First of all, if you mix different LiFePO4 batteries, one of the most obvious consequences is that the effect of your battery pack will not meet your expectations. In the battery pack, high-performance batteries will always be constrained by weaker batteries. For example, when discharging, the voltage is forced to drop to the same level as the weaker battery, which increases the risk of battery damage. In the process of using such a battery pack, the performance difference of each battery will become larger and larger, such as capacity, discharge rate, etc. These differences will cause the BMS to lose its function and fail to provide you with safety protection. Finally, one or more of the batteries will be over-discharged, causing damage or leakage, causing irreparable losses. And due to a problem with the battery pack, the output power is of course unstable, and your electrical appliances may suffer some damages and cause malfunctions.