Dec 5, 2011

Improving battery life for Apple devices

There is an ongoing discussion on the Internet about troubles with iPhone 4S battery and iOS 5. Many users got decreased battery life with iOS 5. While it is definitely a problem in the firmware, there are ways that can help you increase battery life of any Apple device. I am talking Apple here because I used that for every Apple device I owned. Apple designs batteries themselves and all batteries I had, were made by a single manufacturer. So other devices may need a different way to extend battery life.

When I got a new iPhone 4S, it came with iOS 5.0. I upgraded to iOS 5.0.1. The phone did not survie a day of charge. Now it survives 3 days with using e-mail, twitter, facebook + location services. How did I do that?

The key is battery training. Apple batteries are complex electronic, mechanical and chemical structures. They are not those primitive AA batteries. Apple batteries have electronic brains and multiple cells that must work equally well to give you the best quality. In order to serve at full capacity, those cells need to come to a certain internal structure and the chip must learn the state of each cell to give accurate reading to the rest of the system. To do all that, batteries need to be trained immediately after purchase. It is important do that immediately after purchase because that's the best you can do: to train a new battery. If the battery is not trained but you use it, it is like eating a half-made food: you can do that but you cannot fully enjoy it. You still can train the battery later but it will be more difficult to achieve its full power.

Have a look at battery reading I took for my new MacBook Pro in the middle of training:

Design capacity of the battery is 6900 mAh. Current capacity is large, than the design capacity. This means longer battery life.

How accurate is this data? Pretty accurate. It is obtained from the chip inside the battery, which is known to be accurate.

So, how do you train your battery? It is easy.

You need to fully discharge and fully charge your battery while using your device in a normal way. Those three words in bold are important. Fully discharge means that your device must turn itself off. Do not wait, plugin in the power adapter. Now you can continue using the device but you may not disconnect the power source. You must come to a full charge and wait about half an hour on the wall power (100% that battery indicator shows does not mean it is really finished charging). Next unplug and go on using battery. You can sleep the device any time. Just do not plug it back to the power adapter. Use the battery until it discharges. And so on. The minimum amount of cycles is 3. I would do 5-6.

Is that dangerous? How does it count to battery load cycles? Normally batteries have about 1000 load cycles until they start to degrade the quality. Only full discharge counts as a cycle. My battery came with the cycle value of 2, which I believe is a factory setting for a quality tested battery. So I made three cycles so far. 997 to go until the quality start degrade. But since I usually do not discharge lower than 7%, it is a long way to go. The battery in my older (46 months) MacBook Pro can live up to 4.5 hours with a low display brightness and wi-fi off. This is a lot. Many say their batteries live less than an hour.

So, if you want your batteries live longer, train them after buying. It helps.

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