Would it be fair to say the max MAH for
18650 =3400mah
26650= 5500mah
Any battery claiming to be above those figures should be avoided as even the very best manufacturers haven’t achieved cells above those capacities yet.
(this eliminates a great number *.fire & green wraps)
You are nearly correct.
Use this table: List of tested batteries
Click on the header of the 0.2A column to sort with highest capacity first.
Then you can select battery size in the size column and see the largest capacity I have seen.
Pretty much.
3500mah is the 18650 limit with cells such as the LG MJ1 and and Samsung 35E. I think there was a new cell labeled a 3600, but it actually measured closer to 3500.
5500mah is the limit for 26650 although Keeppower used 6000 on their older label. These PLB cells actually measure around 5750mah.
So any 18650 higher than 3600mah and any 26650 higher than 6000mah are probably misrepresenting themselves.
PS, I think the highest capacity 21700 is 5200mah, but new ones are popping up all the time.
Thank you for the review and comments.
I have a few of them which I got pretty cheap and given the high current I’m thinking of using them to make a pack for my 18V chainsaw.
Upon 1A testing, the record capacity among 10 tested cells was 5991mAh, which is pretty nice.
So instead of using 5S4P 18650s (which was getting me near 12Ah) I’m willing to sacrifice them to try a 5S2P setup with this type of cell.
Pound for pound (volume to volume) the 18650 and 21700 from the big 5 Japanese companies have the highest capacity.
Consider that the 26650 has right around double the volume of an 18650 cell. If they made an 26650, which they dont, it would be 7000mah.
I’m guessing the cells they used in the battery pack were not the highest capacity? They tend to use cheaper cells to keep costs down.
Do you? I thought the same about Tesla cars. I assumed they needed low resistance for more power, but they use the highest capacity cells available. The sheer number of cells gave them all the amps they need.
With 20 cells in the chainsaw battery pack, you might not need such high amperage from each cell.
The PLB INR26650-55A is like 2x 18650 mid capacity and power cells. 5S2P is 10 cells, with a maximum continuous power delivery of 60W/each. Thus, 600W continuous maximum gross input power to the motor. I am no expert in chainsaws but that sounds quite lacking. 30 cells could do up to 1800W continuous and be about comfortable at 1500W continuous, which is just ≈2HP anyway. But electric engines have very high amounts of torque at low to mid rpm, and so…
These Makita batteries look quite small, like drill batteries. Still, surprising result. But just a bit.
@JasonWW - true what you say about the volume-capacity ratio: 18650s are the best, but that is due to the heavy investment in them. They are the most used today. 26650s may improve due to the upcoming electric cars.
Also note that the Panasonic 3500mAh 18650 is limited to 10A and I have not seen any in any power tools (and no power tool batteries like 3.5Ah or 7Ah). The best they all use are the Samsung 3000mAh, which by all fair stadards are not really 3000mAh at high current.
@BlueSwordM - yes, higher current instead of higher capacity. This is preferable for any top power tools.
Tesla chose the 21700 because the lack of top tier manufacturers making mass 26650s. I think current production rate of the top manufacturers exceeds 1B 18650 cells / year, while 21700s were already produced in enough quantity for power tools and the additional volume can count a lot.
As for the cooling, from a pure airflow perspective, everything should be fine if properly constructed. Of course, cooling a thinner element is easier than cooling a thick one, but the the heat generated for a similar power drain will be higher for the thinner cell, so no real gain there.
I don’t know if Tesla stated the maximum temperature that is allowed for the used batteries, but I tested an electric car with custom 26650-based pack and there was no overheating heating whatsoever after a 25Km continuous run, same as for Samsung Q cells, while for Sony V3s there was some heating but within the recommended spec limits of the cells.
What do you mean ?
Didn’t the S/X used Panasonic 18650s ?
Yes, they can build their own like for model 3 but that would not be viable for mass production.
PLB makes 26650s, and while their actual market is a ¯\_(ツ)_/¯ to me, for their 50A and 55A cells this is what they claim:
PLB INR26650-55A 3.6V 5500mAh lithium ion cell is high energy li-ion battery for power application, which has been passed The National Mandatory Inspection and widely used in electric motorcycle, elctric tricycle, lead acid replacement, AGV, power station, ESS, PV street light and so on with high safety on design, high consistency, high reliability, and long cycle life on performance. -> Here.
INR26650-50A 3.6V 5Ah NiCoMn(NCM) battery cell for Motorcycle and Tricycle has been successfully qualified with The National Mandatory Inspection , which widely used in electric buses, electric logistics trucks, electric special vehicles, power station, energy storage system and so on with high security, high consistency and high reliability characteristics. -> There.
It looks like PLB is heavily focused on LiFePO4 development, and they're in China. Don't know how much improvement is to be expected. They also definitively won't be in the media.
Tesla decided to foster development of a new cell size just because that fitted their interests. They didn't have any interest in 26650 development, that wouldn't have allowed them to file new patents and blah blah blah.
Yes, early vehicles used the Panasonic 18650B 3400mah, but several years ago they were evaluating new sizes and started building the Gigafactory. They started out with the plan to build 20700 and then decided 21700 would be better. Once they built their own factory they don’t care about 26650 availability.
Maybe you mean post 211? I still have not heard of any OEM vehicles (like passenger cars) using the 26650. Of course, I am not in this field so there is a lot I don’t know.
PS, those quotes from PLB sound like typical marketing speak to sell batteries. Are they saying their cells can be used for those things or that they are used for those things. There is a big difference. I would love to learn about OEM vehicles using the 26650.