I have a big rig also with slow landing gear. Was told this was normal for the size. Was also told I could add a second motor to assist. Decided to stay with the normal slowness and not add another motor witch could become another problem. I do, however, connect the power to my TV before I go up or down with the rig. The motor will drain your batteries. I also have a generator with I might fire up and use instead of hooking up to the TV. Happy Pulling.
