Inverter Size vs Your Load: Pick the Right Watts

Continuous and Peak Output on a Listing

A power station listing usually states a wattage figure for the AC output from the inverter. Many listings carry two figures: a continuous output, sometimes called rated output, and a peak output, sometimes called surge. The continuous figure is the level the inverter can supply for an ongoing load; the peak figure is the short-duration maximum it can handle when an appliance first starts.

The EIA's page on measuring electricity explains that watts are the unit used for the power that devices draw. Some devices need only a few watts, while others need more. The wattage on a listing is the same unit; a figure like "1,500W" means 1,500 watts of AC output.

Two related terms come up on the same listing:

• Continuous output, also called rated output, for the sustained level
• Peak output, also called surge, for the brief starting moment
• Watt-hours for battery capacity, a separate figure covered in power station watts versus watt-hours

How Appliances Draw Power

Appliances fall into two broad groups for this question. Resistance loads, like lights and heaters, draw a fairly steady amount of power while they are on. Motor loads, like a refrigerator, an air conditioner, or a pump, draw more at the moment they start, then settle to a lower running draw.

That starting moment is what the peak figure is for. When you read the appliance label, look for the wattage; some labels also state a starting or locked-rotor figure for motors. Compare the running draw with the continuous output and the starting draw with the peak output. Read the label for exact numbers, because draws vary by model and age.

The inverter on a power station converts stored battery power to AC for those appliances. The total output watts article explains how the inverter's figure relates to the outlets on the unit.

Read the Appliance Label

The nameplate label on an appliance lists watts, or amps and volts that you can multiply to get watts. The EIA page on measuring electricity is a useful reference for how those units relate. Write down the running draw for each appliance you plan to connect, and the starting draw for any motor-driven one.

The maker's manual for the power station states its own figures and limits. Read that manual alongside the appliance labels. This article can explain the terms, but only the label and the maker's page give the figures for your specific units.

Why This Site Does Not Size a Home

The buying guides on this site compare listings on the stated details: wattage, capacity, outlet count, battery chemistry, and the rest. The guides cannot promise that a particular wattage runs a particular appliance, because draws vary by model and because a home's combined load depends on what you connect at the same time.

For a hard answer about your own load, read the appliance labels, check the maker's page, and ask a licensed electrician where wiring is involved. The Florida Division of Emergency Management's Plan & Prepare page and the National Weather Service's hurricane safety page both point to preparing before the season begins.

Comparing Two Listings

When a listing states both figures, compare the continuous figure with the running draw you expect and the peak figure with the starting draw of the largest motor. If a listing gives only one figure, treat it as the continuous output and look for a separate peak statement in the bullets or on the maker's page.

Also read the outlet count. AC outlets determine how many cords you can plug in, and the inverter wattage determines what those outlets can supply together. Some makers, like Anker in its SOLIX line, state a continuous figure and a separate peak figure in the listing, which is the pattern to look for.

The portable power station guide compares units on these stated details side by side.

Output and Capacity Are Separate Figures

A listing shows the inverter output in watts and the battery capacity in watt-hours. The watt figure says how much power the inverter can supply at a moment; the watt-hour figure says how much energy the battery holds. Both matter for a purchase, but they answer different questions: the output determines what you can connect, and the capacity determines how long the battery can supply it, subject to the maker's stated limits.

The guide on power station watts versus watt-hours explains the distinction in more detail. When you compare two listings, check both figures and read the maker's page for the conditions it states.

What to pick for your situation

Questions

What does continuous output mean on a power station?

It is the sustained AC wattage the inverter can supply for an ongoing load. Compare it with the running draw on your appliance labels.

What does peak output mean?

It is the short-duration maximum for motor starts. Compare it with the starting draw of the largest motor you connect.

Do I need the peak figure to match every appliance?

Only the largest starting draw matters for the peak figure. Smaller motors start at lower draws, but read the labels because draws vary by model and age.

How do I find my appliance's wattage?

Read the nameplate label. It lists watts, or amps and volts that you multiply to get watts. The EIA's measuring electricity page explains the units.

What if a listing shows only one wattage figure?

Treat it as the continuous output and look for a separate peak statement in the bullets or on the maker's page.

Does a higher peak output mean a better unit?

Not by itself. The continuous output matters for sustaining a load, and the battery capacity in watt-hours matters for how long the unit runs. Those are separate figures on a listing.