Warning Console code page (437) differs from Windows code page (1252). 8-bit characters might not work correctly in PostgreSQL
When you use cmd.exe /c chcp 1252 in the batch file, you start a new command line, change the codepage for that and then that command line is immediately terminated, but the one that runs psql has not bee changed. 

Just put:

chcp 1252


(without calling cmd.exe) into the batch file.