how to verify external battery on Ninebot ES1?

[mortee]

I attached an external battery to my Ninebot ES1, which initially did indeed give me the extended range and sport mode performance.

However, after some time, it sterted to give me the 42/48 errors, which are presumably the symptom of the utter design failure of the rigidly secured connectors between the battery and the scooter: insecure contacts arising from vibrations.

So, I started to troubleshoot the situation, and tried to check if the control board can detect the external battery, while it doesn't indicate any errors. I've read at several places that the Ninebot app supposedly shows external battery info when one is connected - but I can't find any indication of an extra battery anywhere in the app.

Even if I completely remove the control board, connect it to the motor, internal battery, dashboard and finally the external battery (without the scooter around it), and I verify stable contact on all 4 communication pins between the board and the external battery, using a multimeter.

So, would anyone post a screenshot of what am I supposed to see in the app and where, regarding the external battery?

Thanks.