Why pair a battery with solar
A standalone solar system stops producing the moment PSEG sees a fault on the line — federal safety rule. That's exactly when you want power most. Adding a battery (Tesla Powerwall, Enphase IQ Battery, FranklinWH) lets the system island itself: your essential circuits keep running on battery + sun, and the system re-syncs with the grid automatically when PSEG comes back.
Beyond outage backup, batteries shift solar production from midday (when you're typically not home) to evening peak (when LIPA rates are highest and you actually use lights / TV / AC). Two real savings on the same hardware.
Tesla Powerwall vs Enphase IQ Battery
Tesla Powerwall 3 — 13.5 kWh usable per unit, integrated inverter, AC-coupled or DC-coupled mode, 10-year warranty. Best for whole-home backup ambitions and homeowners already invested in Tesla ecosystem. Industry-standard sleek aesthetic, single-unit footprint about a fridge.
Enphase IQ Battery 10C / 5P — modular 5 kWh units stacked to whatever size you need (10/15/20/25 kWh common). Microinverter architecture means single-panel-level monitoring + no single point of failure. Best for homeowners who want granular monitoring, modular expansion, or already have Enphase microinverters on the solar side.
FranklinWH aPower 2 — 15 kWh usable, lithium iron phosphate (safer chemistry), 12-year warranty. Newer to LI but rapidly adopted for the longer warranty and the LFP chemistry.
NY State battery incentives
The federal residential credit that used to cover a purchased battery ended on December 31, 2025, so a 13.5 kWh Powerwall bought in 2026 costs about what it is quoted at — roughly $14,500 installed. NYSERDA has offered a residential battery incentive paid per kWh of storage; funding is limited and changes, so we confirm what is open at quote time instead of assuming it.
PSEG's Long Island demand-response rebate provides additional credits if you enroll the battery in their grid-service program — they're allowed to discharge a portion during peak system events, you keep most of the capacity for your own use.