Pairing a battery with your ADU solar system in San Diego County dramatically improves ROI under NEM 3.0. SDG&E customers save more by storing midday solar and discharging during expensive peak hours.
Under NEM 3.0, exporting to the grid pays only $0.05–$0.10/kWh while SDG&E retail rates exceed $0.40/kWh during peak. A battery captures that arbitrage instead of giving it back to the utility.
Adding a single 13.5 kWh battery to your ADU project in San Diego County typically adds $9,000–$13,000 cash. After the 30% federal ITC, effective cost drops to $6,300–$9,100. SGIP rebates may further reduce cost.
No — California Title 24 does not mandate batteries on ADUs in San Diego County. They're optional but increasingly common under NEM 3.0.
Tesla Powerwall 3 leads thanks to its integrated inverter and 13.5 kWh capacity. Enphase IQ Battery 5P is preferred for modular sizing on smaller ADU systems.