Multi-Device Load Builder

Sizing one device at a time misses the real household load. Pick everything you need to keep running, set your hours, and get the full picture: total watts, daily watt-hours, runtime by battery size, and the capacity to shop for — with fridge duty cycles handled for you.

Build your load

Add quantities for every device in your plan — totals update as you go. Typical wattages come straight from our Device Wattage Library.

One target window for the whole plan — an evening outage is 4–8 hours, overnight is about 12.
Filters the list below — devices you’ve already added stay in your totals either way.

Connectivity & internet

Wi-Fi router 10W
Modem 8W
Router + modem combo 15W
Mobile hotspot 5W
Satellite internet terminal 75W
Starlink Mini-style satellite internet terminal 30W

Computing & work

Laptop 50W
Gaming laptop 160W
Portable monitor 10W
External hard drive 8W

Small electronics

Smartphone 10W
Tablet 18W
LED light 8W
Camera battery charger 10W
Gaming handheld 25W
USB-C charger (phone/laptop) 45W
Portable projector 60W

Comfort

Small fan 30W

Appliances

Mini fridge Surge 60W · ~30W avg (50% duty)
Full-size refrigerator Surge 150W · ~60W avg (40% duty)
Sump pump Surge 800W
Small TV 40W

Health devices

CPAP-style device Medical 40W

Wattages are typical figures from the Device Wattage Library — your models may differ. Runs entirely on this page; your plan is never sent or stored.

PF-05Multi-device loadResult card
RSV · Reserve gauge Scale · % of recommended

533 Wh

GO

To run 2× Smartphone, 1× Router + modem combo, 2× LED light for 8 hours (8 hr), shop for stations rated around this figure or higher.

Running watts, all on at once 51 W
Duty-cycle average draw 51 W
Energy over your window 408 Wh
Daily consumption (24 hr) 1,224 Wh
Minimum energy needed 480 Wh
Capacity class 500–1,000Wh

“Energy over your window” and “daily consumption” are what your devices draw before conversion losses; “minimum energy” grosses the window up for inverter losses, and the headline number adds the 10% planning reserve.

What this class typically looks like: toolbox-size stations that can run several devices at once for a day or more. Compare stations in this class.

ASSUMPTIONS INVERTER EFF 85% RESERVE 10% ADDED DUTY CYCLE FRIDGES ONLY FORMULA W × h ÷ eff ÷ (1−rsv)
Estimates only — see the disclaimer below Form PF-05A

Runtime by battery size

300 Wh class ~4 hr 30 min
500 Wh class ~7 hr 30 min
1,000 Wh class ~15 hr
2,000 Wh class ~30 hr

Same shared formula as the Battery Runtime Calculator — your duty-cycle average draw against each class, with 85% inverter efficiency and a 10% reserve held back.

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How this is calculated

The builder sums your devices, then hands the totals to the same shared calculation library as every other tool on this site:

runningWatts = Σ (deviceWatts × quantity) averageWatts = Σ (deviceWatts × dutyCycle × quantity) requiredWh = (averageWatts * desiredHours) / (efficiency / 100) recommendedWh = requiredWh / (1 - reserve / 100)

In plain English: running watts is everything switched on at once — the number a station’s continuous AC output rating must beat. Average watts applies a duty cycle where our library has one (currently the two fridges: 50% for a mini fridge, 40% for a full-size refrigerator, in line with the Department of Energy’s guidance that compressors run roughly a third to half the time). Energy needs are sized from the average, grossed up for inverter losses, and topped with a planning reserve — exactly the Power Station Sizing formula. The runtime-by-size rows use the Battery Runtime formula unchanged.

Default assumptions

  • 85% efficiency — a typical figure for AC output through an inverter. Direct USB-C or 12V DC output loses less.
  • 10% reserve — headroom for battery aging, cold weather, and estimate error, so the recommendation survives contact with reality.
  • Duty cycle only where we have data — every device without published duty data counts at full running watts, which leans toward recommending slightly more capacity rather than less.

The full method — and why we picked these defaults — is on How we estimate.

What to do with this number

Compare stations in your class Check one device’s wattage Size a single device instead

Some links on this page may be paid links. If you buy through them, Cynosure LLC may earn a commission at no extra cost to you. We do not claim to have personally tested products unless clearly stated.

Backup power stations by capacity class

Once your plan has a watt-hour target, compare every station in our catalog — smallest to largest — on output, weight, and price. Prices last checked between 2026-07-08 and 2026-07-09.

Some links on this page may be paid links. If you buy through them, Cynosure LLC may earn a commission at no extra cost to you. We do not claim to have personally tested products unless clearly stated.

