw 1 Amp and if you put the resistors in series a 250mA load will be applied to the battery.


After going through my bin of 18650 and 26650 batteries I came up with a few assorted brands and capacities of batteries.





So, I started testing. Here are a few of the results:


Panasonic NCR18650B - printed capacity 3000mAh - tested capacity 2909mAh
EBL BRC18650 - printed capacity 3000mAh - tested capacity 2289mAh
Tenergy 18650 - printed capacity 2600mAh - tested capacity 2208mAh
IMR 18650 - printed capacity 2500mAh - tested capacity 320mAh
LCYYO BRC18650 - printed capacity 3000mAh - tested capacity 1894mAh
Westinghouse INR18650F - printed capacity 3350mAh - tested capacity 2887mAh
LumiTact 18650 - printed capacity 2600mAh - tested capacity 1925mAh
Tenergy ICR18650 - printed capacity 2200mAh - tested capacity 2106mAh
UltraFire BRC18650 - printed capacity 4000mAh - tested capacity 1824mAh


EBL 26650 - printed capacity 5000mAh - tested capacity 5034mAh
Ultrafire 26650 - printed capacity 6000mAh - tested capacity 1745mAh


NP-F550 - printed capacity 2200mAh - tested capacity 1972mAh
NP-F750 - printed capacity 5000mAh - tested capacity 3948mAh
NP-F950 - printed capacity 7900mAh - tested capacity 5293mAh
Inside the NP-F batteries are 18650 cells. The F550 has two cells in series, the F750 has four cells and the F950 has six cells. All NP-F battery packs put out 7.4 Volts.


I had several of the UltraFire 18650 and 26650 batteries in the bin so I tested three of that model battery. They all were way below the manufacturers listed capacity.


It is very difficult to buy genuine batteries on the internet. One of my favorite 18650's has been the Panasonic NCR18650B manufactured in Japan. You can go to AliExpress and see many copies. You can even purchase heat shrink battery skins to make any 18650 into a Panasonic NCR18650. Buyer beware.

[J Formstone]

Wow! Your results are quite an eyeopener. As you say buyer beware.

[-jeff]

UPDATE....

Here is a quick update the battery testing I have done in the last few weeks.

I have been purchasing NP-F style batteries from Amazon for testing and choosing packs that are listed "Amazon's Choice" or packs with a high star rating. Each pack is charged to 100% before testing. The test applies a 450mA load to the pack and records the time required to drain the pack down to 6 Volts or about 10% remaining charge.

Powerextra NP-F960/F970 7.4 Volt, 8800mAh, Amazon's Choice and five stars with 1,602 global ratings.

First test = 6643mAh
Second test = 6130mAh
Third test = 6294mAh

On the inside of the Powerextra are six 18650 cells, each rated at 2000mAh.

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The cells are connected in a 2S3P configuration. So, each cell is 3.7 Volts and 2000mAh. In this configuration the total possible rated mAh would be 6000mAh, 2800mAh less than advertised.

DSTE NP-F970 7.4 Volt, 7900mAh, Amazon's Choice and four and a half stars with 386 global ratings.

First test = 5822mAh
Second test = 5628mAh
Third test = 5589mAh

On the inside of the DSTE are six 18650 cells, each rated at 2200mAh.

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The cells are connected in a 2S3P configuration. So, each cell is 3.7 Volts and 2200mAh. In this configuration the total possible rated mAh would be 6600mAh, 1300mAh less than advertised.

Powerextra NP-F980L 7.4 Volt, 10050mAh, Amazon's Choice and four and a half stars with 34 global ratings. This battery has a micro USB B connector for charging and a USB A connector to use this pack as a power storage device that can be used to charge a cell phone, camera, etc. It also has a charge level meter.

First test = 9710mAh
Second test = 9287mAh
Third test = 9526mAh

I have not taken this battery apart yet but will in the future.

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So far I am impressed with this battery and looking foreword to trying it in a camera trap. I like the ability to charge the pack with a common USB cable. The pack is 3/4" taller than a common six cell NP-F pack.

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Vemico NP-F980/F970 7.4 Volt, 7800mAh, Amazon's Choice and four and a half stars with 203 global ratings. This battery has a micro USB B connector for charging and a USB A connector to use this pack as a power storage device that can be used to charge a cell phone, camera, etc. It also has a charge level meter.

