Illustrative concept image; not a documented customer installation or product recommendation.
A battery can give an SDG&E household two useful benefits: stored electricity for expensive evening hours and power for selected essentials during an outage. Whether the investment fits your San Diego home depends on your tariff, the loads you want to support, and the complete payment proposal. Here is how to compare those pieces.
Can a battery lower an SDG&E bill?
SDG&E’s Solar Billing Plan guide identifies 4 p.m. to 9 p.m. as on-peak hours. Saving daytime solar for that period can reduce higher-priced grid purchases. Existing net-metering customers may have different arrangements; check your bill’s plan name first.
For a concrete rate example, SDG&E’s EV-TOU-5 table effective August 1, 2026 lists a summer on-peak total energy rate of $0.80205 per kWh for bundled service. If a battery delivers 5 kWh that replaces grid purchases at that rate, the avoided energy charge is 5 × $0.80205 = about $4.01.
That is a gross avoided charge. Net savings also account for charging losses, foregone solar export credits, and equipment or PPA costs. The same table lists a standard base services charge of $0.79343 per day—about $23.80 over 30 days—which shifting electricity use does not remove. Discounts, seasons, tariffs, and community choice generation pricing can change the calculation. These rates were checked September 7, 2026; compare the current schedule with your bill.
How long will a battery run my home?
Battery energy capacity is measured in kilowatt-hours (kWh); power output is measured in kilowatts (kW). The Department of Energy’s storage guide explains that distinction. Both matter: enough stored energy does not guarantee enough power to start a large appliance.
For an illustrative runtime calculation, assume an installer estimates 10 kWh available to your selected circuits after reserves and losses, with no solar recharge during the outage:
- At an average 0.5 kW load, 10 ÷ 0.5 gives about 20 hours.
- At an average 2 kW load, 10 ÷ 2 gives about 5 hours.
These are arithmetic examples, not performance promises. Confirm actual usable capacity, starting charge, appliance demand, inverter limits, and the backed-up circuits. A system must be designed and enabled for outage operation. Solar can extend runtime when sunlight and operating conditions allow. Our outage preparedness guide covers essential-load and medical-device planning.
What should an installation quote include?
A useful installed price covers the battery, inverter or compatible controls, backup switching equipment, labor, permits, and any electrical-panel work. Ask whether solar, monitoring, maintenance, and replacement coverage are included. Roof condition, wiring, and the chosen backup scope make a generic online equipment price a poor substitute for an itemized home-specific quote.
Cash, loan, lease, or PPA: what changes?
The CPUC’s Solar Consumer Protection Guide explains the main arrangements:
- Cash purchase: you own the equipment and pay the agreed purchase cost upfront.
- Loan: you own it and repay principal, interest, and applicable fees.
- Lease: the provider owns it and you make scheduled equipment-use payments.
- PPA: the provider owns the solar system and you pay for generated electricity under contract. Confirm the battery is included.
A qualifying solar-plus-battery PPA may require no upfront payment. It still has ongoing costs, and its rate, escalator, term, maintenance, and home-sale provisions matter. See our California solar PPA guide for a fuller explanation.
Compare the whole monthly cost
Here is a hypothetical proposal example, using illustrative inputs rather than a customer quote: 800 kWh of solar generation billed at $0.18 per kWh creates a $144 PPA payment. Add a hypothetical $70 remaining utility bill, including applicable fixed charges, and the combined cost is $214. Compared with a $260 utility-only bill for the same period and household demand, the difference is $46.
Actual production, seasonality, utility prices, export credits, and escalators change those numbers. A PPA generally bills generated energy, not just the portion you use at home. Request a full-year comparison using your electricity history, all payments, and realistic battery dispatch assumptions. Savings are not guaranteed.
Explore your home’s options with West Coast Alternatives, bringing your recent bills and the appliances you want backed up.