Glossary
LFP battery (lithium iron phosphate)
An LFP battery (lithium iron phosphate, LiFePO4) is a lithium battery whose chemistry is more thermally stable and withstands more charge and discharge cycles than earlier chemistries (NMC), in exchange for somewhat lower energy density. It is what most current residential solar batteries use and the best option for Florida's heat.
What an LFP battery is
Not all lithium batteries are the same. Phones and many electric cars use NMC (nickel, manganese, cobalt), which stores more energy per pound but tolerates heat poorly and degrades faster with every cycle. LFP uses iron and phosphate: it weighs more for the same capacity, but handles far more cycles, allows deeper discharge without damage, and is much less prone to overheating.
In a home, weight does not matter; lifespan and safety do. That is why the residential industry has moved almost entirely to LFP.
Why it matters in Florida
A battery in a Florida garage runs at high temperatures much of the year, and heat is what shortens the life of any lithium battery the most. LFP chemistry handles that environment better. Even so, placement matters: an exterior wall in the afternoon sun shortens the life of the best battery. Ask the installer to specify the operating temperature range and the location.
The other question is what you want it for. With 1-to-1 net metering, a battery does not increase savings: the grid already does that job. Its role in Florida is backup during outages and hurricanes, and that is a peace-of-mind calculation, not a payback one.
Common mistake
Comparing batteries by kWh of capacity alone. Also look at the chemistry, the warranted cycles, the capacity the warranty promises at the end of the term, and the power (kW) it can deliver at once, which determines how many appliances can start at the same time. We go deeper in how long solar batteries last.
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