A couple of problems with this folding eBike I am refurbishing ! It is 24 volts but when I connect my multimeter it the charging port it reads 46 volts ??? The throttle and pedal assist work fine but occasionally after closing the throttle completely the motor will continue to run at a slow speed and is quite powerful and in my opinion dangerous the only way to stop it is by switching off with the key and then switching on again !!! It will then operate quite normally with no problems at all ! Have never come across this problem before and unable to find any answers on this forum or any others ! The other little mystery is the charger, I always check the chargers output and polarity having blown a couple of cheap chargers in the past by not doing this simple check but it’s 24 volt charger does not read anything at all but charges normally !!! Another mystery !
Any help would be appreciated from our knowledgable members.
Your meter is reading the incorrect voltage because its own battery is flat. Replace the battery and try again.
Your motor is continuing to run because your throttle stop is damaged. You can only fix it by replacing it. The throttle has a single ratiometric linear hall sensor in it, typically SS49. Without any magnet close to it and a 5v supply, it will give out 2.5v. With a South magnet adjacent to it, the voltage gets pulled down to 1.0v, and with a North one, the voltage rises to 4.0v. The controller does nothing until it sees something over 1.0v. When the throttle stop gets damaged, it lets the S magnet go past the hall sensor, so without the magnetic field pulling the voltage down to 1.0v the throttle's voltage increases and the controller thinks you've opened the throttle a bit. The stops are only thin plastic, so easily bent or broken. Full width throttles are the worst for that.
Here, you can see what's inside. This one has an iron strip (right hand part) joining the two magnets to get a bit more linearity. The stops can be seen on the left hand part at approximately 2 o'clock and 8 o'clock positions, like little "T"s of plastic. Now you can see how easy to damage they are.
