Help! Crank sensor

[uncleade]

Hi. Just joined site and have a query. My Freego Hawk has no power to motor and LED unit is not showing battery power symbol yet lights work well and battery shows 41.5 v on volt meter. Took it for repair and technician says crank sensor is broken and unable to supply part (Freego no longer trading). Three questions -
1) is a crank sensor same as a pedal sensor? I have identified a new Freego pedal sensor for sale on ebay.
2) Could a broken crank sensor affect the battery power display on my LED and stop power to motor?
3) If this is the problem, are pedal sensors reasonably easy to fit or is it a specialist technician job?
Would really appreciate answers to above in simple non techi language. Many thanks!

 

[vfr400]

Whatever he says, he hasn't a clue. The LED unit is completely independent. If it doesn't switch on, it's either broken or it has no battery supply. To find the fault, you need a meter. Take the panel off the controller compartment under the battery, pull out the controller and check the voltage on the thick red and black wires with bullet connectors. If you have battery voltage there, have a look at the control panel's connector. Measure between the red and black wires there.

If it turns out that the LED panel is faulty, like a wire pulled off, you can get some basic function (throttle and PAS level 1) by disconnecting the LED control panel and bridging the blue and red wires that come from the controller with a paperclip or similar. If it works like that, see if you can come up with a more robust way of keeping them connected.

To help you understand, the LED panel has three functions all powered by the battery:
1. It's an electronic switch. When you press the power button, it connects the red and blue wires. The blue provides the power for the motor controller. Therefore, the controller will not work if the LED panel doesn't switch on.
2. When you adjust the power level, it sends different voltages down the green wire, which acts as an input signal for the controller. If the controller doesn't see any voltage on that wire, it defaults to level 1. The throttle operation is independent.
3. Battery charge level indicator. It gets this from the red wire, using the black as ground.

The LED panel is powered by the red and black wires at battery voltage. If it's completely blank and doesn't even flash when you press the power button, it's getting no power from the red and black wires, so you have to find out why.

 

[uncleade]

Thanks for that very useful reply and your time. Just to be clear, when I switch power on, the LED panel lights up and the only symbol NOT showing is battery power. Other symbols are showing and I can change level of power ok. No power to motor when I pedal but lights fine.
Just trying to discount the crank/pedal sensor from this problem. Will try the voltage testing on wires round the controller as you suggest. Could this be a faulty LED panel unit?

 

[vfr400]

Before doing anything, you should check the voltage between the blue and black wires when the LCD is switched on. That'll tell you if the controller is getting power. If it is, the motor should work with the throttle even if the pedal sensor is completely bust.

Unless you have money to waste, never start buying new parts until you know where the problem is. It's normally very easy to find the problem by doing some simple measurements with a meter. You have to work your way through eliminating each thing as you go. This first test will determine whether the control panel is the cause. Even though we know it's definitely faulty, we have to figure out what else needs sorting. It could be the battery, motor or controller, or all three (unlikely).

 

[uncleade]

Many thanks for that. Will do some testing when the weather dries up a bit.