While travelling in NYC, I noticed that my T-Mobile Google Phone G1 would run out of battery after 8 hours. I tried the resolve this by changing the data network to 2G, but it did not affect it at all. Note, I have turned off most services on my phone too — no e-mail sync, no bluetooth, and no wireless. 

The problem appears to be occuring when there is no data/voice cell phone coverage, the G1 uses a LOT of battery power to find a signal. Normally, I never run in the red (<10%) with a good amount of usage on the phone. The only way I was able to extend the battery life was to use the “Airplane Mode” on the phone while in the subway. Unfortunately, this prevents people from calling me while in the subway. But, it doesn’t matter anyway — AT&T coverage is much better in the subway vs. T-Mobile.

As far as devices that extend the G1 battery life, they are far and few between. I have some issues with the G1 — GPS isn’t working all the time (hardly ever works), awkward ergonomics, SLOW CAMERA (4-8 seconds to capture the image), and the browser still needs refinement. It needs multi touch!! The zoom interface is poor, I always end up touching another link on a page I’m looking at rather than the zoom buttons. I’m waiting for Kensington to make a mini battery extender for the G1, otherwise I might be in the market for the iPhone.