Here comes another item I purchased on a whim trying to fill a need. There are a lot of so-called “extended” batteries out there for the iPhone 3G. I was running into issues with my iPhone’s battery being almost dead after only a few hours of heavy use. I decided to research this for use on one of my vacations, since that seems to be the time when you are away from consistent power the most.

My search ended at the Kensington Mini Battery Extender and Charger for iPhone and iPod. This product retails at around $50, but can be found on amazon.com for around $35. It is a very compact, lightweight battery that can be plugged into the dock port on an iPhone or iPod for some extra juice.

There are other batteries on the market, namely the Richard Solo 1800, which gets consistently high ratings. But my problem with that battery is the cost (typically double the price of this one) and the fact that it’s so bulky on the phone. This battery can be attached to your iPhone and you can still talk on it without looking totally foolish. That’s a good feature in my opinion.

The manufacturer of the product, Kensington, claims that this device extends play time up to 30 hours of music or 6 hours of video (on iPod nano 3G) or 3 hours of talk (on iPhone). I never really have scientifically tested these claims, as my purpose for buying this wasn’t to extend my talk time on my iPhone, it was more to be able to keep using it as an internet browsing tablet for long after the regular battery dies, and for that this accomplishes the task well. The Kensington battery charged my iPhone 3G from nearly dead to 70% charge within a short amount of time. That’s a decent amount of extra juice to work with, and totally worth the money to have an emergency battery such as this around.

The packaging is sparse, but includes a retractable USB charging cable (it uses the standard “mini” USB connection) and can be charged off any standard USB port. It also includes a cover for the battery connector, which doubles as a sort of stand you can use to keep your iPhone or iPod Touch standing up to watch movies. I have yet to bother trying this, but it’s a neat little touch.

Overall, this is the best battery for the iPhone 3G I could find that is also portable and cheap. I’ve been using mine for a few months now, and I’d highly recommend it if you’re looking for a spare emergency battery solution that isn’t gigantic and has a decent amount of juice to recharge your iPhone with.