thunderheart
100 W
Hi guys! This testing is without comparison because the batteries are not from the same league, but I think it's still interesting to look at them. The cells are Sanyo NCR20700B 4250mAh, Samsung INR21700-48G 4800mAh and Queen Battery QB21700 4000mAh. As you see they differ in size and in capacity.
The cells were bought from Queen Battery, a Chinese supplier of genuine batteries, who specializes mainly on EV and eBike market. Queen Battery has a branch in Europe, but they also work with customers from Americas, Russia, etc… They also have their own brand cells line and one them you will see in this test.
As always, I've tested with ZKETECH EBC-A20 and a self-made battery holder. It's a PC-connected battery tester supporting 4-wire measuring and discharging at up to 20A.
I've followed all the prescriptions of the IEC61960-2003 standard concerning battery's capacity measurement. Before each discharging cycle each battery was charged at standard current mentioned in its datasheet to 4.2V (cut-off at 0.1A, which is the lowest supported by EBC-A20). Before each discharging or charging i've held a 1-1.5hrs pause. The environment temperature was 20-25°C (21-23°C to be honest).
Discharge cut-off voltage was 2.5V for Sanyo and Samsung and 2.75V for Queen Battery (following their datasheets). Discharging currents were 15A, 12A, 9.6A, 5A and 0.2C which was 0.80A for Sanyo and Queen Battery and 0.96A for Samsung.
Sanyo NCR20700B
This cell's marking is SANYO L NCR20700B 7709. The letter L means that it was made in Japan by Sanyo Energy Higashiura Co. Here is its datasheet.
The main specs:
Rated capacity: 4000mAh (at 20°C)
Capacity (min): 4050mAh (at 25°C)
Capacity (typical): 4250mAh (at 25°C)
Discharge cut-off voltage: 2.5V
Max continuous discharge current: 15A (suggested, not mentioned directly in the datasheet)
Standard charging current: 2A
Max charging current: N/A
Charge end voltage: 4.20V
Measured dimensions of the cell: 20.2 x 70.2mm (DxH)
Max continuous discharge current and 0.2C current in Amps are not specified in the datasheet, so i took the first as 15A based on the second page of the datasheet and the 0.2C current as 0.8A based on the rated capacity of 4000mAh.
So let's take a look at the results:
The curves look pretty nice, without sudden falls and the capacity remains above the 4000mAh point even at 15A. Almost 13Wh at 15A is a brilliant result i think. At 0.2C (0.8A) the capacity was 4273mAh/15.5Wh which is slightly higher than the typical capacity.
Queen Battery QB21700
This cell has no marking on its heat shrink tube, but has a sticker with the most important information about the cell and a link to the Queen Battery's website. Here is its datasheet.
The main specs:
Normal capacity: 4000mAh (at 0.2C)
Capacity (min): 3900mAh (at 0.2C)
Discharge cut-off voltage: 2.75V ± 0.05V
Max continuous discharge current: 12A
Standard charging current: 2A
Max charging current: 2A
Charge end voltage: 4.20V ± 0.03V
Measured dimensions of the cell: 21.6 x 70.9mm (DxH)
The specs are nice except the discharge cut-off voltage. The 2.75V cut-off means that if you are going to add a protection PCB to this cell you will have to find a suitable one, because the majority of PCBs are set to 2.5 or even 2.4V. But let's look at the results:
At 0.2C (0.8A) it shows 4060mAh/14.93Wh - better than declared, but the 0.8A and 5A curves are not that nice as i'd like them to be. They are falling in the end. At 0.8A the sudden fall starts at 3.35V and when discharging at 5A - at 3.2V. But everything changes at higher currents - the curves at 9.6A and 12A are very close to each other and very different from those at 5A and 0.8A. I have done the tests several times but the curves were the same - beautiful curves at 12A and 9.6A and ugly ones at 5A and 0.8A. In fact this battery is better at higher currents than at 5A or lower.
Samsung INR21700-48G
This cell has the same size as the QB21700, but is rated at 4800mAh. The cell's marking is: INR21700-48G SAMSUNG SDI M5-1. Here is its datasheet.
The positive pole of this cell is a bit lower than the heat shrink tube (about 1mm) which results in bad or no contact in slot chargers. I had to spend 2-3 minutes with each charger trying to pose the battery for having a contact. I don't know it's the problem of my cell or the other INR21700-48Gs suffer too. I've tried to show the difference in a shot, but i'm not sure it's easy too see on the photo:
The main specs:
Capacity (min): 4700mAh (at 0.96A discharge)
Capacity (typical): 4800mAh (at 0.96A discharge)
Discharge cut-off: 2.5V
Max continuous discharge current: 9.6A (not for cycle life)
Standard charging current: 1.44A
Max charging current: 4.8A (not for cycle life)
Charging end voltage: 4.20V
Measured dimensions of the cell: 21.1 x 70.5mm (DxH)
The first thing i don't like about this cell is its Standard charging current which is only 1.44A (0.3C). It takes 5 hours to charge it! The second thing is its max discharge current of 9.6A. It's not too low, but i'd like it to be higher. So let's take a look at Samsung's results:
The curves seem very nice to me, especially at 9.6A. At 0.2C (0.96A) the capacity was 4845mAh, higher than declared. At 9.6A it gave out almost 4750mAh which is a good result.
CONCLUSION
Sanyo NCR20700B is a brilliant cell, there is nothing to add.
Queen Battery QB21700 was a surprise for me with its strange behavior at mid and low currents and excellent curves at high currents. It's a good cell if you are OK with 2.75V cut-off voltage.
Samsung disappointed me with its low charging current. 5hrs to charge a cell? Come on, guys... And also it's positive pole which sits deep below the heat shrink... I dunno, i didn't like this cell. Yeah, the curves are fine, but i'd better go with two previous cells.
