The apps that drain your smartphone battery

Every time an app notifies you of new social activity it drains the battery.

Messaging apps such as WhatsApp and Facebook Messenger are some of the biggest smartphone battery and data hogs because they frequently connect to the internet to check for updates.

These are among the least efficient apps when judged on a credential known as "signalling", according to a new report.

Signalling is when an app activates, or "wakes", a device to send and receive data from the internet. It sets up a radio channel for a smartphone to communicate with the mobile network, using up battery and data. The more often a connection is opened and closed, the more battery is used. This process occurs every time an app notifies you of new social activity.

The "chattiest" apps are Facebook Messenger, Yahoo Messenger, and Blackberry Messenger, as well as WhatsApp and Viber, according to the report commissioned by cellular network equipment maker Alcatel-Lucent. It evaluated the 40 most popular apps based on the live usage patterns of 15 million mobile phone users. Pinterest was also a big culprit.

Josee Loudiadis, Alcatel-Lucent director of network intelligence, said there was an art to balancing the demands of the app with the financial realities of delivering data across the network. While telcos and app developers largely ignore the problem today, she said increasing mobile network cost means that such complacency cannot continue.

"People will eventually say 'I'm not going to spend $200 on data'," Canada-based Loudiadis said in a phone interview.

She said email apps were among the most efficient ''signallers'' because they had to evolve in a time and place where mobile internet was very expensive.

"At some point, being able to make sure applications are well behaved, and not rampantly generating data'' was an area in which the telcos would ''want to collaborate with the app developers, to keep a check on costs."

In 2012, when Facebook integrated a range of new features into its Android app, Alcatel-Lucent reported that virtually overnight, signalling jumped by 10 per cent. With most of its billion users accessing the service through mobile devices, this seemingly smallchange had a huge impact on telcos. Facebook worked with Alcatel in the ensuing five months to develop a more efficient version of its app.

Facebook has taken steps to reduce the impact of signalling and published findings in a white paper released as part of the Internet.org campaign, a collective of companies and non-profit organisations working to make the internet more affordable.

One way it did this was by pre-fetching several images at a time rather than waking the radio separately for each image fetch.

"It is critical to wake the radio as seldom as possible and send as much network traffic each time as possible, while maintaining the feeling of freshness and recency in the UI," Facebook wrote.

In a 2012 study with the University of Michigan, American carrier AT&T found one app used 40 per cent of its power consumption to transmit .2 per cent of its data.

It said the single most important measure for app developers was to "transmit as much data as possible in a single burst and then end the connection.

"By specifically designing apps to minimise the time spent in full-power mode and thinking carefully about the trade-offs often required, not only do apps use less battery power, they respond faster to user input," the researchers wrote. "They become better-performing apps.

"This is good for users, who get a better experience and longer battery life. It’s good for network providers whose resources are utilised more efficiently. And it’s good for developers because their customers are happier."

Vodafone Australia spokesperson Elise Davidson said that because the telco holds spectrum across four bands, 2G, 3G, 3G+, and 4G, it doesn't have any network capacity issues.

"We're very comfortable with our network performance," Davidson said. "We have more than enough capacity."

Top five tips to reduce your iOS battery drain (overthought.org):

- Disable location and background app refresh for Facebook and apps you don't care about

- Don't quit your apps in multi-tasking

- Disable push email. Check your email manually.

- Disable push notifications for apps that annoy you.

- Enable airplane mode in areas of poor cellular service.

SMH.COM.AU

Picture: BLOOMBERG

Picture: BLOOMBERG

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