Portable solar panels, explained before you spend.

How it works

Sunlight in, electricity out

A solar panel is a grid of photovoltaic cells, each made from thin wafers of silicon treated to create an electric field. When photons from sunlight knock electrons loose in the silicon, current flows. That direct current (DC) feeds straight into a power station or battery through a cable and connector.

Nearly every portable solar panel sold today uses monocrystalline silicon cells, cut from a single crystal ingot. Monocrystalline cells are more efficient per square inch than the older polycrystalline type, which is why modern panels produce more watts in a smaller, lighter package. All eight panels we have reviewed are monocrystalline.

A newer cell design called IBC (interdigitated back contact) moves all the wiring to the back of the cell so the front surface collects more light. The Jackery SolarSaga 200W and EcoFlow 220W Bifacial use IBC cells, which helps them reach stated efficiencies of 24 to 25 percent. For a household buyer, that efficiency number means less physical panel area for the same wattage, which means easier storage and transport.

Panel technology

Bifacial panels: when the back surface earns its keep

A standard panel has an opaque backing. Light hits the front, and anything that bounces off the ground is wasted. A bifacial panel has a transparent back, so reflected light from the surface below reaches a second layer of cells. Two of the eight panels we reviewed are bifacial: the EcoFlow 220W and the Jackery SolarSaga 200W.

The real-world gain depends entirely on what the panel sits above. On a light-colored concrete patio or fresh snow, the back surface can add 12 to 18 percent. On grass, it is closer to 5 to 8 percent. On dark asphalt, the benefit is negligible because almost no light bounces back.

Bifacial panels cost more and weigh more. If your setup surface is concrete, gravel, or a deck that reflects well, the extra cost can pay for itself in faster charging. If your panel will mostly sit on grass or dirt, a standard panel at the same wattage produces almost as much power for less money.

The shade question

Series vs. parallel: how one strip of shade changes everything

Inside a folding solar panel, the individual cells are wired together in one of two ways, and the difference matters enormously if any part of your panel will be in shade.

Series wiring connects cells end to end in a single string. Current flows through every cell in sequence. If one section is shaded, that section acts like a bottleneck and the entire panel's output drops. The Jackery SolarSaga 200W is series-wired. In our review, shading one of its four panels dropped total output by roughly 70 percent because the shaded section throttled the whole string.

Parallel wiring connects cell groups independently, each with its own path to the output. A shaded section loses only its own contribution while the remaining sections continue producing. The BLUETTI PV200 uses parallel wiring. Shading one of its sections reduced output by roughly the proportional area of that section, not the whole panel.

If you set up in full, unobstructed sun, wiring topology makes little difference. If your driveway, patio, or campsite has trees, buildings, or any other source of partial shade, parallel wiring is the better investment. This is the section that can save someone several hundred dollars on the wrong panel.

Matching panel to station

How much panel do you need?

The answer starts with your power station's capacity in watt-hours and works backward. Use 80 percent of the panel's rated watts as your real-world number, then divide.

Two panels vs. one bigger panel: two 100W panels can sometimes outperform one 200W panel because you can angle each independently and shade on one does not affect the other (assuming they connect in parallel to the station). Two panels also give you a backup if one fails. The trade-off is more cable, more setup time, and more to store.