Drained battery is permanently dead?

Unfortunately not, and even if you could, according to Batteryuniversity.com, you should avoid using it, as the internal safety circuitry has most likely been damaged.

"Some lithium-ion batteries fail due to excessive low discharge. If discharged below 2.5 volts per cell, the internal safety circuit opens and the battery appears dead. A charge with the original charger is no longer possible."

Yup, the recommendations I've seen is to shut it off at 10%, never let it get below that. That's where something like Battery Booster comes in extremely handy. You can set it to turn off bluetooth and/or wifi at a certain battery level, and to notify you when it gets to a certain level as well.

If you're using it to connect to your computer, I'd also recommend Remote Notifier and its companion Desktop Notifier, which do growl/popup notifications on your computer screen so you won't miss them.

BTW, internal safety circuits are what keep them from overcharging, and the lack thereof is why the generic Chinese batteries off Ebay are not a great idea and have resulted in blown up computers and cell phones because there's no shut off valve, so to speak.

http://batteryuniversity.com/learn/article/safety_circuits_for_modern_batteries

  Hey everyone this is a quick fix for your problem.  The battery is a battery and if you know about electrionics they hold a better charge when cold.  Put it in the freezer for a couple of minutes then take out and directly put it on the charger.  Trust me it happens to me all the time and it works.  That will give your batter enough jucy to activate the port so it will charge.  Only if its a good working batter.  Also use the wall plug.  Usb's don't put out the electricity you need to get it charged quick enough before it would go out.  Trust me i did this with my evo

Ok, let me start off by saying I am new to this board, but I feel that this needs to be said.


TarrantCounty,

YOU ARE A GOD!!!!!!

I bought my EVO4G on friday, I have had it for 2 days.  I have only charged it once and I am one of those people who believe to kill the battery before charging.  Soooooo, I was messing with my phone, trying to learn how to utilize all the features, so I figured, hey if I am going to charge it, I might as well hook it up to my computer and charge it while I transfer some music files.  Yeah, in the middle of that, the phone completely died and wouldnt take a charge at all.
Needless to say, I went into a panic.  Big Panic.  I googled problems with this phone, came across this site, read what TarrantCounty had suggested and BAM!!!  Now the phone is taking a charge!!!!!

THANK YOU VERY VERY MUCH!!!!!!

Magpul

  Thanks all I think this save my data...will update...

If your battery is dead and the freezer method doesn't work, then you've likely irreversibly triggered the safety shut off and the battery will need to be replaced.

I deal with this issue by using cheap Chinese batteries and the Sprint Protection Plan...