Solar Batteries in Central Florida

This is the battery page. The Cost guide is the solar price. The Duke vs FPL vs OUC note is why the same box is a different product on different streets. If a salesperson leads with “the battery pays for itself on your FPL bill,” stop the meeting.

Two numbers, and why solar dies in an outage

Kilowatt-hour (kWh) is how much energy the box holds. Think of a fuel tank. A common home unit is about 13.5 kWh usable (Tesla Powerwall 3’s published figure). That is the tank.

Kilowatt (kW) is how hard it can push at once. Think of the size of the pump. A Powerwall 3 is rated about 11.5 kW continuous. An Enphase IQ Battery 5P is about 5 kWh and 3.84 kW per cabinet, so you stack them. Starting a central air conditioner needs a short surge. Runtime is kWh. Whether the compressor even starts is kW.

A normal grid-tied solar system turns off when the grid turns off. That is not a defect. Inverters follow a safety rule (UL 1741 and utility interconnection) so they do not feed a dead line and shock a lineman. Panels on the roof do nothing for the fridge until you add a battery (or a generator) and a transfer setup that isolates the house. “I have solar, so I have power in a storm” is false unless the quote named backup gear.

What it costs in 2026

Plan on about $10,000 to $16,000 installed for one home battery in the 10 to 14 kWh class, before a main-panel upgrade. EnergySage’s Florida storage average in September 2026 was about $12,100 for 13 kWh (about $930 per kWh). A second unit for longer backup is not twice the labor, but it is close to twice the hardware.

That price should include the battery, the gateway or automatic transfer switch (the box that disconnects you from the dead grid and feeds selected circuits), permit, and commissioning. Ask what is not included: a new breaker panel, a critical-load subpanel, extra conduit, a concrete pad, or moving the unit out of the sun.

There is no 30% federal Residential Clean Energy Credit (tax code section 25D) on a battery you own if installation finished after December 31, 2025. Quotes that still subtract it are last year’s law. A lease company may still use a commercial credit on their side. That is their tax file, not yours. See the Incentives guide.

Florida’s 6% state sales tax should be off storage that is part of a solar energy system (Florida Statute 212.08(7)(hh)). A battery with no solar at all can be a gray area. Confirm the tax line is $0 before you sign. Florida Statute 193.624 also keeps the value of a qualifying storage device off your property-tax assessment. Check the next TRIM notice anyway.

Duke and FPL: buy it for the storm, not the bill

Duke Energy Florida and FPL still bank extra solar kWh at the retail energy rate inside the calendar year (Florida Administrative Code 25-6.065). Daytime power you cannot use becomes a credit on tonight’s air conditioning, on paper, without a battery. Round-trip losses in a battery (you put in 10 kWh, you often get about 9 kWh back) make cycling for the bill a weak deal when the utility already moves that kWh for you at 1-for-1.

What the battery does on those streets:

• Keeps selected circuits on when the neighborhood is dark.
• Lets the solar array keep making power during an outage (instead of sitting idle) so the tank can refill on a sunny day after the storm.
• Does not erase FPL’s $30 minimum base bill or Duke Energy Florida’s $14.35 customer charge.

Neither utility is running a general home-battery rebate in 2026 that changes this math. If a quote invents one, ask for the program page.

OUC: the one place a battery can also be a bill tool

On new OUC service, extra power you send out after October 31, 2026 is credited at the community-solar energy rate (OUC has quoted about 4.6 cents), then later the fuel rate (about 3.8 cents). Power you use in the house still avoids the full retail price (about 10.7 cents on the old full-retail export figure). Holding afternoon kWh for evening air conditioning captures the spread. Exporting it does not.

OUC will pay $150 per kWh of nameplate storage, up to 50% of battery-plus-install cost, capped at $2,000 per premise. The battery must be paired with an interconnected array. Taking the rebate means you forfeit TruNet full-retail export and sit on the cheaper export schedule.

For a brand-new OUC array after the grace, that trade is often aligned: export is already cheap. For a grandfathered account that still gets retail export through 2045, $2,000 can be a bad sale of many years of retail credits. Run the exports before you click apply. Details: Incentives guide and the Duke vs FPL vs OUC note.

What one battery actually runs in Florida heat

A typical 3-ton central air conditioner draws about 2,400 to 3,500 watts while running, and much more for a second or two at start. At 3 kW, a 13.5 kWh tank is about 4 hours of continuous cooling, more if the unit cycles, less if the house is a sieve and it is 95°F after the storm.

Essential loads without central air (fridge, some lights, router, phones, a few outlets) often use about 4 to 6 kWh per day. The same 13.5 kWh tank is then on the order of two days, longer if you are careful, shorter if someone leaves the oven on.

