Wow...fast response. I hope I answered your questions. I love mine. I used to see my main battery get VERY weak if I used the plow and lights a lot. Alternator had trouble keeping up when the engine was "stop and go" during plowing.

Yes....wire everything that is not essential when you are doing normal driving off of the aux battery. That will keep the main battery load to a minimum and increase the odds of getting a good strong start every time. If you do get a dead main battery, chances are the aux will be good enough to give yourself a jump. Mine has saved me a few times when I left the headlights on. You could still wire in a solenoid to give yourself the jump, but for as often as it happens it would probably be wasted effort, and if you forgot to turn it off, you'd be right back where you started.