I have an Auxiliary battery installed in my truck. I havea 2009 Chevy Silverado 1500. I'm running dual optima yellow top's. Out where Ilive we have hot freaking summers 105+ and 10 degrees or less is easily scenein the winter dead batteries are common. Batteries don’t last that long. I havea battery solenoid type battery isolator that is activated by a switch wired tomy dash. I have been looking into an on board charger. I have checked out acouple different 12v to 12v on board 3 stage charging systems. Has anybody hadany experience with these types of systems? Does anybody have any recommendations?