Eton BoostSolar

Eton BoostSolar (Eton photo)

What it is: A rugged, water-resistant lithium battery with a built-in solar panel for power on the go. It has a micro-USB input that allows you to charge it before hitting the road. The 2.1A USB output is powerful enough to charge a tablet. When you're out and about, the 6-inch square solar panel allows the sun to give the battery a boost. A fully charged BoostSolar can recharge most smartphones twice and boost the power of a tablet. LED lights indicate both when the battery is charging and how much of a charge is left.

The good: This is a great backup battery to carry on a hike, a boat or a beach. It's rugged design makes it ideal for outdoor activities, and it's easy to hang on a backpack by attaching a carabiner to one of the four fastener loops so the panel is angled toward the sun. The green LED light indicators blink when the battery is charging so you know the panel is at the best angle. Another plus is that BoostSolar weighs less than 12 ounces, lighter than many solar panels and backup batteries.

The bad: The BoostSolar doesn't come with a carabiner. Also, a more efficient solar panel would be nice but probably would increase the size of the device. The solar panel takes 30 hours in direct sun to fully charge the battery, so its use is more to boost the battery than power it up completely.

Cost: $129.99 list, but you can find sales $30 cheaper

Available from: etoncorp.com, rei.com and amazon.com.