Poll: how high is the total capacity of all cells?
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< 49.999 mAh
3 60.00%
50.000 - 99.999 mAh
0 0%
100.000 - 199.999 mAh
1 20.00%
200.000 - 299.999 mAh
0 0%
300.000 - 399.999 mAh
0 0%
400.000 - 508.799 mAh
0 0%
508.800 mAh
0 0%
> 508.800 mAh
1 20.00%
Total 5 vote(s) 100%
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China batterie 18650 test - 508.800mAh in 62 cells
Yes, max I've seen so far was 500mAh but it dropped fast to half that after a few cycles.
(05-25-2020, 01:04 PM)ajw22 Wrote: So even a very conservative 500mA charging/discharging is probably overtaxing and killing it.

Because none of the cells have some information about the max current I decided to test this too.
I will try to test the max values of these cells by using a variable resistor with 100 watts, measuring both current and voltage at the same time to adjust the resistor to that value where the voltage isn't dropping too hard.
But therefore we have to wait a little longer because I had to order this resistor and a new multimeter with higher current range.
The resistor arrived today but the multimeter is announced to 6.6.
Today I worked a little on the current test station

I choosed this cell holder because it has some massive metal contacts. The wires are 2,5mm²

very simple configuration. The flexible cable on the right to the movable contact is a 2,5mm² speaker cable

the left clamp is for measuring voltage...

...and the right for current

with the Vapcell YR1030 I measured the restistances at the different postitions...

...and marked them at the variable resistor. One winding is approximately 200 mOhm. The whole resistor has a maximum of 5 Ohm so it should cover a range nearly down to 0,5A just to fit the weakest cells

to test the testing-stand I used the "YCDC" 5.800mAh cell with 3,5Ohm. 0,94A should be OK.

then a short second test with the cell from "Power" and 4.500mAh at 1,0 Ohm. Should be over 3A but the cell couldn't reach this value

More testings are senseless at this time because
1. the left multimeter isn't exact enough to show voltages with decimal place
2. the right multimeter is just for a maximum of 10A

So we have to wait for this test until the new 20A multimeter will be delivered.
Why not consider the UT210E current clamp... its perfect for measuring these types of things and it's affordable.

Its got a 2A, 20A, and 100A range and in 2A range its got 3 places after the decimal 0.001 amps.
(05-27-2020, 08:47 PM)Crimp Daddy Wrote: Why not consider the UT210E current clamp... its perfect for measuring these types of things and it's affordable.

Its got a 2A, 20A, and 100A range and in 2A range its got 3 places after the decimal 0.001 amps.

just saw this too late and ordered a "normal" multimeter instead. But thanks, I think for further usage I will look for the UT210E
(06-04-2020, 05:51 PM)Stefanseiner Wrote:
(05-27-2020, 08:47 PM)Crimp Daddy Wrote: Why not consider the UT210E current clamp... its perfect for measuring these types of things and it's affordable.

Its got a 2A, 20A, and 100A range and in 2A range its got 3 places after the decimal 0.001 amps.

just saw this too late and ordered a "normal" multimeter instead. But thanks, I think for further usage I will look for the UT210E

I own like 6-7 meters and still feel like there is no such thing as too many meters... I would order that one anyway because they do different things.

Regular meter for voltage
Clamp meter for current.
Used together you can calculate power

Current clamps are highly useful and convenient.  You dont have to break the line, and unlike a regular meter, wont suffer from burden voltage when trying to take a current reading.  

On top of all that, regular meters generally tap out at around 10 amps... so they are limited in their usefulness.
Stefanseiner likes this post
I use one meter and it's a very accurate one, but I don't need to measure current over 10A, so there's no problem with that limitation. I have also a junk meter just in case of emergencies (primary one not working).
The 20A multimeter arrived earlier than expected and therefore I was able to finish the test.

