I recently upgraded from my iPhone 3GS to an iPhone 4.

Usually, I’m the first of all my friends and relatives to get the new tech, but this was a work phone … and it took some time. However, the wait only sharpened the anticipation – and one of the things I was looking forward to was better battery life.

With my 3GS, I got maybe a day and a half of battery life – less if I used my phone a lot. I was hoping for much better from the iPhone 4. It was a huge disappointment, therefore, when my new iPhone 4 seemed to lose all battery charge daily.

The loss of charge was so bad I suspected getting a lemon. Even overnight, when I put my phone in airplane mode, I’d lose about 10% or more. The 3GS had never lost more than 1 or 2% of battery charge overnight. I seriously had to recharge my iPhone4 daily. So I did some investigation.

It turns out that if you set up your new iPhone 4 from a backup of your old iPhone, some old settings which relate to battery life get installed on your new iPhone … and your battery use is totally de-optimized.

The solution: set up your iPhone 4 as an entirely new phone.

Here’s how:

  1. Connect your iPhone to your computer
  2. When iTunes opens and your iPhone is active in the source list, select the Summary tab at the top
  3. Click the Restore button
    (this will delete everything off of your phone, so be sure you’ve done a recent sync and no important information is only on your phone

  4. After your phone is restored, set it up as a new phone in iTunes
  5. Re-sync all your data, email, songs, apps, etc. over to your new phone
  6. Enjoy your new much longer lasting battery life!

After doing this, my iPhone 4 battery life is MUCH longer. Currently, I’m at about 2 days with reasonable usage … and my battery is still at 34%.

Now that’s what I expected from my new iPhone!