Hi, good morning. We are sorry to bring you an imperfect purchasing experience. The customer purchased EVElf304ah. We can guarantee that all batteries we sell are brand new A Grade batteries and come directly from the EVE factory. If customers receive any B-grade or damaged batteries, they can apply for a refund at any time and we will handle it as soon as possible. We will resend the goods or make compensation until the customer is satisfied. Let me return to the customer's question. Lifepo4 batteries will have a voltage difference when they are used for the first time. At this time, we need to balance the batteries one by one. First, you need to use a large current to charge, and then use a small current to continue charging until the battery reaches about 3.6V. This is the battery's ultimate voltage. After a few cycles, all cells are now at the same voltage. Using it at this time can bring out the maximum capacity of the battery.