02 - The candidads

Here is a brief introduction to the test candidates
YCDC / Skywolfaya  
[Image: phoca_thumb_l_China_Akku_18650_Test_12_d...idaten.jpg]
  • Capacity according to the manufacturer:  5.800mAh  
  • 2,30€ pp incl. shipping
Power    ICR18650   
[Image: phoca_thumb_l_China_Akku_18650_Test_13_d...idaten.jpg]
  • Capacity according to the manufacturer:  4.500mAh  
  • 1,91€ pp incl. shipping
Ultrafire    SJ 18650 
[Image: phoca_thumb_l_China_Akku_18650_Test_14_d...idaten.jpg]
  • Capacity according to the manufacturer:  6.000mAh  
  • 2,50€ pp incl. shipping
Ultrafire    DT 18650 
[Image: phoca_thumb_l_China_Akku_18650_Test_15_d...idaten.jpg]
  • Capacity according to the manufacturer:  8.800mAh  
  • 1,73€ pp incl. shipping
GTF    TR 18650   
[Image: phoca_thumb_l_China_Akku_18650_Test_16_d...idaten.jpg]
  • Capacity according to the manufacturer:  9.800mAh  
  • 2,26€ pp incl. shipping
GTF    TR 18650 "Gelb"  
[Image: phoca_thumb_l_China_Akku_18650_Test_17_d...idaten.jpg]
  • Capacity according to the manufacturer:  9.900mAh  
  • 1,06€ pp incl. shipping
GTF    TR 18650 "Rot"   
[Image: phoca_thumb_l_China_Akku_18650_Test_18_d...idaten.jpg]
  • Capacity according to the manufacturer:  9.900mAh
  • 1,64€ pp incl. shipping
GTL    ICR18650   
[Image: phoca_thumb_l_China_Akku_18650_Test_19_d...idaten.jpg]
  • Capacity according to the manufacturer:  12.000mAh  
  • 1,85€ pp incl. shipping
GTL    ICR18650   
[Image: phoca_thumb_l_China_Akku_18650_Test_20_d...idaten.jpg]
  • Capacity according to the manufacturer:  12.000mAh  
  • 1,85€ pp incl. shipping
"Li-ion battery"    TR 18650   
[Image: phoca_thumb_l_China_Akku_18650_Test_21_d...idaten.jpg]
[Image: phoca_thumb_l_China_Akku_18650_Test_22_d...idaten.jpg]
  • Capacity according to the manufacturer:  4.900mAh
  • 2,05€ pp incl. shipping
unbranded / YCDC    LIR 18650   
[Image: phoca_thumb_l_China_Akku_18650_Test_23_d...idaten.jpg]
  • Capacity according to the manufacturer:  2.800mAh  
  • 1,55€ pp incl. shipping
Dolidada    TR 18650   
[Image: phoca_thumb_l_China_Akku_18650_Test_24_d...idaten.jpg]
  • Capacity according to the manufacturer:  15.000mAh  
  • 1,56€ pp incl. shipping
Kedanone    18650   
[Image: phoca_thumb_l_China_Akku_18650_Test_25_d...idaten.jpg]
  • Capacity according to the manufacturer:  12.000mAh  
  • 1,54€ pp incl. shipping
eoaneoe    LS 18650   
[Image: phoca_thumb_l_China_Akku_18650_Test_26_d...idaten.jpg]
  • Capacity according to the manufacturer:  9.900mAh  
  • 1,78€ pp incl. shipping
EPGY / Yiquan    18650 "Hell-Blau"   
[Image: phoca_thumb_l_China_Akku_18650_Test_27_d...idaten.jpg]
[Image: phoca_thumb_l_China_Akku_18650_Test_28_d...idaten.jpg]
[Image: phoca_thumb_l_China_Akku_18650_Test_29_d...idaten.jpg]
  • Capacity according to the manufacturer:  2.400mAh  
  • 2,00€ pp incl. shipping
EPGY / Yiquan    18650 "Dunkel-Blau"  
[Image: phoca_thumb_l_China_Akku_18650_Test_30_d...idaten.jpg]
  • Capacity according to the manufacturer:  2.800mAh  
  • 2,49€ pp incl. shipping
EPGY / Yiquan    18650 "Gelb"   
[Image: phoca_thumb_l_China_Akku_18650_Test_31_d...idaten.jpg]
  • Capacity according to the manufacturer:  2.600mAh  
  • 2,23€ pp incl. shipping
EPGY / Yiquan    18650 "Lila"   
[Image: phoca_thumb_l_China_Akku_18650_Test_32_d...idaten.jpg]
  • Capacity according to the manufacturer:  3.000mAh  
  • 2,77€ pp incl. shipping

