Portable Power Stations: The Specs That Decide

A solar generator is a portable power station with a solar input. It generates nothing. It is a battery, an inverter and a charge controller in one box, and everything it delivers was generated somewhere else and stored.

That matters here for one reason: the two phrases name the same product, so a guide that treats them as different categories is describing marketing rather than hardware. This page covers both.

If you are trying to work out whether a power station is even the right answer for your situation, as against a transfer switch or a permanently installed system, start at choosing your backup power type. This page assumes you have decided.

The four numbers, and one of them is usually missing

Reviews of these units compare capacity, weight and how many outlets they have. Two of those matter. What actually decides whether the thing works for you is a shorter list, and the last item on it is the one that gets left out of the specification table.

1. Cell chemistry, which decides the working life

This is the first specification to find and it is usually printed.

LiFePO4 units are commonly rated around 3,000 to 4,000 cycles to 80% of original capacity. The NMC packs that dominated this category until recently were often rated 500 to 800. That is roughly five times the working life, and the price gap is nowhere near five times.

A unit cycled once a day reaches 500 cycles in under two years. The same use on a LiFePO4 pack is most of a decade. If a listing does not state the chemistry, that is itself informative: the makers using LiFePO4 say so, because it is the better answer and they know it.

Why the ranges vary, and why they differ from the house battery pages. “LiFePO4” names the cathode chemistry, not a grade. Within it, cycle life depends on cell quality and manufacturing consistency, and on how hard the pack is worked: depth of discharge, charge and discharge rate, and temperature all move the number, sometimes by thousands of cycles. That is why house batteries are commonly quoted at 3,000 to 6,000 cycles while power stations sit nearer 3,000 to 4,000.

Depth of discharge alone can swing it several times over, and one manufacturer publishes the whole curve. The same cells are rated 4,000 cycles at 100% depth of discharge, 6,000 at 80%, and 15,000 at 60%. The batteries guide works out what that means for total energy delivered, and the answer is not proportional.

So a cycle life figure means nothing without the depth of discharge and the endpoint it was measured at, and a bare “3,500+ cycles” on a listing is close to unusable for comparison. It is not that the number is wrong. It is that you cannot tell which of those three rows it is.

The trade is weight and cold behavior. LiFePO4 is heavier for the same energy, and like any lithium chemistry it must not be charged below freezing unless the unit heats the cells first. The same rule governs house batteries, and the reasoning is on LiFePO4 against AGM.

2. Usable watt-hours, not the number on the box

The rated capacity is the cell capacity. What reaches your appliances is less, and for two reasons. The battery management system holds capacity back to protect the cells, and the inverter takes a further 10 to 15% converting DC to AC. Most write-ups count only the second.

Both together are measurable. Worked against BLUETTI’s own published runtimes, three of their units land at 75 to 78% of the number on the box across loads from 600 W to 1,800 W. So plan on about three quarters: a 1,000 Wh unit delivers closer to 750 Wh at the outlets. That is not a defect and it is not dishonest, it is simply what the number means. It matters when you have sized your loads to the rated figure and find yourself short on the second evening.

On a small unit running a very small load it is worse again, because the electronics draw a constant amount whether or not anything useful is plugged in.

Work the loads out first. The appliance power budget turns a list of devices into a daily watt-hour figure, and the outage runtime calculator answers how long a given unit carries a given load.

3. Continuous watts against the surge you actually need

Two numbers describe the inverter. Continuous watts is what it will supply indefinitely. Surge, sometimes called peak, is what it will supply for a moment.

The surge figure decides whether motors start. A fridge compressor, a pump, a power tool or a compressor draws several times its running current for the instant it breaks away. A unit rated 1,800W continuous will run a 700W fridge without noticing, and may still fail to start it if the compressor asks for 2,500W for half a second.

This is the same problem that decides whether a generator can start a well pump. On power stations the surge rating is usually published, which makes this the easier half of the question. What is rarely published is what your appliance needs, so the number to hunt is on the appliance rather than on the power station.

4. The solar input voltage window, which is the one they leave out

Here is the specification that decides whether the “solar” part of a solar generator works, and it is frequently absent from the table.

Every unit has a built-in charge controller with an input voltage window, usually quoted as an open-circuit voltage, or Voc, range. A common one is 12V to 60V.

