Bad charger killed phone

[Griffin27WV]

I have a galaxy note 5 and for some reason thought that my 12v charger rigged up for my dash cam would be a good idea. Well my phone sure thought otherwise and boom instant paperweight. Phone has been unresponsive ever since. Any ideas to what I fried or is the whole motherboard toast? I would like to fix this myself but let my know If you have any ideas, Thanks!