I like what you do… in reference to your battery I don’t think the solution is the throttle controller.
You have to create a discharge curve graph something akin to this one (this one is for Lipo!)
The operating voltage at the load depends on the current being drawn and the rating of the battery!
You’ll notice that the cell voltage drops immediately on the application of load, hovers around some figure between 3.7V and 3.3V for a long time, and then falls like a rock.
For 6S Lipo’s with 25C discharge rate the lower voltage limit would be 3.2 Volt per Cell…
With only 1C discharge rate the lower voltage limit would be 3.6 Volt, after this it falls rapidly…
Two 6S 22000 mAh 25C batteries : 22 x 25 = 550 Amps (the battery pack can provide)
We knew that 2 battery banks are getting too hot (over 60 degree Celsius)
Four 6S 22000 mAh 25C batteries : 44 x 25 = 1100 Amps continuous current…
My guess is your battery pack provides 200 Amps continuous current…
Only the continuous “C” spec matters - forget about the “surge” rating, which is meaningless.
To sum it up, as a general rule, try to always use a battery that can provide twice as much current as the motor can draw. While adhering to this principle, two things will always be a fact: under full motor load, the battery will be strained at only 50%, which means less voltage drop!