Ninebot ESX Error Code 19
"Battery Voltage detection is abnormal, Please check the Battery, Control Board and related connections"
Cause
Often error 19 is caused by a battery that has sat for a while and run out of charge, but then has had it's BMS rebooted by plugging it back in with a charged battery.
Fix
It can be fixed by keeping the battery charging with an external/internal that is partially charged which will allow the charger to keep passing current to the batteries without shutting off.