Standby power consumption is one of the few battery life parameters provided by practically all smartphone manufacturers.
Typically the claim is something like "up to 14 days", but how that kind of battery life can be reached ? We tried to find out with Huawei Honor 7.
Who just keeps the smartphone on standby, day in day out ?
Probably no one.
Instead, the active hours are only increasing and you have to charge the device every day. So, you could argue that standby power consumption does not matter at all. However, in real life, you can easily lose 10-15% of battery capacity per day by just being in standby mode. In addition, a good standby performance typically indicates good quality and maturity in the device software.
In our measurements, Huawei Honor 7 active standby consumption was 86mW. Huawei's claim is 350h of standby time, which equals about 30-35mW consumption.
This huge difference is explained by the differences in the definition of standby. Our active standby is based on real life use. The device is in cellular standby, WiFi & Bluetooth are turned on and there are several accounts active (Facebook, Messenger, Twitter, Play).
In measuring standby, the device manufacturers typically take the 'smart' out of 'smartphone' by turning everything off, except the cellular standby. Basically they are telling an "alternative fact" about standby battery life.
We selected Honor 7 for our study, because it had the biggest difference in our measurement vs. the manufacturer claim. One by one, we started to disable features in order to reach the claimed standby level. The results are in the table below.
|Facebook off||66,5||Singled out as the account having biggest effect on standby|
|Other accounts off||40,5|
|WLAN off||34,5||Manufacturer claim reached|
As you can see, the accounts have the biggest impact on standby. If you feel like losing a lot of battery capacity in standby, it is a good idea to check your accounts and disable the ones you don't need. Android does have a Doze Mode , which should automatically disable accounts of less importance during inactivity. However, we have noticed that the phones are quite picky in entering and staying in the doze mode, making it a bit unreliable in real life usage.
Unfortunately, uninstalling apps with connected accounts sometimes caused serious standby issues. It seemed that getting into sleep mode (=the lowest power consumption state) gets randomly blocked for several minutes, which increases the standby consumption over 500%. Disabling mobile data fixes the problem, but is obviously not a proper solution.
We also detected periodical but irregular extra activity, which added 25% to the cellular standby consumption. Sometimes it was there, sometimes not.
It is quite common to find these kind of issues in standby, not just in Honor 7 or Android OS but in all products and platforms. The issues are not easily detectable by the end-users, so fixing them is typically not a priority. However, issues in standby may lead to serious battery life problems for some users and they can be very frustrating. As mentioned, standby performance is a good indicator of software maturity and quality...
We will continue looking into standby power consumption issues, as well as deep diving into Doze Mode. Stay tuned!