I have a Subaru that the battery goes dead when towing, so I just bought http://www.ebay.com/itm/301976566770?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT & have installed it on my car &...
I am not familiar with the battery maintainer you have, but I have towed my 2010 manual transmission Subaru as long as 2 days and have not had the battery go dead. Maybe you have some other problem.