The most common battery types for photovoltaic storage are lead-acid (flooded and sealed), lithium-ion (including LiFePO4), flow batteries, and sodium-based batteries - each offering unique cost/performance tradeoffs for solar applications. Energy storage batteries (lithium iron phosphate batteries) are at the core of modern battery energy storage systems, enabling the storage and use of electricity anytime, day or night. Sometimes two is better than one. Coupling solar energy and storage technologies is one such case. This energy storage capability transforms your solar installation from a daytime-only power source into a comprehensive energy solution that can provide. Evolving technology is making energy storage more attainable than ever for solar photovoltaic (PV) energy systems, and is useful for a number of reasons.