Ok then ... to summarize.
If my motor is getting all the 24V from the batteries and the speed is 4mph, I can't do anything to gain more speed.
Correct. Only taller gearing. That increases load and so also Amps at all speeds. That needs a bigger motor (lower impedance, greater torque, which needs bigger controller that is higher amp capable. And that all needs bigger cables and larger lower impedance batteries. Ever wondered by there are "bigger" scooters?
Even if I switch to a more powerfull controller (e.g. 24V 1000W)
Unless buying junk on ebay, a scooter or powerchair or EV controller is rated in working volts. And in maximum amp capability. Not watts.
And yes its still just sending the same 24v to the motor. To get more power you need less resistance, a lower impedance motor. That may or may not be higher watts. Watts isnt any help here.
when the motor receive the 24V will keep the same speed because is its "nominal" speed.
All DC permanant magnet motors used in practically everything battery powered have an RPM PER VOLT rating. So my hobby motors may be 900RPM/Volt. So at 2 volts it turns at 900x2=1800rpm. At 6 volts it turns at 900rpm x 6...
That more power only affects to the torque and not to the max speed. It's correct?
What do you mean by power? Power is VOLTS X AMPS = WATTS. Watts is power. You get more power to any DC motor just by loading it more. Or by increasing the voltage at the same RPM/LOAD. You must be specific. If you mean fitting a greater Amp controller like say a 150A mobility controller? No it wont make a blind bit of difference to speed. Only to stall torque and that extra torque tails off as rpm increases. Unless the motor is much lower impedance.
In the other hand, if I make the motor run without load (wheels raised), measure the voltage and there is less than 24V it would be possible that the controller was limiting the voltage.
Max pulsewidth is usually a fraction less than 100% so it will always read a little bit less than battery volts. But not by enough to make any real diference.
It's the only case that maybe putting other main controller would be worth.
Unless its been programmed to less than max speed. Which isnt very often, then you will not gain anything. Other than a lack of proper programming, motor compensation and control. And far less torque.
Because add more batteries to reach 36V and overvoltage the motor with a 36V controller it's not a good idea, isn't it?
Yes it is. Provided you use a PROPER controller that can be configured not to exceed your motors wattage rating for long periods as you hill climb or accelerate. Thats why I did exactly this with my own powerchar. Trust me it isnt simple! Theres no plug and play way to do this.
E.G. In this case I doubled the speed to 16mph, and increased range fron around 15 to 45 miles at the same time. And used 8mph 24V motors.
http://www.wheelchairdriver.com/BM-MK3- ... rchair.htmRegards