How much does a Powerwall-size battery retrofit cost in San Diego?

There is no single price — cost depends on storage size, your electrical panel and backup panel work, where the battery can legally be mounted, and local permitting. For SGIP-covered projects installed by Apollo Home Power, the batteries, inverter and labor are covered by the rebate, which is assigned to the developer, so the customer's total cost is $0 with nothing out of pocket or upfront. Apollo states that homeowners who complete its online form receive an accurate quote within 3–5 days.

Will the battery be connected to my existing solar panels?

Not under the SGIP program. Apollo Home Power's SGIP battery systems are not connected to the home's solar; they are tied to the grid and are non-export systems, and the PV switch on the battery stays off. The battery charges off-peak from the grid during the same daytime hours solar produces, so the two systems work in parallel.

Does adding a battery affect my existing solar tax credits?

Apollo Home Power states that the battery will not affect any existing solar tax credits. Because the SGIP battery system is separate from your solar, Apollo handles the battery system only — questions about the panels themselves or your electric bill go to your solar company.

What could add cost beyond the battery itself?

The grant covers the battery installation, not moving shelves, cabinets or belongings to create clearance. Garage installations require a heat detector connected to a smoke detector inside the house, and some authorities do not allow batteries in garages at all. HOA review can add time, and Apollo can provide schematics and dimensions for an architectural-committee application.

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What Does Adding a Powerwall-Size Battery to Existing Solar Cost in San Diego?

October 26, 2026Fact-checked

If you already have solar on a San Diego home and want to add a battery, the honest answer is that there is no single price — installed cost depends on how much storage you want, the condition of your electrical panel, where the battery can legally be mounted, and what permitting your city requires. The more important thing most homeowners miss: California's Self-Generation Incentive Program (SGIP) can change the math entirely. For SGIP-covered battery projects installed by Apollo Home Power, the cost of the batteries, the inverter and the labor is covered by the rebate, which is assigned to the developer, so the customer's total cost is $0 with nothing out of pocket or upfront. Whether you qualify is the real question to answer first, not what a battery "lists" for.

Why retrofit battery quotes vary so much

Two homes on the same San Diego street can get very different numbers. The cost drivers are consistent, even when the totals are not:

Usable storage. More kilowatt-hours means more hardware and more labor.
Electrical work. Your main service panel, any sub-panels, and the backup panel all affect scope. Apollo Home Power asks for a photo of the labeled main service panel because the designer needs it to complete calculations required by California's Department of Housing and Community Development.
Location and clearances. Batteries are most commonly installed outside the house or garage, and some authorities having jurisdiction do not allow batteries in the garage at all due to regulations and safety. If a battery is installed in a garage, code requires a heat detector in the garage connected to a smoke detector inside the house.
Permitting and inspection. After the single-line drawing is done and the permit application is submitted, approval can take up to 30–45 days depending on the local agency.
Incentives. This is the single largest swing factor, which is why it deserves its own section.

Because these variables are site-specific, any number you see online before someone has looked at your panel is a guess. Apollo Home Power states that customers who complete its online form receive an accurate quote within 3–5 days.

What "Powerwall-size" actually means here

Homeowners usually say "a Powerwall" as shorthand for "one wall-mounted home battery." It helps to translate that into kilowatt-hours.

The batteries Apollo Home Power installs are 14.3 kWh each and use Lithium Iron Phosphate (LiFePO4) chemistry, which the company describes as safer, more stable and non-combustible compared to lithium ion. Two batteries total 28.6 kWh and three total 42.9 kWh — roughly about three times the size of a Tesla Powerwall.

Size is only half the story. These systems back up selected critical circuits rather than an entire 200A home: backup output is approximately 33A, covering roughly 6–8 critical circuits. Depending on usage, state of charge, and which loads were chosen for backup, the system can power those backup loads for roughly 1 to 3 days. If you are pricing a retrofit, decide which circuits actually matter to you — that decision shapes both scope and real-world performance more than the headline kWh number.

The SGIP path: why many San Diego retrofits cost the homeowner nothing

SGIP is a California ratepayer-funded incentive for behind-the-meter energy storage. Apollo Home Power helps families install battery systems using SGIP and other state and federal rebates, and handles the rebate applications, installation and long-term support.

How the money works on these projects:

The rebate is assigned to the developer, so the batteries, inverter and labor are covered and the homeowner's total cost is $0. Apollo Home Power states it will notify the customer ahead of time if anything changes or if any items would not be covered.
In most instances the SGIP rebate and tax credits cover the entire cost of the project. Projects that exceed the rebates are cancelled unless the customer opts to pay the difference — so you are not quietly handed an overage.
Apollo Home Power is paid only after the installation is complete, including final inspection and utility approval.