What about you guys? What do you think? Maybe i'm just too loyal to Sanyo and too strict with Samsung?
The cells were bought from Queen Battery, a Chinese supplier of genuine batteries, who specializes mainly on EV and eBike market. Queen Battery has a branch in Europe, but they also work with customers from Americas, Russia, etc… They also have their own brand cells line and one them you will see in this test.
As always, I've tested with ZKETECH EBC-A20 and a self-made battery holder. It's a PC-connected battery tester supporting 4-wire measuring and discharging at up to 20A.
I've followed all the prescriptions of the IEC61960-2003 standard concerning battery's capacity measurement. Before each discharging cycle each battery was charged at standard current mentioned in its datasheet to 4.2V (cut-off at 0.1A, which is the lowest supported by EBC-A20). Before each discharging or charging i've held a 1-1.5hrs pause. The environment temperature was 20-25°C (21-23°C to be honest).
Discharge cut-off voltage was 2.5V for Sanyo and Samsung and 2.75V for Queen Battery (following their datasheets). Discharging currents were 15A, 12A, 9.6A, 5A and 0.2C which was 0.80A for Sanyo and Queen Battery and 0.96A for Samsung.
Sanyo NCR20700B
This cell's marking is SANYO L NCR20700B 7709. The letter L means that it was made in Japan by Sanyo Energy Higashiura Co. Here is its datasheet.
The main specs:
Rated capacity: 4000mAh (at 20°C)
Capacity (min): 4050mAh (at 25°C)
Capacity (typical): 4250mAh (at 25°C)
Discharge cut-off voltage: 2.5V
Max continuous discharge current: 15A (suggested, not mentioned directly in the datasheet)
Standard charging current: 2A
Max charging current: N/A
Charge end voltage: 4.20V
Measured dimensions of the cell: 20.2 x 70.2mm (DxH)
Max continuous discharge current and 0.2C current in Amps are not specified in the datasheet, so i took the first as 15A based on the second page of the datasheet and the 0.2C current as 0.8A based on the rated capacity of 4000mAh.
So let's take a look at the results:
The curves look pretty nice, without sudden falls and the capacity remains above the 4000mAh point even at 15A. Almost 13Wh at 15A is a brilliant result i think. At 0.2C (0.8A) the capacity was 4273mAh/15.5Wh which is slightly higher than the typical capacity.
Queen Battery QB21700
This cell has no marking on its heat shrink tube, but has a sticker with the most important information about the cell and a link to the Queen Battery's website. Here is its datasheet.
The main specs:
Normal capacity: 4000mAh (at 0.2C)
Capacity (min): 3900mAh (at 0.2C)
Discharge cut-off voltage: 2.75V ± 0.05V
Max continuous discharge current: 12A
Standard charging current: 2A
Max charging current: 2A
Charge end voltage: 4.20V ± 0.03V
Measured dimensions of the cell: 21.6 x 70.9mm (DxH)
The specs are nice except the discharge cut-off voltage. The 2.75V cut-off means that if you are going to add a protection PCB to this cell you will have to find a suitable one, because the majority of PCBs are set to 2.5 or even 2.4V. But let's look at the results:
At 0.2C (0.8A) it shows 4060mAh/14.93Wh - better than declared, but the 0.8A and 5A curves are not that nice as i'd like them to be. They are falling in the end. At 0.8A the sudden fall starts at 3.35V and when discharging at 5A - at 3.2V. But everything changes at higher currents - the curves at 9.6A and 12A are very close to each other and very different from those at 5A and 0.8A. I have done the tests several times but the curves were the same - beautiful curves at 12A and 9.6A and ugly ones at 5A and 0.8A. In fact this battery is better at higher currents than at 5A or lower.
Samsung INR21700-48G
This cell has the same size as the QB21700, but is rated at 4800mAh. The cell's marking is: INR21700-48G SAMSUNG SDI M5-1. Here is its datasheet.
The positive pole of this cell is a bit lower than the heat shrink tube (about 1mm) which results in bad or no contact in slot chargers. I had to spend 2-3 minutes with each charger trying to pose the battery for having a contact. I don't know it's the problem of my cell or the other INR21700-48Gs suffer too. I've tried to show the difference in a shot, but i'm not sure it's easy too see on the photo:
The main specs:
Capacity (min): 4700mAh (at 0.96A discharge)
Capacity (typical): 4800mAh (at 0.96A discharge)
Discharge cut-off: 2.5V
Max continuous discharge current: 9.6A (not for cycle life)
Standard charging current: 1.44A
Max charging current: 4.8A (not for cycle life)
Charging end voltage: 4.20V
Measured dimensions of the cell: 21.1 x 70.5mm (DxH)
The first thing i don't like about this cell is its Standard charging current which is only 1.44A (0.3C). It takes 5 hours to charge it! The second thing is its max discharge current of 9.6A. It's not too low, but i'd like it to be higher. So let's take a look at Samsung's results:
The curves seem very nice to me, especially at 9.6A. At 0.2C (0.96A) the capacity was 4845mAh, higher than declared. At 9.6A it gave out almost 4750mAh which is a good result.
CONCLUSION
Sanyo NCR20700B is a brilliant cell, there is nothing to add.
Queen Battery QB21700 was a surprise for me with its strange behavior at mid and low currents and excellent curves at high currents. It's a good cell if you are OK with 2.75V cut-off voltage.
Samsung disappointed me with its low charging current. 5hrs to charge a cell? Come on, guys... And also it's positive pole which sits deep below the heat shrink... I dunno, i didn't like this cell. Yeah, the curves are fine, but i'd better go with two previous cells.
What about you guys? What do you think? Maybe i'm just too loyal to Sanyo and too strict with Samsung?
