They're becoming a must-have accessory.
You've seen them on other sites as well as on SolidSignal.com
... those little external battery packs that charge your phone while you're walking around. They've gone from expensive toy to must-have necessity in a very short period of time. Luckily, prices have come down as well, with most chargers coming in at the sub-$30 range.
The cell phone battery pack isn't really some marvel of modern technology... break one open and you'll usually find a pair of rechargeable AA batteries and just enough circuitry to transform the voltage up to the 5V USB standard. A few of them have enough battery power to provide the 2.1 amps that tablets and some smartphones crave, but that's just a little bit more circuitry and a bigger battery. Nothing special.
I will tell you that as I'm traveling all across the country blogging and making great deals for our Solid Signal customers, my cell phone battery pack is indispensible. Whomever decided that it was ok to have a cell phone last 6-7 hours on a charge obviously never had to depend on one, and rather than look like some addict looking for a fix as he scours walls for open outlets, I coolly and casually plug my phone into the battery pack in my pocket and all of a sudden I have another 6-8 hours of time on my device and that's usually enough to last all day.
I'm a little surprised that these gadgets weren't the hit of the holiday season, but now that we're all back to work perhaps we'll remember what a critical need we have for our cell phones, and if you need your phone as much as I do, you really ought to consider having some sort of battery backup for it.