It's all about power baby. More specifically it's all about when the power runs out, and how bad it shafts you when it does. All assuming of course that you're not a purist who eschews - that's right, eschews! - a little battery action in the wild.
If you bring anything battery operated into the sticks, it's probably going to be a cellphone. After that, we really don't want to speculate about that buzzing noise in your tent. There are a number of battery cases out there for pretty much every cellphone in existence, and PowerSkin makes a bunch of them.
We tested the PowerSkin Spare for iPhone 6 and came away unimpressed. The PowerSkin takes a different approach from most other cases, in that it doesn't offer much in the way of impact protection. It's basically a hard plastic shoe that cover the back and sides of the phone and leaves the front exposed. This isn't necessarily bad, as the PowerSkin adds little weight - just 3oz - and little girth - just a quarter inch depth and a half-inch length. The PowerSkin is color-matched nicely, and it includes a pass-through for charging and syncing, but the headphone port is just big enough for the default Apple connector, which is not very big and could be an issue for other headphones.
Now we get to the meat of the matter: when repowering a dead iPhone you'll only get in the 80 percent charge range, which is to be fair about what you'd expect from a 2200mAh battery. All of this isn't necessarily bad, if you you aren't looking for major protection and just want a slim, attractive and unobtrusive battery case. However, be aware the PowerSkin is priced to compete with battery cases that offer more in all these categories, and that's not so attractive.