Adding a battery to your existing solar in Florida

Standard grid-tied solar shuts off when the grid goes down so it can't send power onto lines that crews are repairing. A backup battery fixes that: it disconnects your home from the grid during an outage, so your panels can keep running your home and recharging the battery. When the battery is full, it throttles the solar back. See does solar work in a power outage.

• AC-coupled: the battery has its own inverter and connects on the home's AC side, so your existing solar inverter or microinverters stay in place. This is the usual way to add a battery to an existing system.
• DC-coupled: the panels and battery share one hybrid inverter. It's somewhat more efficient, but on an existing system it usually means replacing the inverter.

• Tesla Powerwall 3: in the U.S., one unit can back up to 7.68 kW AC of existing AC-coupled solar, or 10 kW with expansion units, per Tesla's design guide.
• Enphase IQ Battery 10C: Enphase said in August 2026 that it now works with non-Enphase solar systems up to 15.4 kVA, with 10 kWh usable and 7.08 kW of continuous power, and pairs directly with existing Enphase microinverter systems.
• FranklinWH aPower 2: AC-coupled and marketed for use with Enphase, SolarEdge, SMA and other inverters.
• SolarEdge systems: adding backup typically means upgrading to a SolarEdge Home Hub inverter.

Ask your installer to check your inverter model and system size before quoting. See the best home batteries for Florida.

Your installer has to file with your utility before the battery is turned on. Duke Energy Florida treats a battery added to an existing solar system as a new customer-owned system requiring its own interconnection review, and Tampa Electric has separate battery interconnection forms. FPL's net metering guidelines say battery energy is for your own use and can't be exported to the grid, and batteries without UL 1741 certification must be DC-coupled behind a listed device.

Your solar keeps earning full-retail net metering credits as before. See Florida net metering.

A battery needs a building or electrical permit with plans. Florida's residential building code limits home batteries to 20 kWh per unit, with no more than 40 kWh in utility closets and storage spaces and 80 kWh in garages or on exterior walls. Outdoor units go at least 3 feet from doors and windows into the home. In flood zones, mount the battery and inverter above flood level. See solar batteries in flood zones.

• Enphase IQ6 and IQ7: Enphase lists these systems as compatible with its IQ Batteries, and says full-home backup on them needs at least 10 kWh of battery.
• Enphase M215 and M250: Enphase lists these older microinverters as compatible with IQ Batteries too; other legacy models aren't supported.
• SunPower: in January 2026 SunPower launched a battery program built on the Enphase IQ Battery 10C, with priority for existing SunPower customers, and Enphase says the IQ Battery 10C can pair with other brands' solar.

Daytime-only backup with no battery, Enphase's Sunlight Backup, works only with IQ8 microinverters. Have the installer confirm your exact model numbers before you sign.

It can. Tesla's Powerwall warranty covers units bought from Tesla or a Tesla certified installer and excludes damage from work by anyone else, so use a certified installer for any brand you choose. Tesla also says each existing solar string connected to a Powerwall 3 needs its own rapid shutdown devices (MCIs), which can add equipment to an older system.

Your original installer's workmanship warranty is a separate question. Ask that installer in writing whether a battery added by another company affects it.

EnergySage's 2026 Florida marketplace data runs roughly $850 to $1,040 per kWh of battery in the cities we checked, or about $11,000 to $13,500 for 13 kWh. The 30% federal credit (25D) ended for systems installed after 2025; batteries owned by a leasing company can still use a business credit, so a lease may price lower. Most batteries back up essential circuits; whole-home backup takes more capacity. See home battery cost in Florida.