Originally Posted By: Cutehumor
Originally Posted By: JHZR2
Does the phone accept charge another way? Might the computer and phone having been off have defeated some protective circuitry, allowing the battery to discharge below a threshold level? Battery management systems will not allow for a normal charge after an overdischarge due to safety issues.
If nothing charges it, I'd try warming the battery, but NEVER higher than 60c, to lower impedance and boost voltage a bit. This may allow the bms to allow the battery to accept a charge.
It charges through the same port with a USB cord or with an AC adapter. I don't have an AC adapter though. It was strange. the phone had maybe 2/3 battery when I was charging it. I left it charging through the USB on the laptop. My wife shut the laptop off while the phone was charging, the next morning the cell phone battery was dead. what should I try to use to warm the battery? There's a warning on the battery about not using fire or heating it. If it's not working, might as well see what happens, eh?
The electrolyte in a lithium-ion battery irreversibly degrades at temperatures over 65C. 60C is the hottest you want it to be.
That said, being 40C or so, just warmed up would help... you definitely do not want to overheat it - thermal runaway and fire can occur.
I'd just try to warm it up near an incandescent light bulb or similar low-level source of warmth.
The electrical safety devices will prevent a battery that is overdischarged from accepting a charge. I believe that there is no diode or discharge protection in the wire, and so current flowed from the battery back. I think that it allowed somehow an overdischarge, which can commonly happen, and now the safety devices will not allow a recharge. This is common, i.e. a "locked" battery.
If the phone is "locked", great. Perhaps the electrical safety devices are in the battery - and a dirty contact would prevent a proper voltage measurement, if that is how it is set up (I'm not completely sure how the safety devices are set up in a phone, to be honest, just larger stuff - but safeties DO exist in all Li batteries) Clean things up, Allow things to reset... But if you can put a multimeter on the contacts of the battery and get us a voltage, it would be real helpful to see where things are at...