EPGY / Yiquan    18650 "Oliv-Grün"  
[Image: phoca_thumb_l_China_Akku_18650_Test_33_d...idaten.jpg]
  • Capacity according to the manufacturer:  3.400mAh  
  • 2,93€ pp incl. shipping

EPGY / Yiquan    18650 "Orange"  
[Image: phoca_thumb_l_China_Akku_18650_Test_34_d...idaten.jpg]
[Image: phoca_thumb_l_China_Akku_18650_Test_35_d...idaten.jpg]
  • Capacity according to the manufacturer:  2.200mAh  
  • 1,75€ pp incl. shipping

Samsung    ICR18650-22P
[Image: phoca_thumb_l_China_Akku_18650_Test_36_d...idaten.jpg]
[Image: phoca_thumb_l_China_Akku_18650_Test_37_d...idaten.jpg]
  • Capacity according to the manufacturer:  2.200mAh  
  • used, from eBike akkupack, just fo

Panasonic NCR18650 PF
[Image: phoca_thumb_l_China_Akku_18650_Test_38_d...idaten.jpg]
[Image: phoca_thumb_l_China_Akku_18650_Test_39_d...idaten.jpg]
  • Capacity according to the manufacturer:  2.900mAh  
  • used, from eBike akkupack, just for comparison

03 - the Tests

In order to check the battery cells and record all relevant values, I carried out several tests.
The test procedures are briefly described here in detail.

1. Determine weight
All battery cells were weighed individually with a mini-scale and the weight noted.
You can find all the values for this in the next point "04 - Results"
[Image: phoca_thumb_l_China_Akku_18650_Test_40_T...fahren.jpg]

2. Inner resistance
Since the internal resistance of Li-ion batteries is very small (in the mOhm range) and normal multimeters usually do not work with sufficient accuracy, measurements were taken with the "Vapcell YR-1030".

[Image: phoca_thumb_l_China_Akku_18650_Test_41_T...fahren.jpg]
3. Capacity test
The capacity test was carried out with the maximum settings of the LiitoKala Lii 500 Enineer, which corresponds to 1.0A charge current and 0.5A discharge current
[Image: phoca_thumb_l_China_Akku_18650_Test_42_T...fahren.jpg]
the temperature was determined using an infrared thermometer, in each case 30 minutes after the start of the charging process and 30 minutes after the start of the discharging process
[Image: phoca_thumb_l_China_Akku_18650_Test_43_T...fahren.jpg]
here is a compilation of the results. Boring to look at, but because of the display lighting no smart photos were possible, so as a video.

