What size portable power station do you actually need?

Almost every power station is sold on one number, and it’s the wrong one to read alone. Capacity is printed large because it sounds like size. It isn’t. It’s duration.

The number that decides whether a device works at all is somewhere further down the spec sheet, and on a couple of the units below it’s smaller than the badge on the front would lead you to expect.

What’s the difference between watt-hours and watts on a power station?

Watt-hours are the tank; watts are the tap. One tells you how much energy is stored, the other how fast it can come out.

They move independently, and two real products show how far apart they can get. BioLite’s BaseCharge 1500 is 1521 Wh with a 1200 W continuous AC output. Goal Zero’s Yeti 1500X is 1516 Wh with 2000 W continuous. Five watt-hours apart in the tank. Eight hundred watts apart at the tap.

Run a 1400 W hair dryer and one of those two is a brick. Run a 60 W laptop and they’re near enough interchangeable. Nothing about the headline capacity tells you which situation you’re in.

How many watt-hours do you actually need?

Multiply each device’s watts by the hours you’ll run it, add them up, and that sum is your watt-hour floor. A 60 W laptop for 5 hours is 300 Wh. A 45 W fridge that cycles roughly half the time over 24 hours is about 540 Wh. Together, 840 Wh before anything else is plugged in.

Then add losses, because the battery’s stored energy is DC and your kettle is AC, and the inverter in between takes a cut.

Jackery is the only portable power station maker here that publishes a figure for that cut. Its European help center gives the formula as “Working time = Explorer’s Watt-Hours * 0.85 / operating power of your device”, worked through as “500Wh*0.85/60w = Roughly 7 hours of working time.” The same 0.85 appears in Jackery’s US material, applied to a laptop on the Explorer 1000 v2.

So: 840 Wh ÷ 0.85 is roughly 990 Wh of battery. A 1000 Wh station covers that day with nothing spare.

Do the published runtimes match the published capacity?

No, and the gap isn’t constant — which is the whole problem with a flat efficiency factor.

Take Jackery’s own runtime tables for the Explorer 1000 v2, a 1070 Wh unit, and multiply each listed load by its listed hours:

• 900 W electric kettle, 1.0 hour → 900 Wh delivered, 84 percent of the battery
• 200 W portable stove, 4.1 hours → 820 Wh, 77 percent
• 50 W camping lantern, 13.5 hours → 675 Wh, 63 percent
• 10 W string lights, 35.1 hours → 351 Wh, 33 percent

Jackery’s own formula predicts 18.2 hours for that 50 W lantern. Jackery’s own table says 13.5. Both numbers are published by Jackery; they don’t reconcile.

The same arithmetic on EcoFlow’s DELTA 2 — a 1024 Wh unit — gives 880 Wh implied for a 110 W TV over 8 hours, and 580 Wh implied for a 10 W light over 58 hours, from EcoFlow’s own list. Eighty-six percent at the top, 57 percent at the bottom.

The pattern is the same in both: the lighter the load, the worse the conversion looks, because the inverter’s own idle draw is a fixed cost spread over a smaller output. Neither company explains this on the page.

Victron Energy does publish the curve, for standalone inverters rather than power stations. Its technical note gives measured efficiency for a Phoenix 24/3000 as 93.9 percent at 800 W, 91.5 percent at 1600 W and 86.5 percent at 3000 W. Efficiency falls as you approach the rating. Use 0.85 as a planning number if you like — Jackery does — but treat it as a rough middle, not a constant.

How much continuous output do you need?

Enough for everything running at once, with the biggest starting load on top. That second half is where sizing goes wrong.

Model	Capacity as published	Continuous	Surge	Longest and shortest job the maker lists
EcoFlow RIVER 2	256 Wh	300 W	not published	10 W light, 4 h; 50 W electric blanket, 0.8 h
Goal Zero Yeti 500	499.2 Wh (25.6 V, 20 Ah)	500 W	1000 W	4.5 W lamp, 94 h; 80 W TV, 5.3 h
EcoFlow DELTA 2	1024 Wh	1800 W	2700 W	10 W light, 58 h; 1150 W electric grill, 0.7 h
Jackery Explorer 1000 v2	1070 Wh	1500 W	3000 W	10 W string lights, 35.1 h; 900 W kettle, 1.0 h
BioLite BaseCharge 1500	1521 Wh (21.6 V, 70.4 Ah)	1200 W	2400 W	Wi-Fi router, 136 h; microwave, 62 min
Goal Zero Yeti 1500X	1516 Wh (10.8 V, 140.4 Ah)	2000 W	3500 W	4.5 W lamp, 337 h; 1000 W microwave, 2 h
Jackery Explorer 2000 Plus	2042.8 Wh (45.6 Ah / 44.8 V)	3000 W	6000 W	not published

Every capacity above is the nominal figure. None of these makers publishes a usable capacity separately from it, and none publishes a list of what its station will not run — the appliance lists are advertisements, not limits.

