It is not recommended to use a portable power bank to charge the charging case. Most portable power banks have a current protection function. When the portable power bank detects that the output current is too low, it will disconnect the charging. Due to the small battery capacity and low charging current of the REDMI Buds 6 Lite, which are generally lower than the current protection trigger value of the portable power bank, the current protection function of the portable power bank will be triggered, which can result in insufficient charging.
Note:
If the power bank supports low current mode, it can be used to charge the charging case.