I am a engineering tech electronics - This is just general info- I would take a amp meter(most DVM's have the ability to read 10amps dc)
leave the key off ! / don't try and start with the dvm hooked up you will exceed the 10 amp in a heart beat even turning on the lights will exceed the 10 amp fuse in the DVM.
But anyway remove the pos(+) cable & hookup the amp meter between the cable & battery- there is going to be some current draw IE- clock/radio memory but it should be low level. you should be able to see the current draw just by opening the door and see what the interior lights pull just as a test. If it seems excessive with all lights off/key off( i am just guessing .3amps or 300millieamps or higher 1amp=1000millieamps) start pulling fuses tell it goes away and see what that fuse controls.
front end damage may have pinched a wire somewhere ? not sure if this will help or not / but you need to see @ the very least how much power is being pulled with the key off. Hell you may just have damaged the battery and its not holding a charge anymore
Good luck het