Even though filled with copper or anything the connection area to inner layer is still limited by the hole diameter and copper thickness.
Example: hole diameter 2mm, copper thickness 35um
pi * 2mm * 0.035mm = 0.2mm2
I wouldn't use 0.2mm2 wire for 300 amps.
Another thing are those thermal reliefs with 10 mils tracks (estimated from the picture peranders posted). Those are not 300A stuff either.
Example: hole diameter 2mm, copper thickness 35um
pi * 2mm * 0.035mm = 0.2mm2
I wouldn't use 0.2mm2 wire for 300 amps.
Another thing are those thermal reliefs with 10 mils tracks (estimated from the picture peranders posted). Those are not 300A stuff either.