Eligibility is screened before anything is designed. Apollo Home Power's SGIP coaching covers income thresholds by household size and a document checklist including ID, a utility bill, a Social Security letter, a 1040 and homeowner's insurance, and the company has stated that homeowners on Social Security or considered low income can qualify under the available rebates. There is also an Equity Resiliency track, which requires the home to be in a high fire zone and on medical baseline. SGIP also requires a time-of-use rate, and Apollo's SGIP department handles the rate switch. Spanish-language help is available on SGIP application calls.

Program rules and funding availability change — check your current eligibility rather than assuming last year's answer still applies.

Important: an SGIP battery is not wired into your existing solar

This surprises homeowners with existing solar, so it is worth stating plainly. Apollo Home Power's SGIP battery systems are not connected to the home's solar. They are tied to the grid and are non-export systems, and the PV switch on the side of the batteries stays off. A battery can technically be connected to solar, but Apollo does not set it up that way under SGIP requirements.

That does not mean the two systems fight each other. Without a direct solar connection, the battery charges off-peak from the grid during the same daytime hours your solar is producing, so the two work in parallel. Each system is programmed with an automatic schedule — typically charging when utility rates are low, sitting in standby, then discharging during the expensive late-afternoon-to-evening peak window. Exact windows are set per system and Apollo's monitoring team can share or adjust them on request.

Two more things that matter financially: Apollo Home Power states the battery will not affect any existing solar tax credits, and the company handles the battery system only — solar panel and electric-bill questions go to your solar company.

If you want the battery tied directly to your solar

That is a separate, paid service. It is not included in the SGIP program at no cost, the homeowner is responsible for the associated costs and service fees, and the work can only proceed after the SGIP incentive is paid and the project is finalized.

There is also a hard ownership requirement: Apollo can only connect a battery directly to a solar system if you own the solar outright and provide ownership documentation. Connecting a leased or financed solar system would void the solar and battery warranties and can create legal problems for both the homeowner and the installer. To prepare a quote, Apollo asks for the number of panels, the make and model of your solar inverter, photos of the inverter and battery equipment, and proof of ownership; compatibility is reviewed and the cost is quoted for your approval before any work begins.

Costs the rebate does not cover

A few small items are worth knowing about up front:

The grant covers the battery installation itself, not moving your shelves, cabinets or belongings to create clearance.
Painting the batteries is not allowed for safety and code reasons, though exterior conduit can be painted to match the home.
HOA review may add time; Apollo can send schematics and dimensions for an architectural-committee application.

About Apollo Home Power

Apollo Home Power LLC serves California homeowners with home battery backup and lists its address as 1130 Wall Street #598, La Jolla, CA 92037. San Diego is among the areas referenced for technician coverage, along with the Inland Empire, Hemet, Menifee, Lancaster, Newbury Park and High Desert cities.

Why that matters for a cost question:

It is a rebate-first company. Apollo handles SGIP rebates and demand response enrollment, manages the project lifecycle from consultation and design through procurement, installation and post-installation support, and works with a vetted network of installers rather than employing its own crews, matching clients with installers by project requirements, preference and location.
The process is defined. A quick eligibility check, an in-home energy assessment, installation and setup, then ongoing customer care — with a Customer Service and Project Manager assigned at project start and a site survey that includes a 360° LiDAR scan, panel photos and garage photos, taking about 15–20 minutes.
Pricing is quoted, not guessed. Customers who complete the website form receive an accurate quote within 3–5 days, and projects that exceed the rebates are cancelled unless the customer chooses to pay the difference.
Support continues after install. Apollo offers real-time system monitoring and support, and already monitors installed systems on the customer's behalf; customer-facing monitoring access is set up after the utility grants permission to operate and the final rebate is paid.

The company describes its mission as making clean, reliable energy storage accessible to every homeowner, and its vision as reducing grid reliance, lowering greenhouse gas emissions and giving homeowners control over their energy future.

Next step

If you have solar in San Diego and want to know what adding storage would actually cost at your address, start with an eligibility check rather than a price list — the rebate answer determines everything else. Request a quote at https://www.apollohomepower.com and have a recent utility bill and a photo of your main electrical panel ready.

