When you're spending the day with family you probably haven't seen in a year, nothing is more vital to keeping your sanity than your smartphone. And to ensure it's got enough charge to keep you busy on Twitter instead of actually having to talk to your cousins, the diminutive but clever Plan V charger accepts common 9-Volt batteries for a quick boost.

Smaller than most of the keys in your pocket when folded away and weighing even less, the flexible Plan V opens to reveal a spot to plug in a 9-volt, as well as a microUSB port for connecting it to your smartphone. A full battery can provide an additional four hours of talk time on your phone, which is more than enough time to survive a family dinner.

The creators of the Plan V have opted to go the Kickstarter route to make their invention a reality, and a donation of just $10 secures you a microUSB version with a delivery of sometime in February, assuming the crowdfunding campaign reaches its $30,000 goal. And if it does succeed, the creators will be able to also introduce a Lightning version of the Plan V for iPhones, so iOS users might want to tip off their Android-using friends about the Kickstarter, to help ensure there'll be versions for both camps eventually. [Kickstarter - Plan V via OhGizmo!]