What precaution should be taken when connecting a solar panel to a lithium iron phosphate battery?

When connecting a solar panel to a lithium iron phosphate (LiFePO4) battery, it is critical to use a charge controller. Solar panels can output voltages much higher than what the battery can safely handle, which can lead to overcharging, thermal runaway, or permanent damage to the battery cells. A charge controller regulates the voltage and current coming from the solar panels, ensuring the battery is charged safely according to its specific chemical requirements. Distractors like adding a series resistor or simply changing the battery's physical orientation do not safely or effectively regulate the charging profile needed for lithium-based batteries.