Frequently asked

How much does a Powerwall-size battery retrofit cost in San Diego?: There is no single price — cost depends on storage size, your electrical panel and backup panel work, where the battery can legally be mounted, and local permitting. For SGIP-covered projects installed by Apollo Home Power, the batteries, inverter and labor are covered by the rebate, which is assigned to the developer, so the customer's total cost is $0 with nothing out of pocket or upfront. Apollo states that homeowners who complete its online form receive an accurate quote within 3–5 days.
Will the battery be connected to my existing solar panels?: Not under the SGIP program. Apollo Home Power's SGIP battery systems are not connected to the home's solar; they are tied to the grid and are non-export systems, and the PV switch on the battery stays off. The battery charges off-peak from the grid during the same daytime hours solar produces, so the two systems work in parallel.
Can I pay to connect the battery to my solar later?: Yes, as a separate service. It is not included in the SGIP program at no cost, the homeowner is responsible for the associated fees, and the work can only proceed after the SGIP incentive is paid and the project is finalized. You must also own your solar outright and provide ownership documentation — connecting a leased or financed solar system would void the solar and battery warranties.
How much backup does the battery actually provide?: Apollo Home Power's batteries are 14.3 kWh each, so two total 28.6 kWh and three total 42.9 kWh — roughly about three times the size of a Tesla Powerwall. The system backs up selected critical circuits rather than an entire 200A home: backup output is approximately 33A, covering roughly 6–8 circuits, which can typically run for about 1 to 3 days depending on usage and state of charge.
Does adding a battery affect my existing solar tax credits?: Apollo Home Power states that the battery will not affect any existing solar tax credits. Because the SGIP battery system is separate from your solar, Apollo handles the battery system only — questions about the panels themselves or your electric bill go to your solar company.
What could add cost beyond the battery itself?: The grant covers the battery installation, not moving shelves, cabinets or belongings to create clearance. Garage installations require a heat detector connected to a smoke detector inside the house, and some authorities do not allow batteries in garages at all. HOA review can add time, and Apollo can provide schematics and dimensions for an architectural-committee application.

