Outage Ready: a 2-day outage

Two days without power: battery size, how much solar refills it, and when to trim loads.

Published October 30, 2026 · Updated November 2, 2026

Quick answer

Two days of our example essentials is about 4,650 Wh, or about 6,300 Wh of rated battery with no recharging. Solar cuts that a lot: a 2kWh battery plus about 500W of panels can keep up on sunny days if you trim loads.

Key points

About 4,650 Wh usable over 48 hours.
Solar refill is the usual way to stretch a battery.
Trim the fridge and laptop first.

What a typical home keeps running

Our example essentials list. Swap in your own devices in the Power Planner.

Device	Example draw	Wh/day
Refrigerator (EnergyGuide 550 kWh/yr example)	≈63 W average	1,507
Wi-Fi router + modem	15 W	360
LED lights, 4 × 10 W for 5 h	40 W	200
Phones (2), charging	10 W for 2 h	20
Laptop	60 W for 4 h	240
Total		2,327

Battery size for 2 days

Energy needed: 2,327 Wh/day × 48 h ÷ 24 ≈ 4,654 Wh usable. Divide by 0.736 (our estimate: 80% usable depth from Victron LiFePO4 data × 92% inverter efficiency from the NREL PVWatts manual; an estimate for power stations) to get about 6,323 Wh of rated capacity with no recharging.

With no recharge, you need a large expandable system. With solar, a 2kWh system can cycle daily.

Option	Rated Wh	Covers the plan?
DELTA 3 + extra batteries	Up to 5,000	Close, without recharge
2kWh battery + 500W solar	≈2,000 + solar	Yes on sunny days (estimate)

Solar or a generator?

As an example, 500W of panels in a place with 4 peak sun hours, with the PVWatts V1 total derate of 0.77 (NREL PVWatts manual), makes about 1,540 Wh a day. That's an estimate; check your location with NREL PVWatts. See peak sun hours and generator vs battery backup.

A small inverter generator is the fallback for cloudy days. Run it outdoors only.

Food and safety checklist

FoodSafety.gov: an unopened fridge keeps food safe for about 4 hours; a full freezer about 48 hours (24 if half full).
Keep a flashlight and a battery radio that don't depend on the power station.
Run any generator outdoors, far from doors and windows. The CDC warns that generator exhaust can kill.
Never connect anything to home wiring without a transfer switch or interlock fitted by a licensed electrician.

Picks for this plan

EcoFlow DELTA 3 (1,024Wh)

Expandable up to 5kWh; 500W solar input.

Check price on Amazon

Renogy 200W solar panel

A rigid 200W panel; check the station's solar input voltage limits before wiring panels together.

Check price on Amazon

FAQ

Is it better to buy a bigger battery or add solar?

For multi-day outages, solar usually gives more energy over time, but only in daylight. A bigger battery is predictable at night and in storms.

Where do I go next?

Try the power planner to put numbers to your own situation, or see the product picks on the deals page.

Terms used here

Watt (W): Rate of power use or production.
Watt-hour (Wh): Energy: one watt for one hour.
Kilowatt-hour (kWh): 1,000 watt-hours.
Depth of discharge (DoD): Share of a battery's capacity that is used.
LiFePO4 (LFP): Lithium iron phosphate battery chemistry.
Inverter: Converts DC battery power to AC household power.
Peak sun hours: Hours of equivalent 1,000 W/m² sunlight per day.
Derate: Factor for real-world losses in solar output.
Transfer switch: Device that isolates home circuits from the grid during backup.

Sources

This guide is informational and based on published specifications and general references, not hands-on testing. Check the manufacturer's current specs before you buy.