I have an E300 with a control box rated at 30A. My fuse kept tripping at the slightest incline even though I weigh only 150, so I figured I would replace with 25 amp fuse. Now the scooter doesn't work. But if the control box is rated at 30A and a motor only pulls as much amps as it needs, whats broken? I'm thinking the motor, but I'm not sure.
If breaker keeps tripping on the slightest incline that could be caused by a worn out breaker or if the breaker is not worn out then it could point toward a problem with the motor. The motor may have been overheated in the past which caused some of its coil insulation to melt off and allow the coil wires to touch and cause excessive electrical resistance. When this happens sometimes the malfunctioning motor can overload and burn out the speed controller.
To determine which part has failed will require testing.
We could start by unplugging the brake lever's wire connector from the controller and then seeing if the scooter works. If that solves the problem then the brake lever has a faulty switch which is causing the problem.
Next, we would check and see if the power switch light glows when it is on. If the power switch light glows, then the controller is receiving power from the battery pack. If the power light switch does not glow then we would test the Voltage at the connector between the battery pack and controller. There should be Voltage at this connector. If there is no Voltage at this connector then we would inspect the wiring between the connector and batteries, and unplug the battery wires from the breaker and test for continuity between the breaker terminal. The breaker terminals should have continuity when the breaker button is in its pushed in position.
Next, we would disconnect the two red controller wires from the power switch and test continuity of the power switch terminals that the wires are disconnected from. These terminals should have continuity when the power switch is on. If there is no continuity between these terminals when the switch is on then the switch is faulty.
Next, we would test the throttle. The throttle should have continuity between its two brown wires, and between it two orange wires, when it is in the full throttle position. When it is in its zero throttle position there should be no continuity between these wires.
Next, we would test the motor by unplugging it from the controller and applying DC Voltage to its leads. The battery pack could be used as a source of DC Voltage or a spare 12 Volt battery or power supply could be used for this. If the motor runs during this test that only means that it runs and not that it is good because it could still have burned out coil insulation which is causing other problems to occur with the scooter. However, if it runs and all of the previous tests have been performed then that points towards the speed controller not working and needing replacement.
In this particular case where the breaker was tripping on the slightest incline, we recommend replacing both the motor and controller at the same time if testing reveals that either the motor or controller are faulty.
Please let us know how it goes.