According to Bennett Price :
As others have pointed out, the CCA rating doesn't help. I suggest you
buy a cheap ammeter at the auto parts store and measure the current draw
of your new winch, (including when it is locked - trying to pull
something that simply won't move.) Then you can consider whether to buy
a battery charger, extra battery, or AC-DC converter.

Trying to stall a winch can be rather hazardous.

Finding the amp rating of a comparable winch should serve for
a good ballpark number.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.