Majority of people who need a better battery don't know how to usr their phone.
Manufacturers wouldn't distribute a device that had 4 hours of battery life with average use.
People who need better battery life because they are heavy users who prefer to push their phones to the limit should by one or two portable chargers. You sprinted to the finish line.. Now wait patiently for technology to catch up.
I just voted. As thick as the iPhone 4s for 50% more battery life.
This choice is on top with almost 67% of the votes.
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It should be like this. A solid piece of aluminum. Rounded for comfort, and while thin towards the edges thick in the middle.
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Adding that thickness and bigger battery would also make the device heavier. Use a battery pack if you don't mind thickness and heavy devices. I want my phone to be slim and light and my 5s already have great battery performance.