The original poster should clearly describe the problem. In Battery City's experience, the sparking problem when charging a 48V lithium battery may be because your charging method is incorrect: connect it to the mains first; , then connect to the battery terminal for charging.
Battery Capital Practical Experience: The maximum voltage of a 48V lithium battery is normally 54.6V. When the battery voltage is higher than 50V, small sparks will be generated at the time of power-up. normal phenomenon and will not cause personal safety; Generally, battery users will consider secondary protection when designing 48V lithium batteries, unless they are copycat or black-hearted battery manufacturers.