A circuit breaker is often only thought of to protect the wiring. In the case of using lifepo4 batteries you may have a significant lower max discharge rate [1C/cell?] than when using something like LiPo 20Ahr batteries which may have a max discharge rate of some 24C/cell. C being the parallel amp capacity of cells.

You would have more ends covered for overload if your circuit breaker capacity is also less than your batt’s max discharge rate.

Some big lifepo4 cells I had were rated a max discharge rate of 40amps. My controller was rated 40 amps so I thought I had max discharge covered without a circuit breaker — not so — every now and then one of the $40/cell would fail. Exceeding max discharge was the type of failing I thought to be case after I added a Cycle Analyst and could see the history of max discharge. The max output of the controller was not a mere 40 amps max — sometimes 50 amps.

Some info on these lifepo4 cells said brief peeks of 50 amps. Damage likely accumulates and will eventually leave a cell with an open circuit. So carry a jumper wire and you can get home under the power of one less cell

From the Web: A common LiFePO4 battery is rated at 100 amp hours and is roughly the size of a group 31 lead acid battery. These batteries are also rated as to their maximum discharge capacity. **100 Amps** max discharge is common.