Those who are familiar with portable video players, like the types on cell phones and iPods, know how quickly battery power is eaten up during simple playback. Princeton is doing its part to increase your mobile video experience with the unveiling of the PMP-BP18 emergency battery back.

The two-ounce unit is designed for compactness at 3.7 inches tall and 2.2 inches wide. Simply hook up your portable device into it, and it will provide the extra power you need to watch your videos on-the-go. Supposedly, the PMP-BP18 can fully charge a typical Japanese cell twice before needing a recharge of its own.

As you can see, the adjustable tilting dock allows you to place your iPod or cell on the device itself, so it won’t slide off your lap during viewing. What you can’t see is that it is able to charge via USB. Not bad.

The Princeton PMP-BP18 should be available soon, for a US price of about 42 dollars.