View Single Post
Old 09-10-2013, 12:07 PM   #7 (permalink)
zephyrprime
EcoModding Lurker
 
Join Date: Apr 2013
Location: United States
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
What about raising controller voltage output from 48 V to 60V, but limiting current by an additional resistor?
Current is what actually "burns up things", so if I could provide 60V/25A rather than 48V/25A, maybe I could obtain much speed (at obvious cost of less power/torque).

How do I determine the internal resistance of a motor?
If you use a resistor, you will drop current AND voltage. The resistance of all motors is very low and can be measure with a high precision multimeter. You don't want to use a resistor to lower voltage because doing that will waste battery power by turning electricity to heat in the resistor. If you use a resistor to do what you want, the current will also drop so the net effect will be NO INCREASE in range or speed. I've overvolted scooters before so I can tell you that you can probably overvolt by just adding 1 more battery without even using a new controller. Make sure your motor and controller are properly cooled. Sometimes, the manufacturers enclose the motor and controller in the vehicle body thus preventing air flow. You will want to put some holes in the body paneling which face the direction of air flow if this is the case.

Current is NOT what actually "burns up things". It is power. Power = current x voltage. P=IE=IR^2

"at obvious cost of less power/torque" - here you are referring to the trade off between torque and speed. This trade off only happens when power use is kept constant. In your scenario, you are raising power usage by 25%. You will see an increase in both speed and torque if you raise power.
  Reply With Quote