Wenger, an original maker of the Swiss Army Knife, has launched a line of solar panels made for outdoor use. The foldable panels come with a built-in rechargeable battery pack and can mate to most any smartphone, tablet, mp3 player, camera, or GPS device sold.

We tested the brand’s 4.5W version on few device-intensive wilderness excursions, including during a two-day period where I served as a race director in Oregon earlier this fall. We were in the wilderness with no available power except solar and relied on the Wenger panel to charge our smartphones for communication and Web updates.

Just like its knives, Wenger’s solar charger is multifunctional — the flexible solar array has four foldable panels, a built-in battery to store power, and a USB cable with standard plugs to connect to devices.

Straps, snaps and bungees on the outside let you drape it over a backpack as you hike or on a seat in a canoe. The panels are durable. The complete kit packs together in an included bag that’s water resistant.

During the race in September, I left the whole kit out in the open and charging with my phone hooked up. During the next 10 hours as I was away, the skies were partly cloudy with scattered showers.

I was nervous to leave my phone and the panel out for that long in the weather. But I was delighted to find my phone not only safe and dry after I returned but also completely charged from the sun. Impressive.

The unit — official name: Wenger Portable Solar Charger Top 4.5W — costs $270. For this price you get a solid wilderness charging station that weighs 1 pound 8 ounces and folds to fit in a small part of a backpack.

The 4.5W is the middle of the line, with a lower and higher power (and price) unit on either side. All the models come with standard charging adapters to fit most all devices you might charge. One caveat: The Wenger units work with most Apple products but do not come with an adapter for the new iPhone 5 or iPad Mini.

All the Wenger solar products come with a battery pack that you can pre-charge at home. On shorter excursions there’s no need to bring the solar panels. The charged battery pack alone can charge my Droid X smartphone nearly two complete times, making it perfect for a day or two of using my phone and a GPS app in the mountains.

All of Wenger’s chargers have a place to attach a small LED light on back. It runs for hours and is more than adequate for serious camp illumination.

At their prices ($180 to $340, depending on model), the Wenger units are more money than many comparable solar products we have tested. But the Wenger units are also more of a “complete thought” on design than others, meaning they are usable right out of the box in an extremely wide variety of charging situations.

Overall, we found our test unit to be a great design with its solar technology, portable battery, durability, and all-in-one storage for packing away and moving through the mountains. It’s worked for us without issue for three months of testing in the wilds. If you’re in need of electricity without a plug, Wenger’s “Swiss Army Solar” is a solid choice.

—Jason Magness is a contributing editor.