Without a lot more information
(controller settings, battery voltage under load, current draw and temperatures of the motor and controller etc.) it is difficult to know what is causing the problem, but if the motor is slowing down, it may be due to one of the following:
- The motor is getting too hot (or the "Motor temperature limited(°C)" is set too low)
- The controller is getting too hot
- The battery voltage is dropping too low under heavy load
- The 50% speed limit voltage (V) is set too high
The internal Sine Wave controllers used on the GM hub motors will automatically reduce the current if the battery voltage reaches the minimum voltage setting in order to prevent the battery voltage from going below the set limit, but I'm not sure if your controller does the same.
What does your battery voltage read under load, and how much current is being drawn
(Ampères) when the motor starts to slow down?
I am also confused by one of your previous comments:
I also installed 20 kW of Lithium batteries and there it is full satisfaction, as they recharge in a couple of hours only with my photovoltaic cover.
Is this 20kW of maximum power output, or 20kWh of stored energy?
The maximum Power output that a battery can produce
(measured in W or kW) and the total Energy stored in a battery
(measured in Wh or kWh) are completely different.
A 48V 5Ah LiPo pack with a discharge rating of 90C can physically produce an output of 21.6kW at the maximum rated current
(5 x 90 x 48) for a maximum duration of less than 40 seconds, but it can only hold a maximum of 240Wh
(48 x 5 = 240Wh or 0.24kWh) of stored energy.
What is the actual capacity
(in Ah) and the maximum continuous discharge current
("C" rating) of the "20kW of Lithium batteries" that you have installed?
How much power is generated by your "photovoltaic cover"?
20kWh of
Energy @ 48V would require a battery pack of around 417Ah, and the total area of your "photovoltaic cover" would have to be very large to generate a continuous 10kW of power to enable a charging current in excess of 200 Amps
to fully recharge a battery of that capacity in just "a couple of hours".
Alan