Make sure the power switch is on

Make sure the key switch or power switch is in the on position.

Check the fuse or circuit breaker

If the scooter uses a fuse, check to see if the fuse is burnt out.

You may need to remove the fuse from the scooter and hold it under a light source to determine if the fuse is burnt out.

For scooters that use a circuit breaker, press or flip the circuit breaker to see if it resets.

Try to push the scooter to start

E-scooters with a single-speed throttle sometimes require a push forward to get going.

Stand on the scooter with one foot and push forward with the other foot while fully depressing the throttle.

Once the scooter reaches walking speed and the throttle is depressed, the scooter will move until you release the throttle or apply the brakes.

Visual, tactile, and olfactory examination

Remove the foot pedal or wiring cover and look for burnt or melted wires, wire connectors, or electrical components.

Also look for loose, disconnected, or damaged wires or wire connectors. Pull and push on all individual wires and wire connectors to make sure they are not loose or disconnected.

Smell the speed controller and motor. Any component that looks burnt or melted, or smells like burnt plastic is almost always defective and should be replaced to prevent damage to the speed controller.

Test other components connected to the speed controller

E-scooter speed controllers are too complex to be easily tested.

Testing other components connected to the speed controller and using a process of elimination is the best way to determine if the speed controller is working properly. If all other components connected to the speed controller test good, then the speed controller is the problem.

Test a fuse or circuit breaker

Sometimes fuses burn out where you can’t see them, and sometimes circuit breakers reset mechanically, but they’re worn out and still don’t work.

Checking the continuity of a fuse or circuit breaker with a multimeter is the best way to determine if they’re working properly.

Test the brake lever switch

The brake lever switch tells the speed controller to shut off the motor when the brake is applied.
Most scooters have a normally open brake switch, but some have a normally closed brake switch.

To test if a normally open brake switch is faulty, disconnect the brake lever wire connector from the speed controller and see if the scooter runs.

If the scooter runs with the brake lever switch disconnected from the speed controller, the brake lever switch is a normally open type and is faulty.

To test if a normally closed brake lever switch is faulty, disconnect the brake lever wire connector from the speed controller and bridge the two terminals in the controller connector with the brake switch unplugged.

If the scooter runs with the controller’s brake switch connector terminals bridged together, the brake switch is a normally closed type and is faulty.

Test the key switch or power switch

Test the key switch or power switch for proper mechanical operation by moving it from the off position to the on position several times. The switch should click into both positions. If the switch feels loose or does not have a noticeable click when switching between the on and off positions, the switch may be defective.

Sometimes a key switch or power switch feels good when switching between the on and off positions and has a positive snap action feel, but it can still be defective. Testing the key switch or power switch for continuity with a multimeter is the best way to determine if it is working properly.

Test the battery charger port

If the battery charger is plugged into the wall, unplug it. Plug the battery charger into the battery charger port on the electric scooter and see if the charger’s indicator light comes on. If the indicator light on the battery charger comes on, then the wiring and wiring connectors to the charger port are good, and the charger port itself is good. Not all battery chargers have an indicator light that comes on when the charger is just plugged into the vehicle, so if the light does not come on, you should do a secondary voltage test with a multimeter as described below.

If you have a multimeter, you can test the voltage at the battery charger port. The voltage level at the charging port should be the same as the voltage level of the battery pack. If the charger port has male terminals, you need to be very careful to avoid shorts between the terminals or in the charger port casing (if it is metal).

Test the battery charger

Make sure there is voltage at the charger port, then test the voltage of the battery or battery pack to confirm it needs charging.

Plug the battery charger into the charger port, plug into the wall, and use a digital multimeter to test the voltage of the battery pack.

If the voltage rises slowly, the charger is charging the battery. Continue charging until the indicator shows a full charge, then test the battery voltage to confirm it has reached 100% charge.

If the charger cannot charge to 100%, there may be a problem.

Test the battery pack

The batteries are load tested by removing the battery pack from the scooter and taking out the individual cells.

The individual battery can then be tested using a car battery load tester.

Most entry level car battery load testers place a 100 amp load on the battery which is too high, so an adjustable carbon stack battery load tester is required and should be adjusted to place a 30 amp load on the battery.

Test battery pack voltage

After reading the voltage, the Battery State of Charge Chart can be used to determine the percentage of state of charge.

A good cell or battery pack will have a voltage at 100% state of charge after it has been discharged and left for a few minutes, or if it has been stored. If the voltage does not rebound to 100% state of charge within a few minutes of the battery pack being discharged, this indicates a faulty or worn cell or battery pack.

When a battery pack has been charged to 100% state of charge and has been left for a period of time and its voltage drops below 100% state of charge, this indicates a faulty or worn battery pack.
Good batteries and battery packs will return to 100% state of charge within a few minutes of the vehicle being driven.

Test the throttle

The on-vehicle throttle test verifies that the controller is providing power to the throttle and that the throttle is sending a signal back to the controller and is the preferred method for testing the throttle.

Check speed controller

Check the speed controller for any burnt or melted wires or wire connectors. If any wires are burnt or melted, the speed controller may be faulty.

Smell the speed controller for any burnt plastic odor. If the speed controller has a burnt odor, it is almost always faulty. If the speed controller has no burnt or melted wires and no burnt plastic odor, it may still be faulty. Test all other components of the electrical system around the speed controller, using the process of elimination to detect if the speed controller is functioning properly.

The speed controller is too complex to be easily tested. Using the process of inspection and elimination is the best way to determine if the speed controller is functioning properly. If all other components of the electrical system test good but the scooter does not run, the speed controller is defective.

Check the motor

Check for burnt or melted wires or wire connections attached to the motor. Burnt or melted wires or wire connections indicate that the motor has overheated and may have caused the plastic insulation to melt from the motor’s electromagnet copper wire windings.

If the insulation on the copper windings melts, they will short out and cause the motor to not run or run slowly. Shorted motor windings can also burn out the speed controller because the speed controller has too much resistance, causing it to overwork and overheat.