Running Multiple Devices from a Power Station: Total Load

Two watt figures on a power station listing

A power station listing usually carries two kinds of watt figures that are easy to mix up. Watts measure the rate at which electricity moves; the U.S. Energy Information Administration explains that electricity is measured in units of power called watts. The battery capacity in watt-hours is a separate figure. It describes the stored energy in the station, not the fastest rate at which the station can deliver it.

The figure that sets how many devices you can run at once is the AC output rating. Some listings also show a surge or peak figure, which is a brief higher rate allowed when a device starts. The two figures answer different questions, and the maker's page for each model should state both, as explained in the continuous versus peak comparison.

• AC output: the continuous watt figure for the inverter
• Surge or peak: the brief starting figure, when the listing gives one
• Battery capacity in watt-hours: the stored energy, not the output rate

Adding the running watts of devices you run at once

Total load means the sum of the running watts of every device you expect to run at the same moment. A lamp, a router, a refrigerator and a television each needs its own watts while running. The figure for each device is on the device's rating label or in its manual, not on the power station listing. The station listing states how many watts the AC output can supply, so the comparison is arithmetic: add the device figures and keep the total under the station's continuous output figure.

The site does not publish wattage numbers for household devices, because models differ and the maker and a licensed electrician decide a home's sizing. The inverter rating versus battery capacity article explains why the output figure and the capacity figure are not interchangeable.

• Read the station's AC output figure on the listing.
• List the devices you will run at the same time, not every device you own.
• Read the running watts for each device on its rating label.
• Add the running watts and compare the total with the AC output figure.
• If the total sits at or above the figure, drop a device or look at a station with a larger output figure.

The AC output figure as the ceiling for the total

The continuous AC output figure is the ceiling for the total you add up. Devices with motors or compressors, such as a refrigerator, draw more power for a moment when they start, which is why a listing may also show a surge figure. Keeping the added running total below the continuous output figure leaves room for that startup moment without pushing the sum past the rating.

The site does not size a home or name the watts a device needs. Read the rating label on each device and ask the maker and an electrician about what fits the station you are considering.

Overload protection as a listing feature

Many power station listings name overload protection as a feature. The term describes the unit cutting or limiting AC output when the demand goes beyond what the inverter can supply. It is a listing word, not a promise about what one model does at one load; the maker's manual gives the details for that model.

Keeping the total below the stated AC output figure means the protection stays a backup rather than the feature that ends your session. The overload protection article covers how the term reads on a listing.

Planning total load before a Texas storm season

Before a winter storm or a summer heat wave, the Texas Division of Emergency Management and Texas Ready pages carry the preparedness guidance for the season. On the equipment side, total load is a shopping step: compare the AC output figures on the listings you are considering, decide which devices will run at once, and narrow the models with the guides below.

In a close neighborhood, a power station is one option to compare with a fuel generator; the backup power guide and the power station versus gas generator comparison both cover that choice without promising a result.

Questions for the maker and an electrician

The listing states the terms; the maker's manual and support state how the model behaves. Ask the maker how the overload protection works on the model and what the manual says about running several AC outlets at once. If your devices connect to a home's wiring or a well pump, a licensed electrician and the local permit office decide that setup.

The station's label and its manual also state the watt rating the inverter provides; that is the figure to compare against your added load.

What to pick for your situation

Questions

Is a battery's watt-hour capacity the same as its output watts?

No. Watt-hours measure stored energy; watts measure the rate of output. A station can hold a large capacity yet have a smaller AC output figure, so compare each figure to its own job. The EIA's measuring electricity page explains watts as the unit of power.

How do I know my total load on a listing's terms?

Add the running watts from each device's rating label and compare the total to the AC output figure on the listing. The maker and a licensed electrician decide whether the devices you own fit the station.

What happens if the total goes over the output figure?

The listing may name overload protection as a feature that cuts or limits AC output when demand exceeds the inverter rating. The maker's manual explains what the model does in that situation.

Why do some listings show a surge figure?

A surge or peak figure is the brief higher rate allowed when devices with motors or compressors start. The continuous AC output figure is the one to compare your added running watts against, and the maker's page states both.

Should I plan for winter storms or summer heat when buying?

Prepare with the Texas Division of Emergency Management and Texas Ready pages, then compare the AC output figures of the stations you are considering. The guides below list models by capacity tier and by the features named on their listings.