LG Thrill 4G is actually the AT&T’s variant of the LG Optimus 3D. In terms of battery, the LG Thrill 4G uses same battery as LG Optimus 3D.

Type: Li-Ion
Voltage: 3.7V
Capacity: 1500mAh
Replace Code: FL-53HN
Compatible with LG Optimus 3D, Optimus 2X, Thrill 4G