There are two main types:

1. Bafang motor (as well as the 250 Watt as well the 750 Watt) need a M12 size nut.
2. JB (Jiabo) motor (750 Watt) need a M14 size nut.

Tesla Cells have become a “generic trademark” for bigger cells. 

At present (mid 2023), while there is a huge demand for more energy density for lithium battery, the current 18650 Cell can’t increase much on capacity. 21700 battery power density is better than 18650 batteries. With Tesla embracing these bigger Cells: we all are calling the 21700 cells like “Tesla Cells”. They are just High Capacity Cells.

AFTER regular charging (to 100%) and your led is green, the charger is still delivering a minimal current, so the BMS can do its job. It will balance out the amount of Volts in every cell as good as possible, so they carry all the same/similar amount. This is a slow process, that is why it is advised to leave it hooked up to the charger for a additional 4~8 hours. It is not needed every charge cycle, but it is a bit depending of your use: daily commuter of weekend fun driver? In average you can say 1x every 5~8 charge cycles you have to do a “balance of cells”.

In the attached image you see:

– top: unbalanced; visually its even clear it is not optimal use of the capacity of every cell.

– middle: passive balancing (slowly fill all cells simultaneous the same and when one reaches its maximum stop charging all).

– bottom: active balancing: fill each cell to its max, compare and try to empty the highest a bit and use that energy to top up the lowest a bit. Trying to use optimal the already present energy in your battery-pack.

There is more going on in the background, but this is called balancing.

Short: leave your charger connected for 4~8 hours AFTER indication full (eg. a green light) once every 5 to 8 charge cycles. It will prolong your battery lifetime ; the most expensive & precious part of your ebike.

So by loving ❤ your batt 🔋a bit and maintain it, it will reward you in return with a longer lifetime. 

For the first cycles (with your new LITHIUM -ION Battery) it is always recommended to fully charge 100%

So the BMS (Battery Management System) can properly balance the cells. After, you can charge 80-90% of the total battery capacity if you like, but remember once every a while you always need to repeat a full recharge.