Bang Bang
Age is a state of mind.
I understand the logic but even after making that long pull when Lance was dead in the water at GSMTR and I had to pull him up that hill I didn't have any trouble. We did stop every few minutes to give the winch a rest as it was getting hot. That was probably pulling for a good 45 minutes or so.....pull for 5, stop for 5 - 10 minutes. Just seems to me that as long as you don't kill the engine after winching for long pulls you will be fine. Oh, and I usually carry a set of jumper cables with me....... 
I would think that you would experience what Larry has seen, popped solenoids or even an over heated winch motor, before you would have battery issues as long as the engine continues to run. I do agree that a dual battery set-up would be CYA but I haven't found the NEED for it yet.
I would think that you would experience what Larry has seen, popped solenoids or even an over heated winch motor, before you would have battery issues as long as the engine continues to run. I do agree that a dual battery set-up would be CYA but I haven't found the NEED for it yet.