How long does it take to charge a power station with solar panels?

At best, battery Wh divided by solar watts. A 1070 Wh Jackery Explorer 1000 v2 needs at least 5.3 hours of full-rated output from one 200 W panel, or 2.6 hours with 400 W of panels, its maximum solar input. Panels rarely make their full rating all day, so real charging usually takes longer, often more than one day of sun.

How do you calculate solar charging time?

Charging time (hours) = battery Wh / solar watts reaching the station.

The solar watts are the smaller of two numbers: what your panels actually make, and the station's maximum solar input. For the Explorer 1000 v2 with one 200 W panel:

• Battery: 1070 Wh (Jackery's spec page).
• Solar watts: 200 W at best, under the station's 400 W limit.
• Time: 1070 / 200 = about 5.35 hours of full-rated sun.

That is the minimum from empty. Charging from half full takes half as long.

Charging also loses a little energy. Anker says the SOLIX C1000 Gen 2 recharges fully in 1.8 hours from 600 W of solar. That is about 1080 Wh in (600 x 1.8) for a 1024 Wh battery, roughly 5 percent more than the battery holds. The pure division gives 1024 / 600 = 1.7 hours, so the maker's own figure is a little longer, as you would expect.

How long do popular power stations take to charge from solar?

At each station's full rated solar input, from empty, the minimums are:

Each figure is battery Wh / max solar input, from the maker's own spec page. Reaching those times needs enough panels to fill the input: five 200 W panels for the DELTA 3 Plus's 1000 W, for example, and only in strong sun. Two stations with the same battery can differ a lot: the Jackery Explorer 2000 v2 and EcoFlow DELTA 3 Max hold about the same energy, but the Jackery's 400 W input makes its fastest solar charge about an hour longer.

For four stations in our data (the DJI Power 500, 1000 and 2000 and the Jackery Explorer 1500 v2) the maker's spec page did not give a solar input figure we could cite, so we leave them out.

Why does solar charging take longer than the math says?

Because a panel's rating is what it makes in ideal test conditions, and real sun is rarely ideal. Output drops when:

• The sun is low, early and late in the day and in winter.
• Clouds, haze or shade cross the panel. Even partial shade on one corner cuts output.
• The panel is not pointed at the sun. Portable panels propped on the ground drift out of line as the sun moves.
• The panel gets hot. The U.S. Department of Energy notes that higher temperatures lower a solar cell's voltage much more than they raise its current, so a hot panel makes less power.

So treat the table as the floor. Our methods page puts it the same way: solar recharge times assume the full rated input, which panels rarely deliver all day. If your panels make half their rating on average over the hours you have sun, the time doubles.

Does a bigger solar panel charge faster?

Up to the station's limit, yes. One 200 W panel on the Jackery Explorer 1000 v2 gives at most 200 W; two give at most 400 W and halve the minimum time to about 2.6 hours. A third panel adds nothing at full sun, because the station caps solar input at 400 W, though extra panels can help keep the input near the cap on hazy days or late in the afternoon.

Check the station's voltage and connector limits too. Anker, for example, lists the C1000 Gen 2's 600 W solar input at up to 60 V. Panels wired beyond a station's voltage limit can damage it, so follow the maker's manual.

Is solar faster than charging from the wall?

Usually not. The Anker SOLIX C1000 Gen 2 recharges from a wall outlet in 49 minutes at 1600 W in its UltraFast mode, by Anker's own figures, against 1.8 hours from 600 W of solar. BLUETTI lists the AC180 at 0 to 80 percent in 45 minutes on 1440 W of AC input. Solar's advantage is that it works with no grid at all, which is the point in a long outage.

How should you size solar for an outage?

Start with what you use in a day. If your loads need 1466 Wh a day, like the fridge, lights and phone in our 24-hour fridge outage scenario, you need to put back at least that much each day, plus charging losses. Compare that with the energy your panels can make in the hours of good sun you get where you live.

See the stations page for every model's solar input and battery size, and try a station in the runtime calculator to see how long a full charge lasts. Related: can a solar generator run a house, can a power station run a sump pump and what to look for in a portable power station.