Powerwall 3 Is Sold at Four Output Ratings. Which One You Get Decides What Runs in an Outage
Summary
Tesla's datasheet lists Powerwall 3's nominal AC output as 5.8, 7.6, 10 or 11.5 kW, with maximum continuous current of 24, 31.7, 41.7 or 48 A. The energy is the same 13.5 kWh in every case; the rating is set at installation to match the breaker and conductors. A fifth figure, 15.4 kW of continuous off-grid discharge, is available only when the on-grid rating is 11.5 kW and the unit is installed with an 80 A breaker. The rating does not change the 185 LRA motor-start figure or the 20 kW DC of solar the unit accepts.
The four ratings
| On-grid rating | Maximum continuous current | What it is close to |
|---|---|---|
| 5.8 kW | 24 A | a 30 A circuit |
| 7.6 kW | 31.7 A | a 40 A circuit |
| 10 kW | 41.7 A | a 50 A circuit |
| 11.5 kW | 48 A | a 60 A circuit |
The circuit column is our reading of the current figures against standard breaker sizes; the datasheet gives the current and leaves the breaker to the installer, except for the 80 A it specifies for the 15.4 kW off-grid option.
Why a 13.5 kWh battery might only deliver 5.8 kW
Energy and power are separate limits, and the power limit is what your home's electrical service and the installer's wiring allow. A smaller rating means fewer simultaneous loads: at 5.8 kW, a 3.5 kW air conditioner and a 2 kW oven are already at the ceiling; at 11.5 kW they leave room for the rest of the house. The datasheet's 185 LRA load-start figure applies regardless of the rating.
The off-grid 15.4 kW option
Footnote 3 on the datasheet: 15.4 kW off-grid maximum continuous discharge is available only if the on-grid rating is 11.5 kW, and if enabled the Powerwall must be installed with an 80 A breaker and appropriately sized conductors. That is a one-third increase over the on-grid figure for the duration of an outage, and it has to be designed in from the start.
Charging has its own ceiling
A Powerwall 3 on its own charges at up to 5 kW (20.8 A AC); with up to three expansion units attached, at up to 8 kW (33.3 A AC). Solar enters on the DC side through six MPPTs, 60 to 480 V and 15 A each, up to 20 kW; our earlier guide covers the solar input and expansion in detail.
What to ask for on the quote
The on-grid output rating, the breaker size, whether the 15.4 kW off-grid option is enabled, and the solar-to-home efficiency path you care about: the datasheet gives 97.5% for solar straight to the home and 89% for solar through the battery to the home, both at 25 °C and beginning of life.
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Sources
We have not tested these products. Specs, prices, stock and terms are as published on these pages on the date above and can change; check the manufacturer or retailer before you buy.