Also known as battery juice, (or Milliamp Hours if you’re being technical about it)
Time and again, customers tell us that their number one smartphone priority is battery life. That’s a huge challenge for us. Phones are becoming more and more powerful, and people want to do ever more complex things with them, but at the same time, they want miniaturisation and smaller form factors.
Batteries are measured in mAh (milliAmp hours). A 2000 mAh battery can supply 200 milliAmps over 10 hours and it’s my job at Sony to balance all the competing requirements by designing and creating the batteries that power our smartphones.
The key challenge when it comes to battery design comes down to the nature of the battery. Essentially, all batteries use a chemical reaction to create the current and you can’t get away from the fact that more chemicals = a longer reaction. To put it more simply, physically bigger batteries will always provide longer battery life if compared like-for-like with a smaller battery of the same type.
There are however a lot of other complexities that affect battery life (within the “size constraint” issue). First up is the type of battery. Different battery types, work better in different scenarios – even those that have seemingly similar power ratings so, for example, a typical Alkaline AA battery that you could buy on the street will probably have a rating of around 2500 mAh – that sounds a lot but if you were to power a high-drain device like a smartphone with one, it would last for minutes because Alkaline batteries can’t keep up with the amount of current that is needed.
We use Lithium Ion batteries in our smartphones because they have a number of characteristics that suit smartphone use well. They have a great power to size ratio so you can make a powerful battery in a small design, they’re also lightweight and they have a long shelf life (both in terms of holding their power and in terms of being able to recharge lots of times).
When it comes to testing battery life things get even more complicated. We have our own testing regime that runs through a lot of common use-cases (e.g. x minutes spent browsing the internet, x minutes spent calling, x minutes spent messaging etc…) but many of our operator partners use slight variations of software that changes the smartphone’s battery consumption, and so requires a different testing regime.
It’s amazing what factors can affect how quickly a phone drains battery. Some of the details can seem quite insignificant but have a noticeable effect. For example, different shades of the same colours when displayed on the screen can use different amounts of battery in the process. A lot of this is down to how the software works and so we have to work closely with the software teams to understand how people are using the devices and to optimise for the more common uses.
It’s an exciting space to work in because battery life is so important to all smartphone users, and we have such a good offering on our Xperia devices. Our newest device, Xperia X, delivers up to two days battery life1 and also benefits from Qnovo’s Adaptive Charging technology2, which increases the battery’s life span up to twice as long.
It’s only when we’ve done enough of these tests and optimizations that we can even consider making the big claims around batteries that we do and that’s ultimately the aim of my team. It’s less about trying to achieve a high mAh and more about giving the user the best experience of their smartphone for as long as possible. Despite the demands placed on batteries by ever-more-complex software and hardware it’s our job to keep the juice flowing.