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How Can I get extra battery power from my mobile phone if it shows the battery is nearly empty?
by holding your phone keypad down, all of the power in the battery will fall into the electronics before your phone turns off. also, when charging your phone have it sitting below the power outlet as the electric will fall into your phone quicker.
really though, just put your phone on silent and, if your phone lets you, close all of the running applications and disconnect from the internet.
Mugen Power extended battery for T-mobile MyTouch 3G Slide