4. Current test
In addition to the capacity, the maximum discharge current also plays an important role and determines the possible use of the respective battery.
Here is the experimental setup for measuring the current.
[Image: phoca_thumb_l_China_Akku_18650_Test_44_T...fahren.jpg]
  • an adjustable load resistor in the middle (green, round). It can be loaded up to 100 watts, goes up to 5 ohms and is adjustable in ~ 200mA steps.
  • Since I test 62 cells, a fan cools the resistor
  • the right multimeter is connected in series to the battery holder and measures the current, it can be loaded up to 20A
  • the middle multimeter is connected in parallel and measures the voltage. If the test battery is loaded too much, the voltage drops and you can see that
  • on the left the Vapcell YR-1030 to set the resistance values
[Image: phoca_thumb_l_China_Akku_18650_Test_45_T...fahren.jpg]
The current test was carried out in several runs, in which the resistance values were adjusted again and again in order to approach the maximum discharge current of the cells:
1. run    0,41 Ohm    9,0A
2. run    0,50 Ohm    8,2A
3. run    0,62 Ohm    6,2A
4. run    0,79 Ohm    4,7A
5. run    1,15 Ohm    3,2A
6. run    1,35 Ohm    2,7A
7. run    1,52 Ohm    2,4A
8. run    1,70 Ohm    2,1A
[Image: phoca_thumb_l_China_Akku_18650_Test_46_T...fahren.jpg]
run 1 with 0,41 Ohm = 9 Ampère
[Image: phoca_thumb_l_China_Akku_18650_Test_47.2...ketest.jpg]
First of all: none of the candidates delivered 9A.
A maximum of 8.6A has flowed here, and only for a few seconds because at this current the voltage already breaks down, as can be seen here with the Skywolfaya
[Image: phoca_thumb_l_China_Akku_18650_Test_48_S...ketest.jpg]
between this foto here with 7,35A at 2,97V...
[Image: phoca_thumb_l_China_Akku_18650_Test_50_S...ketest.jpg]
...and 4,2A at 1,69V just 2-3 seconds have passed
[Image: phoca_thumb_l_China_Akku_18650_Test_51_S...ketest.jpg]
here is a short summary of some tests, all with a resistance preset of 0.41 Ohm

the temperature of the resistor is measured repeatedly during the tests. During a test at around 8A, it repeatedly warms up briefly to 36 ° C, but since the individual tests only last between 10 and 30 seconds, the temperature of the resistor settles at around 26 ° C.
[Image: phoca_thumb_l_China_Akku_18650_Test_52_S...ketest.jpg]
For a majority of the China cells, the voltage remained stable between 3.7 and 3.6V at a resistance value of 1.15 ohms, which corresponds to a permanent discharge current of 3.3A

The Doldidada 15,000mAh were particularly catastrophically in the current test, only at 1.7 ohms did the voltage remain stable, which corresponds to 2.1A discharge current
[Image: phoca_thumb_l_China_Akku_18650_Test_64_S...ketest.jpg]

04 - Results

Now for the results.
At the very end there are all values and test results in tabular form for download,
but I would like to point out the highlights for each point.

1. Capacity
The most important thing right at the beginning: Unfortunately, the promised 509,600 mAh are "barely" missed.
The realistic, determined total capacity of all 62 cells together is

74.469 mAh

 manufacturer / capacity manuf. / temp charge / discharge / real cap. / cap. range / cap. avg. / cap. % to manufacturer
[Image: phoca_thumb_l_China_Akku_18650_Test_65_Ergebnisse.jpeg]
(Samsung and Panasonic cells are not included in the calculation of the total values)

The performance range of the test candidates ranges from 2,200mAh (EPGY / Yiquan) to 15,000mAh factory specifications. The Dolidada with the highest data actually has the lowest measured capacity of the entire test field with only 418mAh.
The highest measured value is 3,161mAh and comes from the EPGY with the stated 3,400mAh.
[Image: phoca_thumb_l_China_Akku_18650_Test_66_Ergebnisse.jpeg]
[Image: phoca_thumb_l_China_Akku_18650_Test_83_K...000mAh.jpg]
Seen on average over 62 cells, the measured capacity is 14.6% of what the manufacturers promise.
Special features here:

  •     the Dolidada 15,000mAh is a real 3.3% of what is advertised - which is just a brazen scam
  •     In the case of cheap Chinese batteries, the red, unbranded cells with 2,800 mAh and at least 45.5% real capacity occupy the highest value
  •     with the more expensive cells from "EPGY" the model with 2.800mAh rated with 102.3% measured performance is even a little above the manufacturer's specifications
[Image: phoca_thumb_l_china_akku_18650_test_84_ergebnisse.jpeg]
Compilation of all capacity test results

