cespiner said:
Thanks for your response. I have just finished re-checking all the connections, including the solder on the backs of the pins, and everything seems sound. I disconnected and reconnected all the plugs, even gave them a clean, no difference.
At least that's one thing eliminated. It's still possible there's a broken wire somewhere between one connection and another, but you'll need a meter to test for that.
I'm afraid I don't have a voltmeter to test voltages, although at this rate I may need to buy one.
Digital multimeters (DMMs) are pretty cheap; a few dollars. You don't need a "good" one, as it doesn't matter if it's accurate, just close.
A continuity function as well as ohmmeter would be useful for troulbeshooting, but those are common on most DMMs.
What I do know is this: The battery takes charge. Therefore, to my way of thinking, this means the terminal connections to the battery - and from the charge point down - are OK. Otherwise, the charger couldn't charge the battery. Right?
Probably.
And the scooter won't power on even with the charger plugged in. To me, that means that even if the battery or its connections were to blame, the fact that it won't switch on even when power is present at the charge plug means I can discount the battery and its connections.
Possibly.
If the battery's charge and discharge connections are separate (common enough) then the high current discharge connections could still be faulty either at the battery, it's BMS, or between the battery and the controller.
IN that case the charger couldn't power the controller on either, because it's power would still pass thru the battery.
If the charge and discharge connections are the same, then the charger should be able to at least allow it to turn on, with or without the battery connected.
You'd have to trace out the wiring to find that out.
I took the cover off the display and tried the buttons - no obvious signs of any issues with the wiring. I take your point about the possibility of the power switch no longer working, but to be honest it seems extremely unlikely. It's never had any fault, the button hasn't been getting worn or slow to respond. It's completely sudden - one day it powered on immediately with a quick press of the button and the next day, nothing.
That can still be a failed switch or bad connection. Even if it's not visible. Sometimes corrosion can happen inside the switch, where it still works fine, then it corrodes past the point the switch works, and it just doesnt' anymore.
Is it possible a blown controller component could cause the scooter to refuse to power on? Or a short somewhere in the display? I'm thinking my best options may be to order a new controller, or a new display, or even both.
Sure, it could be blown parts. Many controllers with a display use a tiny transistor as a switch to short two wires in the cable from controller to display, that acts as a keyswitch or ignition (KSI).
Once you get a voltmeter, you can measure voltages at the connector between controller and display, which will help you find the KSI wires. There are typically 5 wires in such a connector, with battery positive and ground, two serial data lines (which will measure around 2.5v), and another wire for the KSI that will probably read 0V.
So if you measure voltage across the connector pins on the controller end of taht cable, and you find the same voltage you have across the battery output, then leave the black meter lead on the pin it's on, and move the red meter lead to each other pin in turn. When you find the 0V pin, you can then disconnect the red meter lead from the meter end, and then use it to touch between that 0v pin and the pin the red meter lead read battery voltage on. (you can remove the black lead at that point).
The system should turn on, and be ablet o spin the motor with the throttle (though without the display connected you won't see anything), and it will work, as long as throttle is a separate cable.
If this works, you can then simply cut into the cable, cut the wire that runs to that pin, and cut into the battery positive wire. Add wires from each of those to a new switch, and then you use that switch to turn on the system.
If the throttle cable is part of this cable, then this test also won't work, but another way to test this is to disassemble the display or the controller and find those same wire points, and do the same fix there. In that case the controller to display cable would still be connected, and the test would work if the KSI switch is broken.
It's possible that your display to controller cable isn't wired this way, and in that case the above may not apply.
It's also possible that other parts are blown than the KSI switch, inside the controller or display.
