Solar Generator for a 3-Day Power Outage: How Much? (2026)

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What's in this guide

What a day of essentials costs
Three days, day by day
Ways to stretch three days
How big should the system be?
Battery generator or gas generator?
Which unit to buy

The short answer: for the things that matter in a short outage, a fridge, a few lights, phones, internet and a gas furnace fan, plan on about 3,000Wh a day, or about 1,800Wh a day if you trim it. Across three days that is 5,400 to 9,000Wh. A single Jackery HomePower 3000 holds 3,072Wh, so it covers one day on its own and needs sun, or a bigger system, to cover three.

Most outage guides tell you to “size for your loads”. This page does the reverse: it walks through three days hour by hour, so you can see where the battery goes and what you can do about it.

What a day of essentials costs

These are typical figures. Check the label on your own appliances, and see our sizing guide for the method.

Load	Typical use	Per day
Refrigerator (modern, closed door)	100 to 150W running, about a third of the time	800 to 1,200Wh
Chest freezer	50 to 100W running, about a third of the time	300 to 600Wh
Gas furnace blower and controls	300 to 700W, about 8 hours a day	1,500 to 3,000Wh
Wi-Fi router and modem	20 to 40W, all day	500 to 900Wh
LED lights, five bulbs, five hours	50W	about 250Wh
Two phones and a laptop charging	80W for a few hours	200 to 400Wh
Television, three hours	100W	about 300Wh

A fridge, router, lights and charging come to roughly 1,800 to 2,500Wh. Add a furnace fan in cold weather and you reach 3,000Wh or more. In mild weather, with no furnace, a trimmed day sits near 1,800Wh.

Three days, day by day

The plan below assumes a trimmed 1,800Wh a day in mild weather, and a HomePower 3000 (3,072Wh) with its panels. The sun figures are typical, not guaranteed.

Day	Weather	Used	Panels add	Battery at end of day
Day 1	Clear	1,800Wh	about 1,500Wh	about 2,800Wh
Day 2	Partly cloudy	1,800Wh	about 900Wh	about 1,900Wh
Day 3	Heavy cloud	1,800Wh	about 300Wh	about 400Wh

On a clear start the battery gets through three days with a little to spare. If all three days are grey, the same plan leaves it empty during day three:

Day	Weather	Used	Panels add	Battery at end of day
Day 1	Heavy cloud	1,800Wh	about 300Wh	about 1,600Wh
Day 2	Heavy cloud	1,800Wh	about 300Wh	about 100Wh
Day 3	Heavy cloud	1,800Wh	about 300Wh	empty by mid-afternoon

That second table is the one to plan around, because storms that take the power out are usually the ones that block the sun. If you live somewhere with outages in cloudy seasons, treat the battery as your supply and the panels as a bonus.

Ways to stretch three days

Prioritise the fridge and freezer. Keep doors shut. A closed fridge holds safe temperatures for about four hours without power; a full freezer for about 48 hours. Running the fridge on the battery in short cycles preserves both. See how long a solar generator runs a refrigerator.
Turn the router off overnight. It saves about 250Wh across a night, which is another half hour of fridge time.
Charge phones from the panels in daylight, not from the battery overnight.
Choose warmth carefully. If it is cold, a gas furnace fan is the cheapest way to heat the whole house on battery power. An electric space heater is the most expensive. Our pages on running a furnace and running a space heater show the hours.
Leave big heat loads alone. An electric oven, dryer or water heater can empty a 3,000Wh battery in under two hours. Cook on a camp stove outdoors instead, and see the washer, dryer and stove page for the numbers.

How big should the system be?

Your situation	Daily need	Three-day need	What fits
Fridge, lights, phones, router (mild weather)	1,800Wh	5,400Wh	HomePower 3000 plus panels, or a 5,040Wh 5000 Plus
The above plus a gas furnace fan	3,000Wh	9,000Wh	5000 Plus with panels, or a 3600 Plus with an added battery
Medical gear such as a CPAP or oxygen concentrator	add 300 to 1,500Wh	add 900 to 4,500Wh	Size up, and see the CPAP and oxygen concentrator pages
Well pump or sump pump	add 500 to 2,000Wh	add 1,500 to 6,000Wh	See the well pump and sump pump pages

The HomePower 3600 Plus holds 3,584Wh and expands, and the Solar Generator 5000 Plus holds 5,040Wh, so either gets closer to a three-day plan without sun. Our home backup buying guide lays the three units out side by side.

