• Research Questions

For this project, I am going to visualize my iPhone battery usage in the last 10 days. I just upgraded my phone to iPhone XS about a year ago. While this product is said to last for up to 12 hours of internet use – according to Apple’s advertised claims – I notice that I charge my iPhone more frequently than every 12 hours. This made me wonder, why is my phone’s battery draining so fast? Which apps contributed to my battery usage? What is the proportion of battery used for screen on activities and screen off activities, respectively? At what time of the day does my phone battery usage soar?

• Audience

I am the primary audience and beneficiary of this research. Despite that mobile phone constitutes an indispensable part of my life, I have never thought about how I use it every day and its impact on me. For example, a glimpse of my phone battery usage reveals that my screen was on for 6 hours yesterday, and I spent 10 hours in total on Candy Crush Saga in the past 10 days! Thus, understanding my phone battery data may serve as a reminder and help me spend my time wisely in the future.

Moreover, visualizing how long each app was in use on-screen or in the background allows me to make informed decisions to help prolong my phone battery life. For example, if an app is using a lot more battery power than others, I may remove or replace it. Or, if I know I need to save battery on my phone in certain periods of time, I can simply close out some apps or disable background operations within an app’s settings. In a word, this research will help me monitor and improve my life in the future.

• Data and Visualization

The data is gathered from my iPhone. iPhone collects battery usage data from both the last 24 hours and the last 10 days. Specifically, it includes the last charge level (0% – 100%), how long each app was in use (minutes) and its proportion of battery usage (%), battery usage during different time periods (e.g. 12am, 3pm, etc.), and the amount of time when the screen was on or the app was operating in the background (minutes).

I will visualize four things: 1) daily battery usage over the last 10 days; 2) the proportion of battery usage for the major apps over the last 10 days; 3) screen on activities and screen off activities over the last 10 days; 4) battery usage during different time periods in the last 24 hours (morning, afternoon, evening).

Figure 1 Daily Phone Activity in Minutes

Figure 1 shows the daily phone activities from Oct. 12^th to 21^st. According to the line chart, my phone has less activity on Oct. 19^th and 20^th, which are the weekends. On the contrary, the peak of my phone activities falls on the 15^th, which is a Tuesday. The fact that I rely more on my phone on weekdays may due to the fact that I was busying writing up my assignments and thus used Safari a lot (to search for references). I choose to use the line chart because I want to see the trend of my phone activities over the last 10 days.

Figure 2 Proportion of Battery Usage for the Major Apps from Oct.12^th to 21^st

Figure 2 talks about the proportion of battery usage for the major apps over the last 10 days. For example, I used Safari for 992 minutes during the last 10 days, which accounts for 35% of the total battery usage. Interestingly, the second most frequent app that I use is Candy Crush Saga, which accounts for 24% of the total battery usage – I really spent a lot of time on Candy Crush over last 10 days! Here I choose to use the pie chart, since it helps to visualize the proportion of each app’s battery usage.

Figure 3 Screen On Activities from Oct.12^th to 21^st

Figure 4 Screen Off Activities from Oct.12^th to 21^st

As I want to see which app uses a lot more battery power than others, I make two pie charts to compare the screen on activities and screen off activities. The sum of the screen on activities is 3,093 minutes, and the sum of the screen off activities is 742 minutes. Compare with Figure 2, the screen off time is not causing much battery usage. For example, Eudic (an English dictionary) uses 364 minutes of screen off time but just accounts for 1 percent of the total battery usage. However, even though I haven’t opened QQ Mails, it still causes 1 percent of battery usage. Therefore, a wiser way is to turn off all the apps while not using it.

Figure 5 Phone Activity during Different Time Periods in the Last 24 Hours

In Figure 5, I visualize the phone activity during different time periods in the last 24 hours. I choose line chart again, because it can visualize the trend in data over intervals of time. As we can see, I use my phone a lot in the morning and at night. Except for nighttime while I am sleeping, I use my phone almost all the time. It should be noted that, however, the data includes the off screen activities as well, therefore, it might not be accurate enough.

• Next step

The data only includes 10 days of the phone activities; any data longer than 10 days will be erased. Future study should collect data over a longer period of time, for example, a month, or a year, to make the conclusion more convincing. In addition, I would like to calculate each app’s battery usage per minute to further investigate which app is more energy efficient.