First test = 6211mAh
Second test = 6192mAh
Third test = 6304mAh

On the inside of the Vemico are six 18650 cells, each rated at 2200mAh.

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I pried the Vemico open just enough to see the cell capacity and configuration. The cells are connected in a 2S3P configuration. So, each cell is 3.7 Volts and 2200mAh. In this configuration the total possible rated mAh would be 6600mAh, approximately 1200mAh less than advertised. The pack is 1/2" taller than a common six cell NP-F pack.

More to come.

[-jeff]

Wasabi BTR NP-F960-JWP 7.4 Volt, 8500mAh, Amazon's Choice and four stars with 90 global ratings.


First test = 4292mAh
Second test = 4089mAh
Third test = 4353mAh











I disassembled the Wasabi pack to investigate further. The Wasabi pack has four unlabeled rectangular cells and a couple pieces of steel taped on top. I don't know the purpose of the steel other than to add a little weight to the pack. It serves no electrical purpose.

[Bernardo Segura]

amazing information, thanks!!

[Daryl Dean]

Great information Jeff .. thanks

[-jeff]

UPDATE:


The battery tested was a Vapcell INR26650 5500mAh 3.7 Volt cell. Same testing procedure, a 250mA load over time to draw the cell voltage down to 3 Volts to determine mAh.





I was skeptical about the 5500mAh rating but they were highly rated by other testing sites. Four cells were tested. All tested above the advertised 5500mAh rating with an average of 5662mAh. I'm impressed. They also make many other sizes of lithium ion batteries and I will be ordering and testing some 18650 cells from them.


Two of these in a camera trap should be able to fill a 128gb memory card with images or video.

[-jeff]

Just a quick note.......the capacity tester is also a great way of determining the current draw of your camera trap and will give you a good idea of how long your batteries will last.





Just connect your camera trap to the load terminals observing polarity. In this picture the camera trap would replace the two rectangular resistors.

[-jeff]

So far the only NP-F style battery I have tested that meets or exceeds the manufacturers rating is the NEEWER NW-F970. Rated at 6600mAh and tested at 7200mAh.

I have been asked if the battery could be used to power a flash, but, I have not used a NP-F style for a flash, but I do use two 26650 cells in series with a high current switching regulator to keep the voltage around 6vdc. This works well but keep in mind the SB flash was released in 1997, when the only AA batteries available were carbon zinc, alkaline and Ni-CD. Battery tech has advanced quite a bit in the last twenty four years. These are not high current draw batteries. The SB flash has no current regulation built in and will accept as much current as your supply has to offer. The flash will draw over six amps to recharge the flash caps. The older battery technology would never provide this much power, limiting the heat produced. But, a Li-ion will. This will cause the flash to generate heat with each discharge/charge cycle. If this happens in rapid succession, the flash will be fried. So, when choosing your power supply, use a switching power supply with a current limiting adjustment. The four AA batteries in the flash will put out less than one amp of current. That's a good place to start with your current regulation.


I have a six AA battery NP-F holder here. I'll load it up with fresh AA batteries, test it and post the results here. Years ago when I purchased this I thought this would be a good idea. But then it occurred to me this is the same physical size as a Li-ion NP-F pack. The mAh with AA cells will be a fraction of the mAh with 18650. So, I never used it.




UPDATE:

I loaded the pack with six white Sanyo eneloop AA batteries. All six batteries were about four years old and have been used in Nikon flashes. I wanted to test with six black Panasonic eneloop Pro batteries but I only had four in stock. The white Sanyo eneloop batteries are rated at 1900mAh. So, in a 6S configuration the NP-F pack should have a capacity of 1900mAh. The test ran with a load of 500mA and with a cutoff voltage of 4 volts. The first test resulted in a capacity of 1886mAh. Not bad for older batteries.

The Panasonic eneloop pro is rated at 2450mAh. I ordered a four pack and will test them when they come in.

But.....two genuine Panasonic 18650 batteries in series will produce the the same voltage at 3400mAh than six eneloop AA batteries, taking up a lot less

[reamy]

Have you encountered any other NP-F style batteries that performed exceptionally well in your tests, and do you plan to explore testing newer battery models in the future? Additionally, have you considered using Li-ion batteries with your camera traps, given their potential advantages over traditional AA cells?