For better or worse Hurricane Sandy will be past us on the east coast in 48 hours. But winter is coming, bringing yet more opportunities for electrical service to be interrupted.

Cell phone towers have backup batteries that can last for some hours or longer, so keeping your cell phone available for emergency calls is a good idea. Here are some tips to maximize the juice in smartphones:

– Turn off your phone’s wifi side (since your cable modem isn’t on, so there’s no sense it letting the phone keep searching for a signal) and Bluetooth services.

– Turn off most of its location services. On an iPhone go to Settings-Privacy-Location Services. You can either turn it off altogether, or leave Location Services on but go in and turn it off for most individual apps – if you have emergency notification apps like Ping4Alerts and CodeRED leave those on to get warnings from your city/state emergency management).

– Adjust the screen illumination to be as dim as possible, and to turn off the screen with the shortest available idle time.

– If you don’t plan to use your laptop for offline work, charge your phone from its battery.

– If you have a car, get a 12V charger for your phone (and gas up the car before the storm!).

– Plan ahead: this 12V storage battery (designed for powering Celestron telescopes) has two 12V jacks plus built-in small and large lights. Also pick up a DC/AC inverter and you can charge your phone plus power some other gear (e.g., recharge a laptop).