2. Internal resistance Ri
The internal resistance measurement shows that the Chinese cells almost have similarly high values of around 45 to 55 mOhm. The deviations within the four models are largely small.
Special features when measuring resistance:
  • the "eoaneoe" has an outlier with 148 mOhm, which can be seen as an indication of poor quality control and / or fluctuations in production
  • with 20 mOhm, the EPGY 2.800mAh have the lowest internal resistance value and, which is partly due to this, the highest maximum discharge current
[Image: phoca_thumb_l_China_Akku_18650_Test_68_Ergebnisse.jpeg]
For the remaining candidates, the range of internal resistance for the four cells of one type was very small, which speaks against the use of recycled brand cells and for in-house production with an approximately constant quality level.

3. Weight
There are reports in which China cells have been filled with sand to increase the weight and thereby obscure the low use of materials.
Obviously, this does not seem to be the case with the models tested here, because all cells are well below the approx. 44 - 47g of branded cells.
Here is the Panasonic NCR18650PF
[Image: phoca_thumb_l_China_Akku_18650_Test_111_Gewicht.jpg]
The leaders in lightweight are the black Ultrafire with only 23.2g
[Image: phoca_thumb_l_china_akku_18650_test_80_ergebnisse.jpeg]
about half of the cells tested are around 35g
[Image: phoca_thumb_l_China_Akku_18650_Test_100_Gewicht.jpg]
It is also interesting that the weight range is very small for all test candidates, which also speaks for a roughly constant production quality.

Exception: the eoaneoe, which already had an outlier due to internal resistance
[Image: phoca_thumb_l_China_Akku_18650_Test_71_Ergebnisse.jpeg]
4. Temperature development
The temperature was measured using an infrared thermometer of the individual cells during charging (1A charging current) and during the discharging process (0.5A), in each case 30 minutes after the start.
There were no real abnormalities in the sense of "heaters", ie extreme heat development. Quite the contrary was the case, all cells remained very cool.
At 42 ° C the GTL 12,000mAh became the hottest, the Dolidada 15,000 remained the coolest at 29 ° C.
[Image: phoca_thumb_l_china_akku_18650_test_82_ergebnisse.jpeg]
5. price
Since the price of some batteries was only including postage, for others the shipping costs were calculated separately, I converted all prices into € per cell including shipping (1€ = 1.13 USD).
In addition, a conversion to € per 1,000mAh measured. I think this information is quite important, because it also shows whether the cheap China batteries are bargain or not, despite their low capacity.

the most expensive per 1,000 mAh are the Ultrafire SJ with 4.64 €
Although the Dolidada have the second cheapest single cell price at € 1.56 / unit, thanks to their super-low real capacity they are ultimately the second most expensive cell by price / 1,000 mAh.
the most expensive single price is the EPGY 3,400mAh with € 2.93
the cheapest price after € / mAh are the EPGY 2,200mAh with € 0.83 / 1,000mAh
[Image: phoca_thumb_l_china_akku_18650_test_85_ergebnisse.jpeg]

6. Table with all measured values
Here I would like to provide all measured values in tabular form as a PDF

-> Download (13KB)

05 - Conclusion

This test is definitely not 100% accurate and scientifically, the measuring devices are also not professional laboratory devices,
but I only do it for fun, have no affiliate links, no YouTube advertising and no other marketing.

I had two intensions with this test:
  • are there any usable cheap china batteries?
  • Share the knowledge with others

The question of usable China batteries cannot be answered simply with yes or no.
It depends on what purpose you need batteries for, on what budget and what everyone judges to be good.

