NEM 3.0 changed the math on solar in San Diego County. The solar energy you send back to SDG&E now earns far less than the electricity you buy back in the evening, so the value of a solar system depends on how much of its production you use yourself. Battery storage is how most North County homeowners close that gap.
TM Electric and Solar designs and installs battery storage for new and existing solar systems in San Marcos and across San Diego County. Tim, a licensed electrician and U.S. Army veteran in the trade since 1986, personally evaluates your usage, panel, and backup goals — and tells you honestly whether a battery pays off for your home.
Use more of your own solar
Under SDG&E's Solar Billing Plan (NEM 3.0), exported solar earns far less than the retail rate you pay at night. A battery stores daytime production so you use it yourself after sunset instead of selling it cheap and buying it back.
Backup power during outages
Standard grid-tied solar shuts off when the grid goes down. A battery with a properly designed backup configuration keeps your essential circuits — refrigerator, lights, internet, medical equipment — running.
Avoid peak-hour rates
SDG&E's time-of-use plans charge the most in the late afternoon and evening. A battery can cover your home during those hours, which is where most of the savings under NEM 3.0 come from.
What's Included in a Battery Installation
Battery-Only vs. Solar + Battery
Adding a battery to existing solar: If your system is already installed, a battery lets you keep more of its production under current SDG&E billing. We check inverter compatibility and panel capacity first, and if the system is underperforming we'll recommend fixing it before adding storage.
New solar with a battery: Designing panels and storage together lets us size both correctly from day one instead of retrofitting later. See how our solar panel installation in San Marcos works.
Backup-focused systems: If outage protection is the priority, we design around the circuits you need running and confirm your panel can support it — sometimes with a 200-amp panel upgrade in the same project.
How Battery Installation Works
- 1
Usage & Goals Review
We look at your SDG&E bills and ask what matters most: lower bills, outage protection, or both. That decision drives the whole design.
- 2
Battery & Backup Design
We size storage to your evening usage and choose which circuits stay on during an outage. Some homes need a backup loads panel or a main panel upgrade.
- 3
Permits & Interconnection
We pull city permits and file the SDG&E interconnection paperwork for you.
- 4
Installation & Commissioning
We install the system, test backup switchover, set up monitoring, and walk you through how the system behaves during an outage.
Related Services
Solar Panel Installation
Add a battery to a new solar system and design both together.
Learn moreElectrical Panel Upgrades
Many backup systems need a 200-amp panel or a dedicated backup loads panel.
Learn moreSolar Panel Repair
Fix an underperforming system before adding storage to it.
Learn moreEV Charger Installation
Planning an EV? It changes how much storage makes sense.
Learn moreBattery Installation Across North County San Diego
Based at 1175 La Moree Road in San Marcos, we install solar batteries throughout San Diego County, including:
- Solar batteries in San Marcos
- Solar batteries in Escondido
- Solar batteries in Vista
- Solar batteries in Carlsbad
- Solar batteries in Oceanside
- Solar batteries in Encinitas
- Solar batteries in Poway
Solar Battery FAQs
Is a solar battery worth it in San Diego under NEM 3.0?
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For many homes, yes — especially if most of your electricity use happens in the evening. Under NEM 3.0, energy you export to SDG&E is credited at a much lower value than what you pay for grid power at night, so storing your own solar for later use is where the savings are. If your usage is mostly daytime, a battery adds less value. We'll show you the numbers both ways.
How much does a solar battery cost in San Marcos?
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Cost depends on battery capacity, how many circuits you want backed up, and whether your electrical panel needs work. We quote every project from your actual usage and backup goals.
Can I add a battery to my existing solar system?
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Usually, yes. Batteries can be added to most existing grid-tied systems, though compatibility depends on your inverter and electrical panel. We evaluate your current equipment first — even if another company installed it — and tell you the cleanest way to add storage.
Will a battery power my whole house during an outage?
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It depends on battery capacity and your loads. Many homes back up essential circuits like the refrigerator, lights, outlets, and internet. Whole-home backup is possible but often needs more storage and panel work. We design around what you actually need to keep running.
Are there incentives for solar batteries in California?
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The federal residential clean energy credit ended for new expenditures after December 31, 2025. California programs such as the Self-Generation Incentive Program (SGIP) may offer battery rebates depending on funding and eligibility. We'll help you check what's currently available before you commit.
How long do solar batteries last?
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Most home batteries carry manufacturer warranties around 10 years, with performance guarantees on remaining capacity. Actual lifespan depends on how often the battery cycles and how it's configured.
Battery & Solar Guides
Find Out If a Battery Pays Off for You
Send us your SDG&E bill and Tim will give you a straight answer on storage, backup, and savings.