Water damaged PS4 controller

My controller ended up in the water for about 5 second, I took it out, dismantled straight away and dried, cleaned with isopropyl, put everything together and it works perfectly fine but ONLY when on charge, when i disconnect from charging the light goes off straight away. I have another controller that I took apart and swap the battery and back panel and still the same issue, when I put battery and back panel from flooded controller to the working one everything works, no issues. Tried resting controller with pressing the reset button for 10 second but nothing changed, is it beyond repair? what should I do next?