Will my deep cycle battery protect itself from full depletion?
Yes deep-discharge batteries can handle many more cycles than 50 for flooded cell lead-acid batteries ( some barely survive a few )
But they still oxidize the plates with a thin coating from the calcium-lead plates over time from under-voltage.
This can be reversed with very fast rise-time pulse charging, but otherwise, they will become high ESR and unable to prove the amps you need.