Fast Charger 4.5A Minimotors Thunder

This model cut charging at 66.4V when the selector is at 100% That’s a charge cut-off  4.15V per cell. Opposed to the regular full capacity 67.2 charger with an cut off at 67.2V at the 60V battery pack. This method is similar to what EV hybrid cars do with their Li-ion batteries to ensure longer charging cycles and longer life. And this only at the expense, of a small range reduction.

Most Li-ion are charged to 4.20 V / cell, but each reduction in peak charge voltage of 0.10 V / cell is said to double the life of the cycle. For example, a lithium-ion cell charged to 4.20 V / cell typically delivers 300–500 cycles. If only 4.10V cut-off for each cell, the service life can be extended to 600-1000 cycles; 4.0V / cell should deliver 1,200-2,000 and 3.90V / cell should deliver 2,400–4,000 cycles.

a typical 60V battery for electric scooters consists of traditional lithium-ion with nominal cell voltage of 3.60V 16 cells in series as well as a certain number of these series in parallel to provide enough Ah 

12 rows of cells with fully charged batteries with an traditional charger provide 16 x 4.2V = 67.2V