How to extend the battery life of your smartphone
But, almost as an afterthought, I pulled out a bulky Dell laptop I had sitting around (just visible in the bottom left of the photo above) and plugged it in to charge its internal battery, just to have as many charged-up devices on hand as possible. Of course, the lights did go out in the southern third of Manhattan (including my apartment and CNET's New York offices), and they remain out as of this writing.
Internet access through my cable provider was out, and my 3G hot spot was useless as well. Within a few hours, mobile phone service was also down, so my various laptops were useless for getting online and getting information.
But, there were a handful of "live" mobile phone reception spots where service was available, including one near me in SoHo. Running out there every few hours to check the latest blackout news and make a few phone calls was tough on my phone's battery -- as was its constant search for a usable signal (some great blackout-friendly phone battery life tips are here).
Fortunately, the Dell laptop's battery was fully charged, and at least one of its USB ports was of the sleep-and-charge variety, which allowed me to use it as a power source while the laptop was closed or in sleep mode.
Without ever opening the lid, I kept two iPhones, an iPad, and a few other odds and ends charged between Monday and Wednesday, including several near-complete phone-charging cycles. The impact on the laptop battery was surprisingly minimal, and by the time I decamped for a non-blackout location, the Dell laptop had used less than 20 percent of its battery power. I could have easily kept my devices charged for a week like this with some judicial use.
As an extra precaution, I unplugged the device cables when not in use, to make sure I wasn't drawing phantom power from the laptop, otherwise my phones would have stayed topped-up at the cost of some of my reserve batter power.
Doing this during a blackout with the same primary laptop used for writing, movie-watching, or connecting to a 3G hot spot (if available) is more problematic, especially if you have a fast-draining laptop, such as an ultrabook or MacBook Air. Fortunately, having an extra machine sitting around let me set one up as just a USB charging station, while using the other for regular laptop tasks (which were still severely curtailed by the lack of Internet access).
The takeaway here is clear. If you have an old laptop sitting around or live in a two-or-more laptop household, and a power outage may be imminent, consider keeping one charged up and waiting for use as a USB charging station. Obviously laptops with larger batteries that need to power full-voltage CPUs, big screens, or graphics hardware work better. Or maybe we've finally found a practical use for all the dormant Intel Atom Netbooks gathering dust in closets and desk drawers around the country.