The battery is the part that makes solar work under NEM 3.0.

Why the evening matters

Under Edison’s current time-of-use rates, the most expensive electricity of the day is between 4 and 9 p.m., which is exactly when a solar array is producing the least. Without a battery, you buy that evening power from Edison at the peak rate and sell your midday surplus back for a fraction of it. With a Powerwall, the surplus stays in your garage and runs the house until bedtime.

The exact windows and the published price of every one of them are set out in Edison’s peak hours, and what they cost. It is the clearest way to see why the battery matters here rather than taking our word for it.

When the grid goes down

Heat-wave outages in the High Desert and public safety shutoffs in the foothills are a normal part of summer here. A Powerwall 3 keeps the refrigerator, lights, internet, and, sized right, the air conditioner running without you doing anything. The switch-over takes a fraction of a second.

How long it lasts depends on what you run. A fridge, lights, and Wi-Fi alone can run for a day or more. Central air is the big draw, and we’ll tell you honestly what the battery can and can’t carry for your house before you sign.

What goes in

• BatteryTesla Powerwall 3, with its built-in solar inverter
• Capacity13.5 kWh of usable storage per unit. Larger homes sometimes take two
• Where it goesGarage wall or exterior wall, indoor or outdoor rated
• ControlThe Tesla app shows production, storage, and what the house is using in real time
• Installed byCSLB-licensed partner companies, on the same permit as the panels
• Warranty25 years on parts, workmanship and performance from the installing partner, layered over Tesla’s own manufacturer warranty on the battery

Adding a Powerwall to solar you already have

If you have an older system and no battery, a Powerwall 3 can usually be added. Whether it makes sense depends on your rate plan and your current inverter. Send us a bill and a photo of your existing inverter and we’ll tell you straight whether it’s worth doing.