Xiaomi Mi5 - battery completely discharged

I have a Xiaomi Mi5 with Oreo. I took it out after not using it for a week or two and tried to power it up. The notification light flashed red and the battery icon appeared empty (no green) with 0%. It should have been fully charged as I always charge up this phone before powering it off.

This sort of thing has happened once or twice before and I have always attributed it to perhaps bumping the ON/OFF button accidentally and it then discharging while not in use. It is not my everyday phone so it lies idle (powered OFF) for several days at a time. But this time it lost all power except enough for the notification light and battery icon.

I would appreciate advice as to the possible cause and cure for this problem. I am going overseas and was thinking of taking this phone with me. The ON/OFF button is obviously too sensitive but the phone should not lose all power if just lying idle.

A brief bump of the Power button shouldn't start the power up process -- it's typically a longer press of it. Did the phone charge up normally after you found it like this? Was the phone stored in a very cold or warm environment? Either of those could potentially lead to battery drain, even while off.

I can offer no answer, but have experienced similar: a Lumia 550 that would partially drain when powered off; and my laptop, which fully drains, given enough time. The Lumia corrected itself for no reason I could identify and now retains its charge. The laptop still does it, and I tired of trying to diagnose and fix it long ago.

I guess that a short circuit could be responsible, but it would take repairer diagnosis to discover it.

Thanks for your replies.

No - the device was not stored at extreme temperatures. Yes - it did charge up normally 0% to 100% without trouble. As for short circuits, I would not have a clue. Any hardware approach to solving this problem is impractical as the warranty is long expired. The ON/OFF button is VERY delicate and I have powered it up before accidentally usually noticing it before it loses too much power.

I will reset and restore the device and hope for the best.

It's worth pointing out that when typing this reply if I rotated the screen or placed the device down on a firm surface the draft reply would disappear and I would have to start over again. I finished the reply on my laptop.

Thanks

If you don't already have a case, I'd consider finding one that has its own button that overlays the phone's button. This often makes the button a little stiffer, thus making it harder to press accidentally.