Ninebot ESX Error Code 48
"External battery protection board damaged - Please replace battery."
If you clicked the wrong error code, go back to the Error Code Index.
The external battery protection board may actually be damaged, but it is more likely that the battery just got too low.
Leave it on the charger for a while and make sure that the terminals are clean.
Check Ninebot ESX Error Code 42 for examples of how the terminals look when not clean.