After tuning and some test run following are our results.
Tested range: ~42.89 km (still not empty, should be more than 50% left. Voltage at the end of test is 49V, full charged voltage is 52V and min voltage for this battery should be around 38V)
Maximum speed: 44km/h (1passenger + 1driver) or 40km/h (4passengers + 1driver) (but need time to accelerate, may be up to 15~20s to reach 37~40km/h)
Maximum power at full speed: 3.6kW
Maximum power at start driving: 10kW
Car weight: ~ 1000 kg, not include passengers/driver
Result: Can drive with mild acceleration/cannot climb steep slope (Lack power due to not enough gear ratio)
Following are issue list.
1. Torque is not enough, so at full speed motor only use power for 3.6kW (motor does not has torque to fight the air drag + rolling resistance. But when starting motor use 10kW as at starting the motor efficiency is low so it require a lot of power to starting) Also it cannot climb steep slope.
2. Current meter is now unusable. (It may use 72V system and since the meter is MCU based, so we cannot do much on reverse engineering)