Tesla Powerwall 3 in California
What it is, what it costs installed, and whether it is the right battery for your house.
The Tesla Powerwall 3 is a home battery that Tesla publishes as 13.5 kWh of usable capacity with 11.5 kW of continuous output. That is the highest continuous output of the four platforms we work with, which is what determines how much of your house can run at once when the grid goes down.
The difference between Powerwall 3 and earlier generations is that the solar inverter is built into the battery rather than sitting on the wall as a separate box. For a new solar and storage system that means fewer components, one less thing to fail, and a simpler install. For an existing solar system it means the integration depends on the inverter you already have.
A battery does two jobs. The first is financial. Under NEM 3.0 your utility pays you far less for exported power than it charges you at peak, so storing your own generation and using it in the evening is worth more than selling it. The second is backup. When the grid fails, the system switches over automatically.
Tesla rates a single Powerwall 3 to support up to 20 kW DC of solar, and systems scale to four units with up to three Expansion units, for a maximum of seven units on one site.
What the numbers mean
Six things worth knowing
-
13.5 kWh
Usable capacity
Tesla's published figure. Enough to carry most California homes through the evening peak, and through a typical overnight outage on essential loads. Expansion units add 13.5 kWh each without a second full Powerwall.
-
11.5 kW continuous
Output power
The highest continuous output of the four platforms we work with. Output power, not capacity, is what decides whether you can run air conditioning or an electric range during an outage rather than just lights and a fridge.
-
Built in
Solar inverter
The solar inverter is inside the battery. On a new solar and storage build that removes a separate component from the wall and from the bill of materials. It also means retrofit details depend on your existing equipment.
-
185 A LRA
Motor start
Tesla rates the load start capability at 185 locked rotor amps, which is what a battery needs to bring a large air conditioning compressor online. Tesla states a single unit can support the power needs of most homes.
-
Storm Watch
Weather charging
The system monitors weather data and charges ahead of forecast severe weather, so the battery is full before an outage rather than partway through one. It is a small feature that matters during PSPS season.
-
10 years
Warranty and app
Tesla warrants Powerwall 3 for 10 years, and the datasheet notes the unit must be reliably connected to the internet to secure the full term. The Tesla app shows generation, consumption and battery state in real time.
Full specifications
| Usable capacity | 13.5 kWh per unit |
|---|---|
| Continuous output | 11.5 kW, configurable from 5.8 kW |
| Off-grid discharge | Up to 15.4 kW, configurable, conditions apply |
| Motor start | 185 A LRA |
| Charge power | 5 kW, or 8 kW with Expansions |
| Chemistry | Lithium iron phosphate (LFP) |
| Coupling | DC, with integrated solar inverter |
| Max solar input | 20 kW DC, 6 MPPTs |
| Scales to | 4 Powerwall 3 units plus 3 Expansions, 7 total |
| Efficiency | 89% solar to battery to home |
| Warranty | 10 years, internet connection required |
| Operating range | -4°F to 122°F, derated above 104°F |
| Dimensions | 43.5 x 24 x 7.6 in, 291 lb installed |
Per the Tesla Powerwall 3 datasheet, US edition, model 1707000-xx-y. Last reviewed 12 August 2026.
Being straight about it
When Powerwall 3 is not the right answer
- You have working solar you do not want touched. The integrated inverter is an advantage on a new build and a complication on a retrofit. FranklinWH aPower 2 is AC-coupled and works alongside almost any existing inverter instead.
- You already run SolarEdge equipment. The SolarEdge Home Battery is DC-coupled into a system you already have, which avoids a conversion step and keeps more of your generation.
- You want more than 13.5 kWh in one unit. FranklinWH aPower 2 is 15 kWh per unit, and Lunar scales in 5 kWh blocks up to 30 kWh in a single tower.
- You want the longest warranty. Tesla is 10 years. FranklinWH is 15 and Lunar is 12.5. If you plan to cycle the battery hard every day, that gap is worth weighing.
- Your internet is unreliable. Tesla's datasheet states the unit must be reliably connected to secure the full 10-year warranty, and cellular is not intended as the primary connection.
Cost
What it costs, honestly
We do not publish a price, because a number without your bill attached is a guess. The installed cost of any battery depends on how many units you need, how much work your electrical panel requires, how far the battery sits from it, and which programs you qualify for where you live.
What we can tell you is that the federal 30% residential clean energy credit under Section 25D expired on 31 December 2025, so a cash or loan purchase in 2026 receives no federal credit. What is left depends entirely on your utility, and the amounts vary widely between PG&E, SCE, SDG&E, SMUD, LADWP and the community choice aggregators. Send us a recent bill and we will tell you exactly what is open where you live.
Questions
Tesla Powerwall 3 questions
How much does a Tesla Powerwall 3 cost in California?
We do not publish a price, because a number without your bill attached is a guess. The price depends on how many units you need, what work your electrical panel requires, the distance between the battery and the panel, and which incentives you qualify for where you live.
How many Powerwalls do I need?
Most California homes are served by one or two. The number depends on your evening consumption, whether you want whole-home or essential-loads backup, and whether you run large loads such as air conditioning or an EV charger. Systems scale to four Powerwall 3 units with up to three Expansions.
How long will a Powerwall run my house in an outage?
It depends entirely on what you run. Essential loads such as the fridge, lights, internet and outlets last far longer than air conditioning or electric heat. We size the system around what you actually want backed up rather than a headline number.
Can I add a Powerwall 3 to solar I already have?
Usually yes, but the integrated solar inverter makes the details depend on your existing equipment. On some retrofits an AC-coupled battery such as the FranklinWH aPower 2 is the cleaner answer. We check what you have before recommending anything, and we will tell you if a different platform fits better.
Does the Powerwall 3 work without solar?
Yes. On a time-of-use rate plan a battery can charge from the grid when power is cheap and discharge at peak. Whether that alone justifies the cost depends on your rate plan and your usage pattern, and we will tell you if it does not.
What is the warranty on a Powerwall 3?
Tesla warrants Powerwall 3 for 10 years. The datasheet notes the unit must be reliably connected to the internet to secure the full term, and that cellular should not be used as the primary connection. Read Tesla's warranty document for the full conditions before you buy.
Is the Powerwall 3 safe?
It is certified to UL 9540 and UL 9540A among other standards, and it uses lithium iron phosphate cells, which are more thermally stable than the NMC chemistry in some competing batteries. Every home battery in California is also permitted through your local building department, which involves an inspection before the system is placed in service.
Do I need a permit for a home battery in California?
Yes. A building permit and utility interconnection approval. We manage both, along with the schedule, so you are not chasing your city's permitting office or your utility.
What is Storm Watch?
A Tesla feature that monitors weather data and charges the battery ahead of forecast severe weather, so you enter an outage with a full battery rather than whatever happened to be left. It is genuinely useful during Public Safety Power Shutoff season.
Do you install it?
No. We do not install solar or batteries. We specify your system, secure the incentives and rebates you qualify for, and manage the project. We have partnered with experienced installers across California who handle the fulfillment.
Next step
Is Powerwall 3 right for your house?
Send us a recent utility bill. We will read your real usage and rate plan, check what your utility currently offers, and tell you which of the four platforms fits. Including when the cheaper one is the right answer.
Solari Storage is a California battery sales and program-qualification company. We do not install solar or batteries. Our install partners handle fulfillment.