You can never have enough battery power, especially when you're traveling. A handy flashlight and a fancy LCD for management don't hurt either. If you're in the market for an external battery pack, Woot has an especially big one on sale today: a massive 16800mAh portable charger from Gorilla Gadgets. You can pick it up for $39.99 plus Woot's usual $5 shipping, which is $30 off the same product on Amazon.
Let's say your smartphone has a battery capacity of 2400mAh. With this gadget, you can recharge it a full seven times without ever needing to find a wall charger. Bigger and more capacious phones (Galaxy Note, MAXX, any of the large-screen phablets) will get fewer charges, but they also tend to last longer anyway. Depending on the size of your tablet, you could get 2-4 complete recharges out of the portable battery pack. Throw in a handy LCD to show the remaining charge, dual 5-volt USB output (one with two amps for bigger devices), and a handy LED flashlight, and this sucker is incredibly useful. Keep in mind that the bigger the battery, the bigger the size: the dimensions on Woot put it at about the same volume as a small paperback book and 3/4 of a pound. It includes a standard MicroUSB cable, plus adapters for Apple Lighting and 30-pin connectors.
This is Woot's main sale for today, so get on it fast - useful items like this tend to disappear rather quickly from the popular site. The sale will end at midnight Central time, even if there is remaining stock. You can pick up the Gorilla Gadgets charger in black or white.