Z5 marshmallow WIFI battery problem

[Drcspynz]

Since getting the marshmallow update my Z5 has shocking battery drain when on wifi. It's fine if switched to data. Have tried everything including factory reset.  Nothing shows in battery app usage as high drain.  

Have seen a very few others online with this issue but not many.  Any suggestions? 

[Drcspynz]

And I'm certain it's a software issue as it wantw the when it had lollipop.

[AliWonder]

 I have the same issue as everyone else here; the battery drains ridiculously quickly when everything is off & the screen is dark. How can apps be using up the battery when they're not even active?

I tried activating the 'Stamina' mode but it makes the screen go really dark so I can't read anything. Isn't there some way of having a stamina mode that doesn't affect the screen? I need it to be bright for my poor eyesight.

Does Sony plan to do anything to fix this issue?

[J-Mor]

Stamina mode is useless. I actually get better battery life with it off.

[Drcspynz]

Yeah that screen darkening on stamina is dumb and useless for many people me included. Grr.

[AliWonder]

Is there any way of going back to the previous version of Android? This is getting ridiculous. Today I hardly used the phone but I'm now having to charge it for the 3rd time in one day! It's simply not practical; I travel a lot and am frequently away from chargers for several days at a time; I cannot have a phone whose battery drains so stupidly quickly.

Hello - any Sony people out there? Is there going to be a fix for this?....

[Darbo25]

For now I'd just turn off your WiFi and stick to mobile data, that works for me, failing that you could turn your location off too as that worked for the other chap. Not ideal but better than constantly charging your phone.

[Drcspynz]

It is possible to go back to the previous version, (lollipop). 

You need xperifirm and flashtool and a bit of knowledge.

[AliWonder]

Thanks @Darbo25 - but I do have the WiFi - and the data switched off most of the time! I'm near a computer all day so I don't need it; I just use the internet briefly for a few minutes at a time throughout the day (either WiFi or network data). But the battery still drains horribly! It uses about 30% when I'm asleep - everything is switched off, the screen is dark - how can it possibly use that much when it's not doing anything?!

[Darbo25]

Leave the data on mate, it sounds silly but when I spent the day with both turned off my battery still drained, leave the data on for the day and see what happens

[AliWonder]

Thanks - but I don't understand how leaving the data on could possibly save battery use?..! Surely it will drain it even more? In any case I only have 3GB allowance for the month, so I prefer to just use it when I actually want to do something on the internet, rather than just leaving it connected all day; it will just use up my allowance for nothing!

I reapet my question: Hello - any Sony people out there? Is there going to be a fix for this?... We cannot surely be expected to just live with this awful situation? If so I will change to Samsung on my next upgrade, & say bye bye to Sony....