Backup power stations, small to XL
Product Capacity Output Ports Weight Est. price Ideal for Link
EcoFlow RIVER 3 Portable Power Station EcoFlow 245Wh 300W AC 3× AC outlet (300W, 600W X-Boost), USB-C, USB-A, Car port 8.4 lb $149–$219 Keeping a router, modem, phones and small electronics running for hours, A light, grab-and-go outage or travel unit, Fast recharge with sub-20ms UPS passthrough See current price
Jackery Explorer 300 Plus Portable Power Station Jackery 288Wh 300W AC AC ×1 (300W, 600W surge), USB-C ×2 (100W max), USB-A ×1, 12V car port 8.27 lb $200–$300 Router and modem backup for a workday, Charging phones and tablets for days, A laptop for a few hours via the 100W USB-C port, Car trips and short outages See current price
Jackery Explorer 600 Plus Portable Power Station Jackery 632Wh 800W AC AC ×2 (800W total, 1600W surge), USB-C 100W, USB-C 30W, USB-A 18W, 12V car port 16.1 lb $300–$500 A full laptop workday plus phone charging, A day or more of router and modem backup, Weekend camping electronics, Fans, lights, and a CPAP-class device together See current price
EcoFlow DELTA 2 Portable Power Station EcoFlow 1,024Wh 1,800W AC 4× AC outlet (1800W, 2700W surge), 2× USB-C (100W), 2× USB-A, Car port 27 lb $499–$999 Carrying a fridge plus electronics through a multi-hour outage, Home backup you can expand later (to 2048Wh+ with add-on batteries), Fast recharge — roughly 0–80% in under an hour See current price
Anker SOLIX C1000 Portable Power Station Anker 1,056Wh 1,800W AC AC ×6 (1800W total, 2400W surge), USB-C 100W, USB-C 30W, USB-A ×2 (12W), 12V car port (120W) 28.4 lb $400–$650 Multi-day phone and internet backup, A full-size or mini fridge in duty cycles (1800W continuous, 2400W surge), Family camping trips with several devices at once, Fast top-ups between outages — 80% in 43 minutes from the wall See current price
Jackery Explorer 2000 v2 Portable Power Station Jackery 2,042Wh 2,200W AC AC ×3 (2200W total, 4400W surge), USB-C 100W, USB-C 30W, USB-A 18W, 12V car port (120W) 39.5 lb $700–$1,100 Days of essentials during long outages, A full-size refrigerator in duty cycles, High-draw devices up to 2,200W, Sub-20ms switchover keeps a router or NAS online when the grid drops See current price

Prices last checked between 2026-07-08 and 2026-07-09

Specific products picked for each class — we haven't hands-on tested them, so verify capacity, continuous output, and surge ratings on the current listing. Commissioned links, at no extra cost to you.

Keep planning

Best picks by scenario

CPAP, sump pump, RV & vanlife, Starlink — the load math on those pages is this builder’s, already worked.

Choose a power station without overspending

A step-by-step way to match capacity to your real needs instead of paying for watt-hours you will never use.

How many watts does a refrigerator use?

Running vs surge vs average watts — the duty-cycle math this builder applies to fridges, explained in full.

Hurricane season power prep

Sizing a whole-household outage plan while the sky is clear — essentials first, fridge math second.

Frequently asked questions

Does "running watts" mean everything is on at the same time?

Yes — the running-watts total assumes every device in your plan draws at once, which is the number to check against a station’s continuous AC output rating. The duty-cycle average is lower because compressor loads like fridges only run part of the time, and that average is what determines how many watt-hours you need.

How is the duty-cycle math applied?

Only where our Device Wattage Library has duty data — currently the two fridges. A mini fridge counts at 50% of running watts and a full-size refrigerator at 40%, consistent with the Department of Energy’s guidance that compressors run roughly a third to half the time. Every other device counts at its full typical running watts, which errs on the side of recommending slightly more capacity rather than less.

Can I save or share my plan?

Yes — your device list and hours are written into the page address as you edit, and the "Copy link to this plan" button puts that address on your clipboard. Nothing is sent to or stored on our servers; the plan lives entirely in the link.

Why is the recommended size bigger than watts × hours?

Two honest adjustments. Converting battery power to AC through an inverter typically consumes about 15% of the energy, so we divide by 85% efficiency. Then we add a 10% planning reserve for battery aging, cold weather, and estimate error. Both assumptions are published and adjustable in the single-device Power Station Sizing Calculator.

Calculations are estimates only. Real runtime depends on battery age, inverter efficiency, device behavior, temperature, surge loads, manufacturer limits, and actual measured wattage. Always verify product specifications before buying or relying on a setup.

Affiliate disclosure

Some links on this page may be paid links. If you buy through them, Cynosure LLC may earn a commission at no extra cost to you. We do not claim to have personally tested products unless clearly stated.