That's a good idea.
Heh, I can visualize me going through the airport with my own security escort :P

What is your country?

Panasonic probably wouldn't lie, but you have no guarantee that the cells have been made by them. The ones you can find locally are probably Chinese fakes with "Panasonic" printed on them, especially if they're cheap. Genuine 3.1Ah 18650 are quite expensive; I've had a look, and I can't find them for less than 12 euro each shipped from European sellers. They are cheaper from Hong Kong (about €8 each), but the fake risk is higher.

2.9Ah Panasonics are considerably less expensive (€8 locally), which would make them a more sensible buy, though still not cheap.

As for 3.8Ah ones, the fact that none of the places I know returns anything other than Chinese brand names (the various WhateverFires) when searching for them says a lot. I'm quite sure no 3.8Ah 18650 cell actually exists on the consumer market, and I'll bet a small amount of money any you manage to buy will give you a lot less capacity than stated, whether it has "Panasonic" written on its side or not.

Heh heh, I even found "4200 mAh" Ultrafires. Anyone who believes that deserves to get suckered.

Yeah, but it'd be a lot more expensive. This mod cost me a grand total of $10 and the phone already lasts a very long time; I just don't have the motivation to spend three times as much money to increase runtimes another 50%.


Runtime report: yesterday I spent about an hour browsing the Internet on 3G, along with the normal non-Internet phone usage. The battery gauge had gone down by exactly one notch from full by the time I went to bed.