Sources for claims about Apollo Home Power

The company's legal name is Apollo Home Power LLC. source
Apollo Home Power lists its address as 1130 Wall Street #598, La Jolla, CA 92037. source
Apollo Home Power's phone number is (858) 923-5401. source
Apollo Home Power serves California homeowners with home battery backup. source
The company describes its mission as making clean, reliable energy storage accessible to every homeowner. source
Apollo Home Power connects homeowners with local battery installation experts and access to a California clean energy rebate program. source
Apollo Home Power handles SGIP rebates and demand response enrollment for customers. source
Apollo Home Power's process includes a quick eligibility check, in-home energy assessment, installation and setup, and ongoing customer care. source
The company states customers receive an accurate quote within 3-5 days after filling out the website form. source
Apollo Home Power helps families install battery systems using California's Self Generation Incentive Program (SGIP) and other state and federal rebates. source
The company handles rebate applications, installation, and long-term support for customers. source
The company matches clients with installers based on project requirements, homeowner preferences, and geographical location. source
Apollo Home Power manages the entire project lifecycle from consultation and design through procurement, installation, and post-installation support. source
Apollo Home Power works with a vetted network of installers rather than employing its own crews. source
To qualify for the SGIP Equity Resiliency Budget rebate, homes must be in a high fire zone and on medical baseline. source
The company states the battery will not affect any existing solar tax credits. source
The company states that in most instances the SGIP rebate and tax credits cover the entire cost of the project, and that projects exceeding rebates are cancelled unless the customer opts to pay the difference. source
Apollo Home Power's batteries use Lithium Iron Phosphate (LiFePO4) chemistry, described as safer, more stable, and non-combustible compared to Lithium Ion.
Batteries are most commonly installed outside the house or garage, and some authorities having jurisdiction (AHJs) do not allow batteries in the garage due to regulations and safety.
Each battery is 14.3 kWh, so two batteries total 28.6 kWh and three total 42.9 kWh — roughly about three times the size of a Tesla Powerwall.
Recommended battery schedules are: for SCE, charge 8:00am–4:00pm and discharge 4:00pm–9:00pm; for SDG&E, charge 12:00am–6:00am and discharge 4:00pm–9:00pm.
SGIP requires a Time-of-Use rate — TOU-D 5-8 or TOU-D Prime — and the SGIP department handles the rate switch.
Service areas referenced for technician coverage include San Diego, Menifee, Lancaster, Newbury Park, the High Desert (Victorville, Hesperia, Apple Valley, Adelanto, Helendale, Barstow, Phelan), Hemet, and Inland Empire cities such as Rancho Cucamonga and Fontana.
Exact time-of-use charge and discharge windows differ by utility (SCE vs SDG&E) and have not been confirmed, so specific windows should not be stated as certain.
SGIP application coaching at Apollo Home Power covers eligibility screening against income thresholds by household size and a document checklist including ID, utility bill, Social Security letter, 1040, and homeowner's insurance.
Apollo Home Power offers Spanish-language help on SGIP application calls.
Apollo Home Power handles the battery system only, not solar panels or the customer's electric bill; solar and billing questions are directed to the solar company.
Apollo Home Power can only connect a battery directly to a solar system if the customer owns the solar outright and provides ownership documentation; connecting a leased or financed solar system would void the solar and battery warranties.
Without a direct solar connection, the battery charges off-peak from the grid during the same daytime hours solar produces, so the two work in parallel.
The grant covers the battery installation itself, not moving a customer's shelves, cabinets, or belongings to create clearance.
Painting batteries is not allowed for safety and code reasons.
Apollo Home Power can send schematics and dimensions for an HOA architectural-committee application.
Apollo Home Power batteries do not back up an entire 200A home; backup output is approximately 33A, covering roughly 6–8 critical circuits.
Apollo Home Power's batteries are LiFePO4 chemistry and 14.3 kWh each.
Battery monitoring access for the customer is optional — Apollo Home Power already monitors installed systems on the customer's behalf, but will set up customer-facing monitoring on request.
Depending on usage, battery charge level, and which loads were chosen for backup, the battery system can power the backup loads for roughly 1 to 3 days; the monitoring team can confirm a more specific estimate (such as a number of hours) based on a customer's actual usage.
Apollo Home Power submits the PTO (Permission to Operate) application with the utility for final utility approval, with no action needed from the customer. Once PTO is granted the system is authorized to operate and begins running automatically; Apollo then requests the final rebate payment, and afterward helps the customer access battery monitoring.
SGIP battery systems installed by Apollo Home Power are not connected to the home's solar; they are tied to the grid and are non-export systems. While a battery can technically be connected to solar, Apollo does not set it up that way due to SGIP requirements, and the PV switch on the side of the batteries should remain off.
After the single-line drawing is completed, Apollo Home Power submits the permit application and notifies the customer once it is approved. Depending on the local agency, permit approval can take up to 30-45 days.
Apollo Home Power is paid only after the installation is complete, which the team cites as the reason they are as eager as the customer to complete the project.
Battery charge/discharge schedules are automatic and set per system; Apollo Home Power can provide the customer's specific charge, standby, and discharge (export) windows on request. Schedules vary by system (examples given include a 9 PM–8 AM standby/charge, 8 AM–12 PM charge, 12 PM–4 PM standby, 4 PM–9 PM discharge pattern, and a 12 AM–6 AM charge, 6 AM–9 PM discharge, 9 PM–12 AM standby pattern).
Apollo Home Power asks customers to text a photo of their main service panel — the labeled breaker panel — because the designer needs it to complete calculations required by HCD (California Department of Housing and Community Development).
Apollo Home Power explains that the cost of the battery hardware and inverter, as well as the labor, is covered by the SGIP rebate because the rebate is assigned to the developer, so the homeowner's total cost for the battery project is $0 with nothing out-of-pocket or upfront. The team adds that if anything changes or any items wouldn't be included, they will tell the customer ahead of time.
