How Long Will It Run

How long will an Anker SOLIX X1 last in a power cut?

A full Anker SOLIX X1 (5 kWh usable) runs the fridge-freezer, heating controls, broadband, lights and phones for about 20 h 18 min in an American home with a gas furnace. Running the whole house as normal, it lasts about 3 h 43 min.

Starting at a 20% reserve, the same essentials get about 4 h 4 min. Backup needs Anker's Backup Controller, which switches the house over in under 10 milliseconds. Batteries stack in 5 kWh modules, up to six on one power module.

The specifications that matter in a power cut

Usable energy
5 kWh per unit
Continuous output
6 kW
Peak output
10 kW. For 10 seconds, on the 5 and 6 kW power modules.
Backup
Whole house, with the gateway (X1 Backup Controller)
Solar during a cut
Not stated
Units per system
Up to 6
Chemistry
LFP (lithium iron phosphate)
Warranty
10 years
Sold in
the US

Source: maker's datasheet, read 2026-09-26. Anker's own power module and battery module datasheet (May 2024), hosted by a reseller.

One, two or three of them

American home · starting full · typical case · no solar
What it runsOneTwoThree
Fridge, internet, lights and phones44 h 8 min3 days 16 h5 days 12 h
The essentials, with the heating20 h 18 min40 h 36 min2 days 13 h
Essentials, heating, cooking and TV16 h 43 min33 h 26 min2 days 2 h
The whole house, as normal3 h 43 min7 h 27 min11 h 10 min
American home · typical case · no solar
What it runsFullHalf fullAt a 20% reserve
Fridge, internet, lights and phones44 h 8 min22 h 4 min8 h 50 min
The essentials, with the heating20 h 18 min10 h 9 min4 h 4 min
Essentials, heating, cooking and TV16 h 43 min8 h 22 min3 h 20 min
The whole house, as normal3 h 43 min1 h 52 min44 min

What it can run at once

Energy decides how long; output decides what. One Anker SOLIX X1 supplies 6 kW continuously, so the essentials are easy but a big heater, a kettle or a car charger on top can be too much. Motors and compressors also need a start-up surge.

American figures · against 6 kW continuous and 10 kW peak
Add this to the essentialsEverything at onceOne SOLIX X1
Microwave, 1,000 W output2.3 kWYes
Space heater, 1,500 W2.3 kWYes
Window air conditioner, 12,000 BTU1.9 kWYes
Sump pump1.6 kWYes
Well pump (1/2 hp)1.8 kWYes
Electric car (3-pin "granny" charger)2.2 kWYes

Solar in a power cut

The panels connect through the same hybrid inverter, but the datasheet does not say outright that solar charges it during a cut.

With 7 kWp of panels (Atlanta, 33.7°N), an average day's sun covers the essentials in every month. These are averages. A week of thick cloud, common in a British winter, can cut the panels to a fraction of this, so in the darker months plan on the battery alone and count the sun as a bonus.

Essentials with heating · a 7 kWp array · Atlanta, 33.7°N · an average day's sun ("keeps going" means the panels cover a day's use)
MonthStarting full
JanKeeps going
FebKeeps going
MarKeeps going
AprKeeps going
MayKeeps going
JunKeeps going
JulKeeps going
AugKeeps going
SepKeeps going
OctKeeps going
NovKeeps going
DecKeeps going

Do solar panels work in a power cut? explains why most systems stop, and what keeps them going.

How full is it when the power goes?

A home battery spends most days charging and discharging to save money, so a power cut finds it at whatever level it happens to be. In the evening in winter that can be close to empty. Most systems let you set a backup reserve that the battery will not use on ordinary days (Tesla calls it Backup Reserve; GivEnergy's app has a similar minimum charge for its emergency supply). The tables here show a full battery, a half-full one, and one sitting at a 20% reserve.

If a storm is forecast, charge it to full. Tesla's Storm Watch does this automatically when a weather warning is issued for your area; on other systems you raise the reserve or force a charge in the app.

No home battery? A power station for the essentials

A portable power station does the same job for the things that plug in, without an installer. The biggest ones hold a third to a half of a home battery. Here is how long each runs the fridge-freezer, the heating, the broadband, the lights and the phones, starting full:

Typical case · Essentials with heating
Power stationCapacityUK homeUS home
Zendure SuperBase V64006,438 Wh40 h 34 min19 h 50 min
EcoFlow DELTA Pro Ultra6,144 Wh39 h 47 min19 h 43 min
Jackery Explorer 5000 Plus5,040 Wh34 h 48 min16 h 41 min
Zendure SuperBase V46004,608 Wh31 h 13 min15 h 7 min
EcoFlow DELTA Pro 34,096 Wh27 h 45 min13 h 26 min

The boiler or furnace is the catch: it is usually wired in, not plugged in, so a power station can only run it through a socket or a changeover switch an electrician fits. The boiler guide and the furnace guide explain how. Each station page has the full numbers and where to buy it.

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These are estimates from the site's model, not a maker's claim: stored energy × 94% through the inverter ÷ (what the house draws on average + about 30 W for the battery system itself). The sum is explained here.