On Thursday, 31 December 2020 at 13:24:45 UTC, Paul wrote:
wrote:

Hi All,

Definitely a bit of an odd one this. The phone died last March (ish) with the symptom of not charging - left on for a few hours, no charging led and phone wouldn't turn on. Tried various chargers, leads, connecting it to a couple of PCs etc. nothing. Looking online there were a number of reset type fixes involving holding various button combinations, starting it with/ without battery etc. and no sign of life.

It was my wife's phone so she has been using an old iPhone 5 since which she hates. So... for Christmas I bought her a new Andorid phone. Yesterday I tried to get the photos off the old phone to put on the new one. No charging again so posted the above. After a couple of hours the charge in the phone went up very marginally but decided to leave it plugged in. All of a sudden, it seemed to suddenly charge (measured on MM to around 2v) and the led "I'm charging" lit up! Phone continued to charge as normal and now seems to work fine.

After all this there were only 2 (not interesting) photos which had not been copied to the server!.... I use an Android app which automatically copies all photos to my server via NFS for backup - it had been playing up resulting in you having to manually hit the upload button instead of doing it automatically. So given my wife rarely does it manually assumed there would be loads to do. Guess I should have tried to correlate the time stamps on the server with roughly when the phone died!

Anyway net result is she has a nice new phone and we have a spare if needed!

Anyone have any idea what suddenly spurred it into life? It was almost like it knew there was a new phone on the block Only thing I can thing of is that it has been in the cold utility room for the past few months - maybe this did something to the battery - like the "put it in the freezer" trick?

Thanks for all you help

Lee.
Lithium (all chemistries, like Cobalt or Iron Phosphate)
apparently do not have good charge acceptance at 0C or lower.

Not all charging chips are pro-active about this.
But this is some copied text from one chip that does care.

TEMP(Pin 1) :Temperature Sense Input Connecting TEMP pin to NTC thermistors output in
Lithium ion battery pack. If TEMP pins voltage is below 45% or above 80% of supply voltage VIN
for more than 0.15S, this means that batterys temperature is too high or too low, charging is
suspended. The temperature sense function can be disabled by grounding the TEMP pin.

Warming a Lithium pack up to room temperature before
charging, is a good practice for them.

Paul

Ah interesting... I wonder if when I was taking the voltage of the battery I inadvertently grounded the temp pin then. The battery pads are about the same width as my probes so very likely I inadvertently shorted some of the pads