My batery is not charging when my computer is turned on just when off

i have a mack book pro and since a few days is not charging my batery when my computer is working just when is turned off; sometimes keeps working normally and after some moments happens the same issue, the battery have 500 cycles and i tried changing the battery for another goo and it´s the same, then i try another charger and same, i did the steps to clear or fis the smc and vram but nothing changed, now i will try to change the mag safe dc if maybe would be that but i don´t know what is really happening! please help me to fix this issue!