I use a wench to drag logs onto an 18 ft trailer to cut up for firewood.
I used light welding lead from the truck battery to the rear where I plug the wench lead into a 50amp stove outlet.
Keep the truck idling and you battery doesn"t die. I don"t use the wench enough to justify a battery that will probably be dead the next time I need it and the welding lead, outlet and connectors cost considerably less than a heavy battery does.
TyWrap the welding leads to the frame and use red electricians tape to identify the hot leg.
The local electrical supply house had welding lead for a good bit less than the welding supply, too.