Battery model: C91. C99
Nominal voltage: 48V
Capacity: 17.5Ah/20Ah/23Ah
Charge voltage: 54.6V
Watt-hour cappcity:  840Ah/960Wh/1104Wh
Input Interface: DC5521
Output Interface: XT60
With key for lock.

Warning: 
The 17.5Ah  and 20ah battery is only suitable for single motor version of C91 or C99. could not install on Dual motor version. 
If it is used for single motor C91. there is a risk of damaging the battery.

48V 23ah could use for both single and dual motor version.