The key to getting the most out of your drive system is balance. Here’s what I mean.
You have three basic events in an electric drive: discharge, modulation, and conversion. That is, your batteries discharge the current. The controller and throttle modulate the current going to the motor. The motor converts the current to force. The only secret is that you need to match up what controls these three events, and you get a balanced system.
Here’s a little sheet showing three basic balanced systems- a low, medium and high-power system.
|Typical System Specs|
|Discharge (Battery “C” Rating)||Modualtion (Controller Power Rating)||Conversion (Motor Rating)|
|e-Bike||2C||100 amps||250 watts|
|Scooter||4C||250 amps||500 watts|
|Motorcycle||10C||450 amps||10 KW|
|Race Motorcycle||40C||800 amps||50 KW|
…and here’s an idea of what happens when you have bottlenecks:
|Bottlenecks and Failure|
|Ratings||Too High||Too Low||Just Right|
|Battery discarge||Batteries do not provide all the current they are able to.||Batteries are stressed, possibly damaged by overloading||Batteries remain within operating tolerances for long life, provide maximum safe current|
|Modulation||Controller/circuit is larger, heavier and more expensive than necessary||Contoller becomes bottleneck by not providing available current through to the motor. Overheating and damage to controller or circuit likely.||Controller stays within safe operating ranges and delivers full avaialbe current to the motor.|
|Motor Rating||Motor is too large and heavy for the application||Motor will overheat and fail||Motor runs at about 90% of it’s capacity, stays within safe operating temperatures, and is able to handle the total available current.|