P42 fits, we tested that. Length variation is no issue for this pack.
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Hi, which 21700 Cells are the best If you Not in the UK for the Pack?
High drain cells, 15 to 30A continous draw.
You pick the cell with the highest capacity and a high drain value. A high continuous drain needs to prioritised. Cells with high capacity and high continuous drain are usually expensive and low in stock.
For high capacity, Molicel M50A and Samsung 50G are great for up to about 10A each max. Samsung 50E is pretty good up to about 7A.
For around 4000mAh, but higher current handling, Molicel P42Aās are great for up to about 25A each. Samsung 40Tās are good too.
For up to about 35A each the 3000mAh Samsung 30T canāt be beat.
As you can see, you can have high capacity or a high current rating. You canāt have both at the same time. Though there are some cells with good levels of each like the Molicel P42A.
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Right, that is my Problem. The only one is the
Molicel INR21700-M50A 4800mAh - 20A
But Not in Stock at Europe.
And the 40T of samsung has āonlyā 4000mah.
I wait dir the Molicel at nkon
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A lot depends on how much current you are drawing from each cell. At higher current levels the Samsung 40T will run for longer than the Molicel M50A (or Samsung 50G, 50E).
The capacity rating is measured when the cell is discharged at less than 1A. It doesnāt tell you how well the cell will perform when much above that.
The ultra-high capacity cells are a lot less efficient than the cells with higher current ratings (but lower capacity) and that low efficiency means their voltage sags a lot when used near or above their rating and that shortens their running time.
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Thanks for the answer, thatās exciting.
Just for my better understanding, I have a continuous discharge of 70A the molicell efficiency is ok with 7P 140A battery max. but I have a discharge of 70A with the Samsung 50E with 7P 70A battery max they sonst go so long as if I am using the 40T. have I understood that correctly
Iām surprised how bad the 50E is vs. P42A in actual energy delivered.
You rate them as:
P42A: Total energy delivered down to 3.2V at 10A continuous = 12.4Wh
50E: Total energy delivered down to 3.2V at 10A continuous = 12.2Wh
Is it because the 50E is a pre-production sample? Did they get any better later on?
Seems like the 50E has to be discharged at something tiny like 5 amps to make it worth at all. 
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Iām not sure I understand you but here goesā¦
Using those 50Eās at 10A/cell will probably give you about the same range as using 40Tās. That discharge current level is around the crossover point where one will be a better performer than the other.
But since the 40T will be running at a lot lower than its rating that helps to ensure good overall life. I would recommend using the 40T for that reason.
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No, they did not get better. That is how they perform. This is also typical behavior when using a cell at near or over its ratingā¦any cell.
A big issue is that ultra-high capacity batteries have high internal resistance. That causes a lot of voltage sag so you reach the low voltage cutoff of your ESC sooner. This voltage sag can easily wipe out any advantage in capacity the 50E has over other cells.
The 50E is also one of the worst performing ultra-high capacity 21700ās, along with the 48G. TBH, and with no disrespect towards those who use it, I think itās a terrible choice for esk8 use. Other cells like the 50E2, 50E3, M50A, and 50G hold their voltage up better and give you more running time. None of them are great performers above about 10A though.
Yes, the 50E is best used at only up to about 5A-7A. At above that the high-performance 4000mAh (approx.) cells like the P42A and 40T are a better choice due to their lower internal resistance (which means less voltage sag).
We all do it but comparing capacity specs is a terrible way to choose a cell unless you are discharging at only an amp or two. The ānominalā capacity spec is typically measured at under one amp and tells you very little about how the cell will perform at higher discharge levels.
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I cant wait to see where the Tesla Model 3 cell fits into this lineup!
Yeah I am working on an opinion piece that goes into cell efficiency vs run time, and how that should determine how we select cells.
Itās pretty much just going to be a summary of a bunch of things that @Battery_Mooch has been saying for years, that I am only just recently learning since he has joined our community
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bump 
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On the assembly line today.
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On the sketchboardā¦
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Have you finalized that product? Iām looking for BMS to fit into 50mm x 154mm space and capable of 16s. canāt find any with vesc support or with Bluetooth at least.
We have a VESC BMS coming in next week. It will still take 2-3 more weeks until we will offer it on the website. 36*130mm, CAN linked to VESC motor controller, 18S capable.
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Whatās the max charging amps?
Also, price, roughly?
Iām tempted to replace a ltt bms with this on a battery being done now.
Maybe keep the wires removable so i can put this in when it releasesā¦
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