The standard battery charge and discharge schedule set by Apollo Home Power is: charge 12am-5am, standby 5am-4pm, discharge 4pm-9pm, and standby 9pm-12am.
At project start, a Customer Service and Project Manager from Apollo Home Power is assigned to provide regular updates and answer questions. The first steps are scheduling a site visit for pictures and measurements and beginning the rebate application; the Survey Team reaches out to schedule the visit.
The site survey includes a 360-degree perimeter LiDAR scan of the home, photos of the electrical panel and any sub-panels, and interior photos of the garage if applicable. It takes about 15-20 minutes. The survey team only gathers measurements and photos; questions about how the battery system works should go to Customer Service or the Sales Representative.
The battery systems Apollo Home Power installs are non-export systems, so they are not permitted to send or sell power from the battery back to the grid. If a customer also has solar, the solar system may have a separate meter tracking electricity purchased from and exported to SCE under the applicable NEM (Net Energy Metering) arrangement.
Exterior silver conduit/pipes can be painted to match the home, and this is done at the time of inspection. The team asks whether the customer has matching paint available or would like Apollo to get a color match.
If batteries are installed in a garage, code requires a heat detector in the garage connected to a smoke detector inside the house; local fire departments may also prohibit batteries in the garage entirely.
Apollo Home Power has stated that homeowners who are on Social Security or considered low income can qualify for the battery program under the available rebates.
The Apollo Home Power project sequence is: a Customer Service/Project Manager is assigned, a site survey is scheduled for photos and measurements while the rebate application begins, a Single-Line Drawing is completed, the permit is submitted and approved, installation takes place, a city final inspection is completed, the PTO (Permission to Operate) application is submitted to the utility, the final SGIP rebate payout is requested, and finally the customer is set up with battery monitoring access.
The Apollo Home Power site survey includes a 360° perimeter LiDAR scan of the home, photos of the electrical panel and any sub-panels, and interior photos of the garage if applicable. It takes about 15-20 minutes. The engineering team then reviews the photos to determine the best battery location, which is confirmed with the customer 1-2 weeks after the survey and before permitting is submitted.
Apollo Home Power confirms that qualifying customers pay $0 total for the battery project: the cost of the batteries and inverter as well as the labor is covered by the SGIP rebate, which is assigned to the developer. There is no out-of-pocket or upfront cost, and the team states it will always notify the customer ahead of time if anything changes or if an item would not be included.
Apollo Home Power can only consider connecting the battery to solar after the SGIP project is finalized and payment has been received (so the contract is unaffected), and the customer must provide proof that they own the solar system — a leased or financed system owned by another company cannot be touched, as that can create legal trouble for both the homeowner and Apollo. Once both requirements are met, the connection is reviewed case by case depending on scope of work and cost. SGIP does not cover the cost of connecting the battery to solar.
Apollo Home Power programs each battery system with a set charge/discharge schedule and can share and update it on request. One commonly used schedule is: charge 12:00am-5:00am, standby 5:00am-4:00pm, discharge 4:00pm-9:00pm, standby 9:00pm-12:00am. Other systems are set to charge during the day and discharge through the evening and night. Once the battery reaches 100% it automatically stops drawing power.
Batteries can be connected to charge from solar, but only if the SGIP rebate has been paid and the customer fully owns their solar system with no ongoing payments. Connecting batteries to solar carries a separate fee because a technician is required, and SGIP does not cover that connection fee. Apollo asks for a photo of the solar system so a technician can confirm compatibility and provide a quote.
After the single-line drawing is completed, the permit application is submitted and approval can take up to 30–45 days depending on the local agency. Apollo Home Power notifies the customer when the permit is submitted and again when it is approved.
Apollo's SGIP battery installations are typically not connected to the home's solar; they are tied to the grid and are non-export systems. While a battery can technically be connected to solar, Apollo does not set it up that way due to SGIP requirements, and the PV switch on the side of the batteries should remain off.
To prepare a quote for connecting an existing solar system to installed batteries, Apollo Home Power asks for the number of solar panels, the make and model of the existing solar inverter, photos of the inverter, battery system, and related equipment, and proof of ownership of the solar system; compatibility is reviewed and the cost is quoted for customer approval before work begins.
For SGIP-covered battery projects, the cost of the batteries and inverter as well as the labor is covered by the SGIP rebate, which is assigned to the developer. The customer's total cost is $0 with nothing out of pocket or upfront, and Apollo Home Power says it will notify the customer ahead of time if anything changes or if any items are not included.
Apollo Home Power provides battery monitoring login access only after the project is finalized — meaning the SGIP rebate has been paid in full (and, for some projects, after PTO and final rebate payment are received). Customers are notified once payment is received and can then request access.
Connecting a customer's existing solar panel system to batteries installed under the SGIP program is a separate service that is not included in Apollo's SGIP program at no cost. The customer is responsible for any associated costs and service fees, and the work can only proceed after the SGIP incentive is paid and the project is finalized.
Batteries are programmed on an automatic daily charge/standby/discharge schedule set by Apollo Home Power's monitoring team. A typical schedule charges overnight or in the morning, sits in standby midday, and discharges/exports in the late afternoon and evening. Customers can request a different schedule and the monitoring team will reprogram it and confirm the new times.
The PV switch on the battery system is intended for homeowners who want to connect an existing solar system to the battery system. If the existing solar is not connected, the PV switch should remain in the OFF position. Customers are advised not to change any battery hardware or system settings themselves, as only a trained technician should inspect or adjust the system.