Easy_Rider said:
I think the INR21700-40T is very interesting in small dimensions of batteries like 10S2P, or 10S3P.
I daubt it, if the 50E, or M50 will have more Wh at this configuration on 250W-350W motors?!
I agree...
Even if the 50E is supposed to be a 5000 mAh 21700 cell, that's probably only true at very low discharge current (like 0.2C or lower).
I mean look at this: https://zeroair.wordpress.com/2018/11/13/liionwholesale-samsung-50e-21700-li-ion-cell-review/
At 10 amps, you get massive sag, and only extract 4200-4400 of the claimed 5000 mAh, and that's on a brand new cell that wasn't yet cooked....
At 10 amps, the voltage sag is massive (due to internal resistance delta V= R x I), and the cell will heat and slowly cook... At 10A, the 50E capacity will rapidly degrade cycle after cycle, and you probably be getting much lower than 4200 to 4400 mAh by that time..
I would much rather invest in the Samsung 40T, they might only have 4000 mAh, but at 10A, you get at least 3900 mAh real, and they won't cooke as much,.
And also, factor in the BMS low voltage cutoff of (let's say 3.3V per cell) and Controller low voltage cutoff, and you really wont extract much real capacity with the samsung 50E, because they sag so much in voltage under load...
For example if you look at capacity at 10A up until you reach 3.3 Volts (LVC) on the Samsung 50E dicharge curve, and you only really extract 2000 mAh of capacity out of the claimed 5000 mAh. Not good...
I see the 50E being used in minimum 10S10P packs for ebikes that pull max 20A... but that's a 7 kilograms (15.4 pounds) battery at least to lug around...
Matador