Hello! We attach great importance to the charging issue you mentioned. The fast charging function requires protocol matching among the charger, data cable, and mobile phone to achieve, and the charger power also needs to meet the data cable requirements (such as 60W or above). We suggest that you use a 60W or higher fast charging head for testing. We have sent a private video of the actual test for your reference. As our main product, this 4-in-1 data cable sells over 100000 units per month, and its overall quality and compatibility have been widely validated in the market. As of now, we have not received any feedback regarding slow charging, so we attach great importance to your situation. We are always responsible for the customer experience and hereby provide you with a "worry free return" service. We have opened an after-sales channel for you through private message and will provide you with a full return and refund service to fully assist you in solving the problem.