I have the 2150MaH

[CuhRazy]

I have the 2150MaH extended battery and charged it all night, its already down to 90% and its only been off the charger for 10 minutes. Whats the problem?

[jpd]

It is annoying but normal. There is a good explanation of what is going on here.

Your battery gauge is lying to you (and it's not such a bad thing) - xda-developers

Basically smart phone developers have 3 choices when it comes to charging lithium ion batteries. What it appears they do is allow the phone to reach a complete charge then the phone shuts off the charging. It then loses a bit of the charge over the next hour or so until it hits 90-94% when the charger kicks in again and recharges to capacity. The reason it does this is if it charged the phone to capacity and did not stop charging it would decrease the life of the battery. Kind of like if you overstuff a box over and over, eventually the box will split and fall apart.

The developers now have the choice of either having the phone read 90-94% and have people thinking their chargers are defective and wonder what is wrong with their phone, or read 100% and quickly lose 6-10% of the power over a couple of minutes and wonder what is wrong with their phone. It seems most developers go with the latter option.