It sounds like there might be a faulty battery in the pack. Even though the batteries have been replaced one of them might have a factory defect. The first thing I recommend to do is load test the individual batteries, or bring them into a battery store and have them load tested for you.
If all of the batteries pass the load test, then we can move on to diagnosing the other parts of the scooter.
Please let us know how it goes.
I have not yet tested the battery's but how many amps should the charlys battery charger give out our's gives around 2.3 Amps. Is that enough or do we need to change the charger? Also i tested the scooter with cars battery charger with 24v and it work fine.
Problem with my charly. First here is link to manual i use: https://www.manualslib.com/manual/760758/Mz-Gmbh-Charly.html
Now, when ever i use any power it will show an error on screen (manual page 60) led 5 only on motor runs when i give it power from the out side soure and the fuse are ok. I have change the battery's.
Also when i use the throttle motor does move little, then small click sound, i think its from the control unit and then the error.