Battery generator or gas generator?

A gas generator can run for as long as you have fuel, which is its strength in outages of a week or more. It must run outdoors, it is loud, and fuel is hard to find after a storm.

A solar generator is silent, safe indoors and recharges from the sun, but its supply is limited by its size and the weather. For a three-day outage with trimmed use, a battery with panels is usually enough. For a week or more, many households pair a battery for the fridge and phones with a small gas generator as a second source. Our comparison page covers the trade-offs in full.

Check the current price of the HomePower 3000 at Jackery

Which unit to buy

For a trimmed three days in mild weather, the HomePower 3000 with its panels is enough. For a furnace fan, medical gear or a well pump on top, step up to the 5000 Plus or a 3600 Plus with extra battery. Start from your own list of loads, add them up, and multiply by three.

Jackery's full lineup and current prices

Keep reading: Best solar generators for home backup · How to size a solar generator · Can a solar generator power a whole house? · How many panels charge a HomePower 3000 · Solar generator vs gas generator · Solar generator for a chest freezer

Home backup systems

A well pump or central AC needs a 240V system.

System	Battery	Output	Runs 240V	Price	Suited to	Retailer
Jackery HomePower 3000Everyday essentials	3,072Wh	3,600W	No	$1,989	Fridge, Wi-Fi, lights, phones and a CPAP for one to two days.	See price at Jackery
Jackery HomePower 3600 PlusLonger outages	3,584Wh	3,600W	No	See site	The essentials plus a furnace blower or a window AC, over several days.	See price at Jackery
Anker SOLIX F3800 Plus kit240V, mid-size	Expandable	120V / 240V	Yes	$3,500	A well pump, water heater or central AC that needs 240V.	See price at Outbound Power
EcoFlow DELTA Pro Ultra kitLargest capacity	6,144Wh	7,200W	Yes	$4,782	The largest battery and solar input of the four, for long outages and whole-home setups.	See price at Outbound Power

Prices as last checked. Affiliate links: we may earn a commission at no cost to you.

Common questions

How big a solar generator do I need for a 3-day power outage?

For essentials only (a fridge, a few lights, phones, internet and a gas furnace fan), plan on about 3,000Wh a day if you do nothing to save power, or about 1,800Wh a day if you trim it. That is 5,400 to 9,000Wh over three days. A single 3,072Wh battery covers one day alone, so a three-day outage needs either solar panels to refill it each day or a larger or expandable setup.

Can solar panels keep a battery going for three days?

Partly. A typical set of panels adds about 1,000 to 2,500Wh on a clear day and as little as 200 to 500Wh on a heavy overcast day. If your daily use is near 1,800Wh and the sun is out, panels can close most of the gap. In a grey three-day storm, which is when outages usually happen, plan on the battery doing most of the work.

What should I power first in a long outage?

Food safety, communication and heat, in that order. A refrigerator uses roughly 1,000Wh a day and keeps food safe, phones and internet are a few hundred, and a gas furnace fan adds roughly 300 to 700W while it runs. Lights are cheap. Anything that makes heat from electricity, such as a space heater, oven or dryer, comes last because it empties the battery in hours.

Is one solar generator enough for a week-long outage?

Rarely, unless you cut use hard. A week at 1,800Wh a day is about 12,600Wh. That takes a large, expandable system with panels, or a plan that uses the battery for the fridge and phones only and the sun for the rest. For multi-day winter outages, a gas generator as a second source is a sensible backup.

How do I make a battery last longer in an outage?

Keep the fridge door shut, set it a few degrees warmer if food allows, run it in the cooler part of the day, use LED lights, charge phones during the day from panels, and turn the internet router off at night. These habits typically cut daily use by a third or more.

Should I buy a bigger battery or more solar panels?

For a three-day outage, a bigger battery protects you on the grey days and panels recover the charge on the sunny ones, so you want both. If you can only spend on one, buy the battery: panels without enough storage leave you in the dark overnight, and a full battery with no panels still gets you through a day or two.

Important notice

Important Notice

The information on this page is provided for general educational purposes only and reflects publicly available data at the time of publication. Solar incentives, tax credits, rebates, utility programs, installer availability, and pricing change frequently and may differ in your specific situation. We make no guarantee that the information is current, complete, or accurate for your circumstances.

This is not tax, legal, financial, or professional advice. Always verify current federal, state, and local incentive eligibility with the official program administrator, the IRS, and a qualified tax professional before making purchase or financing decisions.

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