EWT Factory Support IFR26650 4S 12AH 12V Lifepo4 Battery Pack

1. Lithium battery buck-boost test

First of all, let the lithium battery be lowered to 3.3V through the step-down chip, and then power the microcontroller and Bluetooth module, and then plan to rise to 7V to bring a load.

Result: The Bluetooth module does not work and cannot be searched. Remove Bluetooth, the microcontroller and the load are working normally. When the microcontroller is removed, the Bluetooth works normally with the load. When a step-down is not used, all three work normally when a separate set of power supplies is given.

Note: XC6206 for buck and FD6291 for step-up.

2. Lithium battery step-up and step-down issues

The single voltage of lithium-ion batteries has a certain range, for example, the normal working voltage range of lithium iron phosphate batteries is 2.5V-3.65V, and the normal working voltage range of lithium manganese oxide and ternary batteries is 3V-4.2V.

Lithium-ion batteries require battery protection boards when the total voltage is 60V and below. For 60V or more, a battery management system (BMS) is required. The role of these two devices is to protect the battery for normal operation.

Note that after the number of strings in the battery pack is set, the battery pack voltage cannot be adjusted arbitrarily. That is, the voltage change of the battery pack can only change within the normal operating voltage range: when charging, it rises from the lower voltage limit to the upper voltage limit. When using electricity, it drops from the upper voltage limit to the lower voltage limit.

Understand this problem, if you want the lithium battery to have a large range of buck-boost voltage, you can adjust it at will.