While Android 5.0 Lollipop update was good news, it seems like many Galaxy S5 owners are facing issues related to WiFi connectivity. Many users reported that shortly after the update, their phones started to randomly disconnect from their WiFi networks and then reconnects after a few minutes.
The constant disconnecting and reconnecting will drain the battery quicker because it's not only the WiFi that's concerned here, also the mobile data.
When the phone disconnects from the WiFi network it's connected to, it will try to connect to mobile data so that users will have a "stable Internet connection." It sure will work with owners who have subscribed for mobile data, however, the phone will still drain the battery quicker.
To fix this problem, you may either turn off mobile data completely or prevent the phone from automatically switching between networks. Remember that once data is off, you won't be able to send / receive MMS or picture messages.
The second option is as effective as the first but you will still be able to send and receive MMS. Here's how you do it…
- From the Home screen, tap Apps icon.
- Tap Settings.
- Tap WiFi.
- Untick the checkbox next to Smart network switch.
I hope this helps. Let me know if you have questions.