Whole-home backup that includes central air through a multi-day outage is two or three batteries and a solar array that can refill them on a clear day. Cloudy storm days refill little. That is why a battery is not a week-long generator substitute unless you size it like one and you have sun.

What you want on	Rough storage	What to expect
Fridge, lights, internet, phones	One 10-14 kWh unit	About 1-2 days, then you need sun or the grid
Those plus a window unit or mini-split	One strong unit, or two smaller ones	Hours of cooling, not all night every night
Central air plus the whole panel	Two or three units, and enough solar to recharge	Possible on a sunny recovery day; expensive; still not unlimited

Ask which job you are buying:

• Critical-load panel: selected circuits only. Cheaper. Most honest for one battery.
• Whole-home: the main panel, with the battery and inverter able to start the big loads. Costs more. Still limited by the tank.

A battery sold as “whole home” that cannot start the air conditioner is a lighting product with a fancy name. Check continuous kW and the startup surge rating against your outdoor unit’s nameplate.

Chemistry and Florida heat

Most new home units in 2026 use lithium iron phosphate (LFP), including Powerwall 3 and Enphase IQ Battery 5P. Older packs sometimes used nickel-manganese-cobalt (NMC). LFP is the better fit here: more stable in heat, no cobalt, and usually more cycles. It is still a battery. Heat still ages it.

Do not mount the cabinet on a west wall in full afternoon sun if you have a shaded north wall or a garage that is not an oven. Datasheets often allow outdoor install up to about 122°F ambient. A black box in August sun is hotter than the airport reading. Shade, airflow, and a little distance off a hot wall matter more than the marketing word “outdoor rated.”

This is the same climate story as panels: Florida’s problem is wet heat and long summers, not a magic cell type. See the heat note on this site.

Adding a battery to solar you already have

A new solar-plus-battery job can share one hybrid inverter (Powerwall 3 has solar inputs built in). Adding a battery later to an existing array is usually AC-coupled: the old solar inverter stays, and the battery has its own inverter and talks to the house on the alternating-current side. It works. It can cost more per kWh than doing both at once, and the installer has to prove the solar will still run in an outage (some pairs do this well, some need extra boxes).

If your current company is gone, you still own the panels. A new licensed electrical or solar contractor can add storage. Bring the original one-line diagram, inverter model, and interconnection paperwork. Duke Energy Florida, FPL, and OUC will want an updated interconnection if you change how the system sits on the grid. Do not let anyone tie a battery in without a permit.

A battery does not increase FPL’s 115% yearly production cap by itself. It can change when you use power. On new OUC, using stored kWh in the evening is the point of the box.

Battery vs generator

A standby generator (propane or natural gas) can run central air for days if you have fuel. Installed cost for a whole-house unit is often in the same neighborhood as one or two batteries, sometimes less. It makes noise, needs maintenance, and you must store or pipe fuel. After a wide storm, gasoline is a fight. Propane on site is better if the tank is full.

A battery is silent, automatic, and pairs with solar so a sunny day refills it. It does not last a week of rain and 95°F on one 13.5 kWh box. Many houses end up with a small generator as backup-to-the-backup, or they pick one product and accept its limits. Mixing both is a design, not a default quote.

If you already have a generator interlock, tell the solar company before they design the gateway. Two isolation schemes on one panel is how people get expensive change orders.

How to read a battery quote

1. Usable kWh, continuous kW, and chemistry, from the datasheet, not “whole home” on a flyer.
2. Which circuits stay on. A list, not a vibe.
3. Gateway / transfer switch included, and whether the main panel must be replaced.
4. Will the solar still make power in an outage? If no, you bought a tank that cannot refill from the roof.
5. Round-trip efficiency (often about 90% on AC-coupled systems). You will not get every solar kWh back out.
6. Warranty in years and remaining capacity (common: 10 years to about 70% for Tesla-class; Enphase 5P publishes 15 years / 6,000 cycles to a lower remaining-capacity floor). Who climbs the wall if the installer is gone.
7. Florida license on the contract (Certified Solar Contractor or Certified Electrical Contractor). Same rules as the installer guide.
8. Utility named. OUC rebate terms in writing if you will apply, including the export you give up.
9. Tax line $0 on qualifying solar-plus-storage equipment. No fake 30% federal credit.
10. Location: shade, not a west-facing oven.

Add a battery when you want lights and the fridge through a Central Florida outage, or when you are on new OUC service and you will actually use the stored kWh in the house. Do not add one because a 2025 brochure said it “completes the system.” A well-sized solar array on Duke Energy Florida or FPL is already a bill machine. The battery is the storm machine, unless your utility has made daytime export cheap.