Help: what's draining my battery?

[mothershipload]

Last night was the first time it happened, plugged in to a normal charger (not the fast charger that came with the phone, I leave that fast charger downstairs in my kitchen for quick charging as needed). Woke up this morning, saw only 57%. Got to work, 47%, plugged into my PC usb port, now about 3 hours later it's down to 38%!. Obviously, something is wrong. I have been receiving and sending several text messages at work, nothing outrageous, total of about 14 messages. Any advice is appreciated!!!

 

[Ranny99]

Try running it naked for a day or so (some cases are causing problems with constant waking) and delete facebook/messenger. See if it improves at all.

I went from losing 70% overnight, totally running out and missing my alarm to a 3-4% overnight loss.

 

[Rukbat]

Since the only thing you changed was the charger, I'm guessing that the charger you used can't supply enough current to charge th phone as fast as the stock charger can. The less current available, the longer the charge takes. (And if the phone is turned on while being charged, and uses more current than the charger can supply, the battery won't charge, it'll just discharge slower with that charger plugged in.)

You have to read the output current on the labels of both chargers to know what's happening.

As far as the battery itself, first DON'T let it fall below 40%. (It doesn't matter what you need the battery needs to not drop below 40% or you'll shorten its life.) So if you regularly drain the battery way down, even a battery that's a few months old may not be holding a full charge any more.

Second, you started with less than half a charge (dropping from 57% to 47% means that it was at 57% with the charger plugged in, but it was probably at about 48% actual charge), so it's going to get down to 38% a lot faster. (That would be like 75%-80% from a full charge after 4 hours.)

(The "State of Charge" that the phone shows is actually the battery's under load terminal voltage, compared to 3.60 Volts [some manufacturers overcharge the battery so it seems to last longer - it may, but that shortens the life]. If the charger is plugged in, the voltage will be higher, so the SoC indicated will be higher than it actually is. Since there's no way to electronically measure the SoC, that's the best we can do, and let human intelligence fill in for the inaccuracy.)

@Ranny:
If the only thing that was changed was the charger (and the amount of charge to start the day with), neither wakes nor "running naked" would be the cause, since nothing changed but the charger and amount of initial charge.

 

[mothershipload]

You might have hit on something there! I do notice that the phone feels warmer than before. I'm gonna remove the case for now. Will report back.
Thanks,

 

[mothershipload]

Rukbat,
Thanks for the explanation.
However, I've been night charging the phone for 2 months with a normal charger (from my Note 2). THe phone has always gotten to 100% by the time I wake up, I usually go to bed around 11 PM, up at 6 AM. The fast charger I only use occasionally during the day, to "top off".