Hurricane Sandy has pointedly reminded us of the usefulness of auxiliary chargers for our continually growing collections of portable electronic devices.
So if you are thinking about portable chargers for your devices, there are two specs you should compare.
The first is the capacity -- how much electric charge you can store in the battery -- measured in milliamp hours (mAh). Speaking roughly, 800 to 3000 mAh can charge a smartphone multiple times, and 4000 to 6000 and up can charge multiple devices, including phones and tablets.
The second key spec is the output -- the strength of the flow of the electric current -- measured in Amps (A). Typically, 1.0 Amps is used for charging devices like smartphones, and 2.1 or more is required for charging a larger tablet device, or to charge multiple devices simultaneously.
Some charger manufacturers helpfully name their products with the mAh capacity, to help you trade off the charging performance versus the size/weight and cost. MyCharge goes a step further, by also building in the power cords / adapters needed to use the device, so you don't need to hunt around for the proper cable, or carry anything extra.
For example, the MyCharge Trek 2000 (with 2000 mAh battery) includes a built-in iPhone dock with Apple connector, and a microUSB cable so you can charge a headset or other device -- simultaneously. Plus it includes a built-in USB cable for recharging the MyCharge from a USB wall adapter (in 3 hours) or from a computer (5 hours).
It's also useful to be able to check the battery level of these devices, so the Trek 2000 has a battery check button with 4 LEDs. Plus, it plays a notification tone when connected, disconnected, and fully charged (and you can disable this with a paper clip). The Trek weighs 4 ounces (about the same as a new iPhone), and is available for $54.
For more power, step up to the MyCharge Peak 6000, with a 6000 mAh battery and total output of 3.1 Amps, so it can charge a tablet, one smartphone up to 4 times, or up to 3 devices simultaneously.
The Peak has three built-in charging options -- Apple cable, microUSB cable, and a USB port. And it has two options for recharging the battery -- a USB cable (which takes 13 hours when plugged into a computer), and fold-out AC prongs for fast charging from a wall outlet (in 4 hours).
It also as an even nicer feature for checking the battery -- in addition to 4 LEDs, it also provides voice notification of the battery level and charge complete -- and in your choice of four languages).
The MyCharge devices make a lot of sense to have around as we head into deep winter. In particular, the Peak 6000 packs a lot of power in a relatively small and light package -- at 5 1/3 x 3 x 1 inches and 8.5 ounces. It's available for around $99.
See my Holiday Gadgets 2012 coverage of Portable Accessories for more on chargers and other useful and fun ideas.
Find the MyCharge Trek 2000 and Peak 6000 on Amazon.com