That window has a floor and a ceiling and both bite:

• Below the floor, the controller never starts. A single small panel on a dull day can sit there producing nothing.
• Above the ceiling, you are past what the input is rated for. Panels in series add their voltages, so this is easy to do by accident.

Work an example. A 100W panel typically has a Voc around 22V. Two in series is 44V, comfortably inside a 60V window. Three in series is 66V, which is outside it. Meanwhile a single 400W residential panel often has a Voc around 45 to 49V, which fits alone and cannot be paired in series at all.

And Voc rises as temperature falls. The figure on the label is measured at 25°C, and on a cold bright morning a panel produces meaningfully more than its rating. An array sized to sit just inside the ceiling in summer can step outside it in winter. That is the same trap covered in why a 48V part is not for a 48V bank, and it applies here with the same arithmetic.

Check the window before buying panels, not after. If the specification table does not carry it, it is usually in the manual, and if it is not there either then that is a question for the manufacturer, not a detail to guess at. How a charge controller decides what to draw is covered on the charge controllers page.

The deciding number is rarely on the page you are shopping from

This keeps happening across product classes, and it is worth knowing as a habit rather than as a complaint.

The specification that actually decides a purchase is usually published somewhere. What it is not is on the listing, in the marketing bullets, or in the comparison table. It is in the manual, in a datasheet PDF, or on a specification tab you have to go looking for.

On generators it is total harmonic distortion, which decides whether an inverter charger will accept the power at all. On inverters it is how long the surge is held, where the same manufacturer can give different answers in different places. Here it is the solar input voltage window, which decides whether your panels work, on a product often sold as a solar generator.

The common thread is that these only matter when the power source is limited or the installation is unusual, which is the off-grid case and not the case the marketing is written for. So assume the number exists and keep looking. Check the manual before the product page, and ask the manufacturer directly if it is not in either. The absence of a figure from a listing says nothing about the product; it says the listing was written for somebody else.

Three units whose figures have been read at the manufacturer

Disclosure: This page contains affiliate links. If you buy through them I may earn a commission, at no extra cost to you. This never affects which products I recommend or what I say about them.

Everything in the table below comes from BLUETTI’s own specification tabs and user manuals, read on 2026-09-18. They are one manufacturer’s current portable line, and that is a deliberately small set for the same reason the inverters guide compares within one maker: being checkable is not the same as being best. A unit nobody publishes a surge figure for cannot be recommended here, however good it is.

Two things in that table are worth saying out loud. Capacity and output do not rise together: the largest unit has a lower continuous rating than the middle one, because its extra weight went into cells rather than inverter. And the solar window is the same 12V to 60V on all three, which is the specification this page argues decides whether your panels work at all, so the arithmetic is identical across the line.

Do that arithmetic with your own panel’s open circuit voltage rather than its wattage, because wattage does not tell you the voltage. Two of the 100 W panels on the solar panels guide reach 45.58V in series and fit; a third takes the string to 68.37V and does not. A 100 W panel from somewhere else with a different Voc gives a different answer. Panels also make more voltage when they are cold, so check the string against the coldest morning, not the datasheet figure.

Their own pages do not agree on what surge means

This is the page’s argument, demonstrated inside one product line.

The Elite 100 V2 lists Surge Power and Lifting Power as separate rows with different numbers. The Elite 300 gives both labels the same number. The Elite 200 V2 lists only Power Lifting and no surge at all. The previous generation AC180 is worse: the same 2,700 W is called Power Lifting Mode on its own product page and Surge in BLUETTI’s comparison table.

Those are not interchangeable. Power Lifting is described by BLUETTI as a mode for pure resistive loads, kettles and heaters and hair dryers, run above the rated output. Starting a motor is a different demand, and it is the one this page’s third specification is about. None of the three manuals carries a surge row, and no page carries a duration, which the inverters guide established is the half that decides whether the motor actually starts.

So compare these units on capacity, continuous output and the solar window, which are stated plainly, and treat the surge row as an open question to put to the manufacturer.

Scope, and what this guide does not do

It names three units, and that is the whole set. These are the units whose figures have been read at the manufacturer, which is why bigger names are absent rather than rejected. The set grows as datasheets are read, the way it did on the batteries guide.

It is about the unit, not the installation. A power station with a plug on it is the one backup arrangement that touches no house wiring, which is most of its appeal. The moment you are thinking about connecting anything to a panel, that is a different question with different rules and it starts at choosing your backup power type.