# Connecting Positive power supply to power plane

I am making a four layer PCB. The top and bottom layers are signals and the internal layers are power and ground layers.

L1 --- Signal
L2 --- Power
L3 --- Ground
L4 --- Signal


I am using Li-ion battery and then using LDO to convert it to 3V. 3V is then powering the whole circuit. Should layer L2 should be connected to the 3V LDO output or Li-ion battery positive output? Both are a positive supply source, so I am unable to decide whether I should connect LDO 3V output or Li-ion output to the L2 power plane.