I installed this product, does not work, by that it only keeps 2nd battery charged. You cannot crank off 2nd battery if your main battery is dead. Painless mgmt factory recommends you do not hookup any electrical items to 2nd battery but only to main battery? SO why do you need 2nd battery? My 2011 GMC Sierra has had both batteries dead and I was stuck. Pain Less mgmt system shorts out and drains both batteries. Go with an isolater (DB Electrical) has them easy install and you can have 2nd battery to use for all electronic gadgets.
