Nice try. Close, but no cigar. 2 x 5S = 10S. 10S = 36v, so 2 x 8Ah 5S gives an 8Ah 36v battery.He means you need two batteries both rated at minimum of 8Ah (amp hours - higher number is better for range).
5S means 5 cells in series meaning your battery pack has five cells in series and also some in parallel to to deliver the higher current.
If you know the voltage of the motor eg: 24V/36V etc, you divide that number by 5 to see what voltage the cells should be.
I think
We used to do that a lot when we wanted batteri3s that could give a bit of power. Lipos can give over 100 amps. 10 years ago, normal lithium batteries were struggling at 15 amps. Lipos are cheaper, but don't last as long. You can charge them with a lipo charger, so no need for a BMS, though you need to be very careful with low voltage control, since there's no cut-off. A voltmeter or lipo alarms are essential. If you already have the lipo charger and alarms from R/C hobby, it's a very cheap way of getting a powerful and light ebike battery.