  • with a few exceptions, the quality of the cells seems to be constant, so there are only slight fluctuations in weight, internal resistance, temperature development and real capacity
  • the temperature development is harmlessly low, also because the electricity supply is very limited
  • Favorable unit price of 1.54 € / cell including shipping
  • Real capacity values around 1200mAh like some of the China cells are fine for small applications such as wildlife cameras, simple flashlights, battery fans, smartphone power walls etc.
  • the cells of EPGY all have approximately the capacities which are also indicated. Three out of six are even above, three just below.

  • it cannot be guaranteed that the same battery cells that are produced in a year will still have the same values as tested here
  • The low discharge current of all low-cost cells (except the EPGY) severely limits the use of the cells
  • converted to € / mAh, the price of cheap cells is very high and sometimes more expensive than for branded cells
  • Real capacity values of around 500mAh as with the really bad China cells are completely unusable and every laptop cell, however exhausted, has even more remaining capacity.
  • Long-term durability, availability and consistent quality are uncertain

To summarize my conclusion:
The cheap China cells with less than 1,000mAh are actually expensive waste and nobody should buy and support something like this.

[Image: phoca_thumb_l_China_Akku_18650_Test_88_K...000mAh.jpg]
For the rest:
If you are aware that in the best case you get around 1200mAh and
if you only need batteries for certain mini-applications such as wildlife cameras etc. and
if you don't find better branded batteries in the price comparison € / mAh
then cheap China batteries from Ultrafire, GPL and Co. may be an option.

However, for just a little more money you get a significant increase in performance, s. EPGY cells. However, it would also have to be clarified here whether their quality is also constant and whether they are manufactured continuously, because at the time of the test end all models were already shown as "not available".
And if we move around € 3 / cell, there are also alternatives from well-known brands such as Sony, LG Chem, Sanyo, Samsung or Panasonic and others. In contrast to the cheap cells, you can rely on the information regarding capacity, discharge current and also regarding safety devices. The values of the cells are often somewhat better than those specified by the manufacturer.

For my part, in any case, I cannot make a recommendation for one of the cells presented here.
hope you left detailed negative feedback wherever you bought these.
i often thought of getting a bunch of folks together to purchase,test,and neg these junk sellers on ebay.
i suspect ebay has financial interest in these high volume sellers or they could simply nuke any listing of 18650 cells with a capacity claim over 3600mah as fraudulent.

(05-25-2020, 12:34 PM)Overmind Wrote: There are 2 types of ultra-fakes I usually encounter:

Very fakes very light ones that yield between 40 and 200 mAh.
Normal fakes that are a little heavier (still way under 4x grams) that can initially yield 300-500mAh.
I can post the exact weights if needed.

Note that yields drop very fast mostly after just a few uses.

I can use these only on very low power lasers (<100mWs).

there is another class.
rewrapped salvage cells.
totally random capacities.
i suspect their criteria for rewrapping is has some voltage and is roughly 18x65mm.
these have a fancy plate and button top installed to hide the spotwelds.
Great detailed research! The problem is that these cells will never go away, when 1 seller gets kicked off ebay or aliexpress, there's 2 to take their place. Luckily, we all know better than to buy these cells, but the general public doesn't, and there is no one looking out for them, especially the marketplaces that make money off of them. I have to admit, the first 18650 I ever bought was an Ultrafire that ended up being a rewrapped Sanyo heater (the irony). I also bought some SkyWolfs and the purple batteries with the horse on them before going Genuine (and then Generic).

While the batteries in your test are obvious duds, I have to say there are 6 categories of Chinese batteries.
1) Genuine equivalents like BAK and ASO.
2) Useable, but last 400 cycles like CJ, THLD, and ReVolt cells.
3) Bad quality cells that degrade very quickly, have high IR from the factory, tend to leak, etc. YLE, HE, EPT, etc.
4) Rewrapped end-of-life genuine cells (Ultrafire)
5) Ultra Low capacity, few cycle cells (Also Ultrafire)
6) Cells with sand in them. (Great Youtube fodder, but ultra rare)
Check out my long-term capacity test of 18650s: https://secondlifestorage.com/showthread.php?tid=6868

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