I let my phone go completely flat the other day. I'd gone away for a week and had forgotten to take my XL with me, came back, plugged it into the charger for an hour, and nothing.
I do notice that after removing the battery, putting it back together, and plugging it into the charger, the LED flashes red 9 times (exactly 9, each time i do this). I cannot find anything that mentions 9 red led flashes in forums, docs or google.
I'll leave it to charge overnight, see if that makes a difference, but am a bit worried about it all (bought the XL in Singapore, and I'm in Oz, and only have Singapore warranty).
On side note, phone is rooted, the chinese recovery flashed (anzhi?) with bindroid rom flashed.
I'll see how I am after 12+ hours charging, but any suggestions/advice would be most welcome.