We do not recommend simultaneously charging the battery pack while using it to charge other devices. Doing so compromises the battery pack's own charging speed—as the output draws power away from the input—thereby reducing charging efficiency. Furthermore, this practice may cause both the battery pack and the charger to overheat, potentially leading to an interruption in the charging or discharging process. If a user insists on utilizing the device in this manner, they must ensure that at least one battery remains inserted within the charging hub; otherwise, a proper power circuit cannot be established, resulting in abnormal charging behavior. An example illustrating the impact on charging speed: When using a 40W power adapter, if you are solely charging the camera batteries, you can charge four batteries simultaneously. However, if you need to simultaneously charge the batteries *and* use them to charge other external devices, the charging hub will allocate 15W for output purposes, leaving the remaining 25W to charge the camera batteries; in this scenario, you can only charge two batteries at a time.