As many have pointed out, I'm also experiencing sudden battery drains and shutdowns, specifically after the Lollipop update rolled out.
I have tried these steps in this order, same result no matter what I do...
Utilizing Stamina mode.
Wiping device clean and reinstalling software with Sony PCC.
Repairing software with Sony PCC.
Flashing a downgrade back to KitKat 4.4.4.
I thought the downgrade would work but apparently the damage done to the battery from the update is permanent.
Today, I ordered a new battery from China for $26.98 and I'm guessing it's probably some cheap knockoff that won't last very long if it works at all. But you know what? If it works at all it will be better than the current situation. I paid over $600 for a device that's ultimately rendered useless and more of a headache than an asset. What's worse, is no company will actually do the right thing and take responsibility to address the problem and make it right. Does anyone know of an actual phone manufacturer that manufacturers a phone that will actually work? It's insane that we as a people continue to give these corporations our money for products that work when we buy them, but within less than two years they are not worth the chewing gum stuck to the sole of our shoes.
I've had Samsung, it stopped working for no reason. Through research online, it's called Sudden Death Syndrome. What the blank is that?
Now here I am with Sony, battery is worthless. I keep it plugged in almost all the time now because if I try to do anything without it being plugged in it shuts down with no warning in the middle of tasks.
The only phone I've never had an issue with was the HTC Excalibur. I'm definitely going to go back to HTC after I squeeze a little more use from this Z1s so I don't feel like I got totally taken for a ride on this purchase.
If anyone has any suggestions that are actually beneficial instead of just tracking what apps use how much juice please respond. It's obvious this pandemic of battery damages are a direct result of the Lollipop update or a direct result of cheap manufacturing. Either way the least one of the corporations involved could offer is a new battery and a voucher to have it serviced somewhere locally.