A portable laptop battery that can be attached to just about any laptop and recharge its internal battery or allow it to run longer seems like a very good idea indeed. Propota's Portable Laptop Battery does just that. "This handy product charges from your laptop's AC adapter and stores an impressive 6000 mAh of power for when you need it. The Portable Laptop Battery comes with a selection of input and output tips to cater for most 16V and 19V laptops." cited the tech site DigitalMedia from the producers home page. "When your laptop is next running low, insert the battery's output cable and tip into the laptop charging port, and recharge your laptop for prolonged use."

Using this external battery is really simple: one should just insert the battery's cable into to the laptop's charging port, or for USB powered-devices (mp3-players, iPods, digital cameras, cell phones) the battery has a special USB compatible port that allows recharging on the fly.

Unfortunately, the Portable Laptop Battery doesn't support just every type of cell phone on the market (for example Nokia N95 is not supported) and neither are Mac laptops supported. On the bright side, the number of supported devices is much bigger that the number of unsupported ones. The output of the battery (6000 mAh) should be sufficient for several emergency laptop recharges and at just 600 grams in weight it is easy to transport and store (it is packed in a slim form factor, only 15mm in height). In order to support a larger number of laptops, several interchangeable recharging tips are provided (7 input connector tips and 8 output connect tips). As the Portable Laptop Battery comes only with one output cable, recharging multiple devices at the same time is not possible.

Proporta (designer and manufacturer of accessories of mobile computing) sells the Portable Laptop Battery for $199 and, considering its features, the price seems right.