Lithium Batteries (LiFePO4)

You've probably heard of lithium batteries catching fire in small devices like phones...Well, the discovery of a safe, nontoxic lithium-ion solar battery chemistry called LFP (technically lithium iron phosphate or LiFePO4) has brought a new standard to the deep cycle lithium battery market. With this safer (and maintenance-free) LFP battery chemistry and high-quality manufacturing from companies like SimpliPhi and Relion, lithium batteries are becoming widely adopted for off-grid energy storage. Yes, they're more expensive, but consider their benefits:

• High energy density - a minimum 2.5x that of lead acid batteries
• Highly efficient so you get out most of what you put in - very little energy is lost as heat
• Outstanding life expectancy - up to 10,000 cycles
• No maintenance or memory problems - there's no need to exercise them (periodic discharging and recharging), so they're great for both full-time and intermittent/infrequent applications
• No additional cost for the sealed format - all LFP batteries are sealed and can be installed in a living space, and in any orientation

Aside from the initial cost, the major disadvantages of lithium solar batteries are the same as other batteries - low performance at freezing temperatures, and damage if operated above maximum or below minimum parameters. SimpliPhi has implemented a real-time equalization circuit - the weaker cells are dynamically cared for so they're not over-stressed. This in combination with the solid-state protection circuit makes for highly reliable and effective off-grid energy storage.

Budget approximately $1.20/Wh for small systems, or as little as $1/Wh for large systems.