Read the table sideways rather than down. The BaseCharge 1500 and the Yeti 1500X sit five watt-hours apart and 800 W apart. The DELTA 2 holds 46 Wh less than the Explorer 1000 v2 and delivers 300 W more. Tank and tap are separate purchases that happen to arrive in the same box.

Jackery states the sizing rule directly in its own guidance: work out “the total running wattage and the highest starting wattage” and add them. A fridge drawing 120 W running may pull several times that for the instant its compressor starts, and that instant is what trips an undersized inverter.

What does a surge rating actually promise?

A wattage, and — from every power station maker checked here — no duration to go with it.

Jackery publishes 3000 W surge peak for the Explorer 1000 v2. Goal Zero publishes 3500 W surge for the Yeti 1500X. Neither says for how long, or how often, or at what temperature.

Compare that with the makers who sell the components rather than the box. Battle Born publishes “200 Amps Surge for 30 Seconds” on its 100 Ah datasheet, plus a half-second allowance above that. Renogy publishes 2000 W continuous, 4000 W peak and “Nominal Efficiency > 90%” for one of its inverters. Samlex America publishes 1500 W continuous and 3000 W surge for the PST-1500-12, with no efficiency figure on that page.

Victron goes further and refuses to give continuous power as a single number at all. Its Phoenix Inverter Smart datasheet lists the 3000 VA model as 2400 W at 25 °C, 2200 W at 40 °C and 6000 W peak, measured on a “non-linear load, crest factor 3:1.” Its technical note explains why: “in our datasheets inverters, and the inverter function of Multis and Quattros, are rated at 25ºC,” derating to 90 percent of that at 40 °C and 75 percent at 60 °C. A hot station in a sealed truck box is not the station on the spec sheet. If the inverter’s waveform matters to your load as well as its wattage, that’s a separate question we take up in pure vs modified sine wave.

Is the published capacity the number to trust?

It’s the right unit, but check which region’s page you’re reading, and never size off amp-hours alone.

Amp-hours are meaningless without a voltage, and Goal Zero demonstrates this inside its own catalog. The Yeti 1500X is 1516 Wh at 10.8 V, or 140.4 Ah. The newer Yeti 1000 is 998.4 Wh at 51.2 V, or 19.5 Ah. Seven times the amp-hours, one and a half times the energy. Goal Zero prints a third figure on the same pages — a “single cell equivalent” of 421 Ah at 3.6 V for the 1500X — which is the same energy again in a third costume. Battle Born’s 100 Ah datasheet, meanwhile, publishes no watt-hour figure anywhere. Convert before comparing.

Then there’s the regional split. EcoFlow’s US page and its own DELTA 2 manual both cap X-Boost at 2200 W. EcoFlow’s UK page for the same model advertises “up to 2400W” with X-Boost. Same product, same company, two published ceilings — so the number you plan around should come from the manual for the unit you’re actually buying, not the marketing page that ranked highest.

X-Boost itself is worth understanding rather than trusting. EcoFlow describes it as “intelligent voltage control that marginally reduces voltage, allowing you to power devices with a lower-rated inverter”, covering appliances that need “up to 2x your Portable Power Station’s AC output wattage to start.” EcoFlow also states it doesn’t work while the station is charging. Deliberately running an appliance below its design voltage is a reasonable trick for a resistive heater and a poor one for a motor — and the cell chemistry underneath, which we cover in LiFePO4 vs lithium-ion, changes none of that.

The short version

Size the battery in watt-hours and the outlet in watts, and treat them as two separate checks that both have to pass. Multiply each device’s wattage by its hours, sum them, then divide by about 0.85 for conversion losses — Jackery’s own published factor, though Jackery’s own runtime tables imply anywhere from 33 to 84 percent depending on load, so leave margin. Confirm the continuous rating covers everything running at once, and that the surge rating covers the largest motor starting, remembering that no power station maker here says how long a surge may last. And if the plan is to top the thing up from the sun rather than a wall socket, the panel is its own calculation, in solar panel sizing.