I’m using a Fairphone 5 with e/OS 3.6 stable. Until now, whenever I didn’t need mobile data, for example, at home where Wi-Fi is active, I would turn off the “Mobile Data” feature.
Now, of course, I can have both mobile data and Wi-Fi enabled. Normally, Wi-Fi is prioritized. But how does this work technically? Is “mobile data” actually active, meaning does the device also communicate with the cellular network at certain intervals, or not?
It feels like the device uses more battery when both are enabled; am I mistaken?
I can give an example rather than explanation. I didn’t realise this part at the time but it seems my home router did not have a perfect connection to the exchange, but it managed OK. Two years later the router was replaced by an engineer as part of a job to fix poor landline function.
Meanwhile my first Android phone, /e/OS, was well connected to the router and using Wi-Fi but was switching to mobile data in a random way and generating Mobile data expenses. Seems mobile data was “filling in” but, inconsistently, Wi-Fi was not always playing the dominant part.
Developer options contains Mobile data always active. Once I switched this off my phone behaved well online. There was no issue that mobile data would not jump in appropriately when there was no Wi-Fi.
Once the router was replaced Mobile data always active was not used.
Apart from this example I believe from my experience Wi-Fi to be prioritised.
What I don’t know, in an environment with excellent mobile 5G would this be preferred over certain Wi-Fi? In an environment with imperfect mobile and / or Wi-Fi does the phone waste energy continually searching for best signal?
It depends on the stability of your wifi data connection. When you have an ordinary wifi environment (not the one from the neighbors in the 3rd floor …) the mobile data connection can consequently be switched off. This saves a lot of energy because keeping the mobile connection alive (over a distance of a km to the next antenna) costs much more energy than to the next wifi router.
