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
- Capacity according to the manufacturer: 5.800mAh
- 2,30 pp incl. shipping
Power ICR18650
- Capacity according to the manufacturer: 4.500mAh
- 1,91 pp incl. shipping
Ultrafire SJ 18650
- Capacity according to the manufacturer: 6.000mAh
- 2,50 pp incl. shipping
Ultrafire DT 18650
- Capacity according to the manufacturer: 8.800mAh
- 1,73 pp incl. shipping
GTF TR 18650
- Capacity according to the manufacturer: 9.800mAh
- 2,26pp incl. shipping
GTF TR 18650 "Gelb"
- Capacity according to the manufacturer: 9.900mAh
- 1,06 pp incl. shipping
GTF TR 18650 "Rot"
- Capacity according to the manufacturer: 9.900mAh
- 1,64 pp incl. shipping
GTL ICR18650
- Capacity according to the manufacturer: 12.000mAh
- 1,85 pp incl. shipping
GTL ICR18650
- Capacity according to the manufacturer: 12.000mAh
- 1,85 pp incl. shipping
"Li-ion battery" TR 18650
- Capacity according to the manufacturer: 4.900mAh
- 2,05 pp incl. shipping
unbranded / YCDC LIR 18650
- Capacity according to the manufacturer: 2.800mAh
- 1,55 pp incl. shipping
Dolidada TR 18650
- Capacity according to the manufacturer: 15.000mAh
- 1,56 pp incl. shipping
Kedanone 18650
- Capacity according to the manufacturer: 12.000mAh
- 1,54 pp incl. shipping
eoaneoe LS 18650
- Capacity according to the manufacturer: 9.900mAh
- 1,78 pp incl. shipping
EPGY / Yiquan 18650 "Hell-Blau"
- Capacity according to the manufacturer: 2.400mAh
- 2,00 pp incl. shipping
EPGY / Yiquan 18650 "Dunkel-Blau"
- Capacity according to the manufacturer: 2.800mAh
- 2,49 pp incl. shipping
EPGY / Yiquan 18650 "Gelb"
- Capacity according to the manufacturer: 2.600mAh
- 2,23 pp incl. shipping
EPGY / Yiquan 18650 "Lila"
- Capacity according to the manufacturer: 3.000mAh
- 2,77 pp incl. shipping
EPGY / Yiquan 18650 "Oliv-Grn"
- Capacity according to the manufacturer: 3.400mAh
- 2,93 pp incl. shipping
EPGY / Yiquan 18650 "Orange"
- Capacity according to the manufacturer: 2.200mAh
- 1,75 pp incl. shipping
Samsung ICR18650-22P
- Capacity according to the manufacturer: 2.200mAh
- used, from eBike akkupack, just fo
Panasonic NCR18650 PF
- 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"
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".
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
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
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.
- 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 theleft the Vapcell YR-1030 to set the resistance values
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
run 1 with 0,41 Ohm = 9 Ampre
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
between this foto here with 7,35A at 2,97V...
...and 4,2A at 1,69V just 2-3 seconds have passed
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.
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
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
(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.
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
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
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
The leaders in lightweight are the black Ultrafire with only 23.2g
about half of the cells tested are around 35g
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
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.
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
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.
Pro:
- 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.
Cons:
- 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.
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.