Here is the only way to finally solve ES2/ES4 external battery connector issues once and for all. : r/ninebot
Ninebot es2/ES4 external battery connector burned off and does not come off. Any ideas how to remove it, so I can replace it with the new one ? : r/ElectricScooters
How to replace battery pack for Ninebot Segway Max G30 electric scooter? - YouTube
First time opening a Ninebot ES4 external battery. | Segway Ninebot ES4 external battery disassembled. | By Perth Electric Scooter Repairs | G'day everyone this is Nick from Perth Electric Scooter Repairs.
How to Repair a Ninebot Max E-Scooter Easily?Useful Tips to Service Ninebot! - WalkSmart Australia
How to Install/Replace the External Battery on Ninebot ES1/ES2/ES4, E22, E25 and E45 Scooters - YouTube