Few non-Apple products generate as much short-term buzz as Better Energy Systems' Solio did at the Macworld Expo in San Francisco last January. The product is a solar powered charger for all kinds of electronic devices. At the show, we interviewed the Solio's inventor, and Better Energy's CEO, Christopher Hornor. Since then the biggest development is a drop in price. Solio now costs US$99.99.

Buzz, however, does not always a good product make. We've spent a few weeks with Solio, traveling with it as far afield as southern Chile, and we're happy to say that the buzz is justified. Better Energy has created an excellent gadget.

The device is simple in concept: the sleek casing holds an external battery that can recharge itself either from the sun or via an included AC adapter. If you buy the right cables, you can use that battery to charge all different kinds of devices, including iPods, cell phones, digital cameras, PDAs, and Gameboys. For some devices the company does not make a specific adapter, but one of their dongles allows you to charge any device for which you use a 12V car's cigarette lighter. Solio was not designed to charge laptops (that would require a bigger battery, and therefore a heavier product), but the company tells us a "Solio for laptops" might be in the works.

To charge the Solio, either prop it up in a sunny place, or plug it in to a wall socket. Charging the device from the sun takes a while: about 10 hours of direct sunlight, though the time can vary widely depending on the intensity of the light and how perfectly perpendicular you keep the panels to the sunlight. The summer sun in Santiago, Chile worked nicely: Solio charged about halfway in four hours one morning. But you'll want to find reliably direct sunlight to make it work. We sent Solio out, strapped to the outside of a backpack while hiking in intense sun for over eight hours. Because it wasn't always aimed at the sun, Solio hardly charged at all.

If the Solio is in direct sunlight and properly aligned, it charges pretty swiftly. Otherwise, it takes prohibitively long.

The good news is that you don't need to charge Solio all the way for it to be useful. The amount of device charge you'll get out of Solio depends on what you want to charge, but we got over three hours of charging time using it for an iPod and Motorola phone. If you grab a couple hours of good sunlight here and there when you get the chance, you should be able to maintain enough charge to use Solio as an emergency power supply for just about any device you travel with. Or, consider this metric: one hour of good sunlight equals about one hour of iPod listening time.

Better yet, the Solio is extremely rugged. While attached to the outside of that backpack, it got dropped, bumped, and scratched, and it still looks good, feels good, and works properly. In a moment of especial thoughtlessness we tossed it onto a sand beach, and it has never even grated when opened or closed.

While we can recommend the product as is, Solio still has room for improvement. Our biggest gripe is that Solio suffers either from some user feedback issues or some minor bugs. It isn't always obvious after you plug in a device that it starts to charge. By tapping the button on the Solio after an iPod or phone is plugged in, though, we got good results.

We had some minor mechanical quibbles as well. It would be nice if the back of the Solio were made of a non-slip material to make it easier to prop up in various ways for solar charging. Solio's solar panel petals also ought to have grommets to make it easier to hang or strap on to various objects. The rubber port cover--which is not all that useful and should probably just be eliminated--did not stay plugged in.

The Solio's port cover is one of the few tacky aspects of an otherwise elegant product.

Solio comes with an iPod cable, but ideally one could specify at point of sale which adapters he wants included. And while Better Energy makes many adapters for many different devices, you should make sure before you buy that your devices are supported. Tips for phones cost US$7.99; PDA and Gameboy adapters run $9.99; the 12V car charger adapter is $16.99.

The extremely picky may be excused for waiting for a new iteration of Solio to see if some of these issues get resolved, but for the road warrior weary with power outlet-searching, this is a killer product. It's one of those rare products that raises your expectations: Solio actually lets you do things you couldn't do before.

Solio