1) Connecting batteries in parallel can increase the capacity. It means you can run the device longer. It is perfect for the device requiring high capacity.
2) Reduce the risk of system failure. If one battery in the parallel connection fails, the others can continue to power the device.
3) Reduce the risk of overcharged. When batteries are connected in parallel, they all receive the same voltage to avoid overcharging.
(Parallel Example: Connect 12v 100ah lifepo4 batteries in parallel to create a 12V 200ah bank)
(Parallel Example: Connect 2*12v 100ah lifepo4 batteries in parallel to create a 12V 200ah bank)