Electric Scooter and Electric Bike Basics for the 'Newbie'

Heat - (keep it cool)

Motor Power --Watts---- Brakes---- Batteries ---

•  Heat is the enemy of electric motors and motor controllers.
•  The failure of most electric scooter makers to handle the heat build-up on motor controllers and motors is perhaps the single most limiting factor in electric scooter use.
•  You can’t ride current electric scooter designs like an equivalent powered gas scooter, because the current electric scooters rely on radiation cooling (the motor radiates the heat into the air) with a ‘few’ having some sort of heat sinking enhancement. Only the cheapest of possible gas powered engines rely solely on the passive cooling of the motor by the surrounding air. Most gas power scooters have a built in fan or a fluid reservoir system hat cools the motor.
•  Gas engines have metals/materials that make up the cylinder(s) that can withstand extremely high temperatures and only need to have excess heat transferred away by fluid or air-cooling methods. The electric motor uses electric current and magnetic fields to generate power. The heat that is generated must radiate from the active parts via the motor casing to the surrounding air, unless there are holes in the casing to allow for direct radiation. Most electric scooter motors are ‘sealed’ (no holes) to avoid dirt and water from corroding the inner workings.
•  Electric scooter motors usually are mounted behind the battery box and therefore don’t benefit very much from the air current movement when in motion. Motors that are too hot to touch after a long ride or steep hill climb are probably at risk of early failure, if they are constantly run that way.
•  Motor controllers (often called PWM) pass all of the current that goes to the motor, and therefore are also subject to excessive heat. The controllers are made of electronic components that are a lot less tolerant of excessive heat than the motor. The controller’s power handling components usually radiate excess heat via a ‘heat sink’ that is further enhanced by being attached to the metal casing.
•  A heat sink is usually made out of metals or ceramics that transfer heat rapidly. They are usually shaped in fin configurations for more effective radiation.
•  Operating a motor controller or motor at a higher voltage than it was designed or for a longer duty cycle (on-off) will create excess heat. The controller also might fail if ‘any’ of the electronic components inside are not able to handle the increase voltage.
•  Any sort of air-cooling of either the controller or motor will increase life/reliability, but the motor really needs to be cooled from the inside, to be very effective. Blowing air across the fins of the controller’s heat sink is usually sufficient.
•  The most effective inexpensive way to cool an electric motor is via ‘forced air cooling’.
• You create forced air-cooling of an electric motor by restricting air access to the motor and by providing ample air escape. The restricted air intake has air forced into it via a ‘blower’. The air travels through the internal workings of the motor pushing the hot air as it goes out the ample escape holes on the other side of the motor. Air comes in one side of the motor and is forced out on the other side.
•  A forced cooled motor can often be operated for a duty cycle many times longer than normal, or it often can be run at higher voltages for more power.
•  Most of the warranty issues concerning electric scooters are blown controller or motors. Electric scooter makers could save their profits if they built their scooter with effective cooling. It would be an extremely inexpensive thing to do, considering the alternatives.
•  Traditionally the motor expensive electric scooters makers have used bigger motors and controllers that can handle duty cycles and power needs several times higher than required. But These scooters, however, with their over-kill electric motors and controller may not handle the duty cycle loads of a gas moped costing much less. The consumer must pay through the nose for the couple that can. Scooters like the Numo, Forsen, or eGO2 with forced air cooling probably could compete with gas mopeds in the same price range.

Motor Power --Watts---- Brakes---- Batteries