Cole Hersee makes a lot of products than might be helpful for RV owners. These include high amperage 12 VDC continuous duty solenoids, switches, monitoring devices and battery related products. Anyone seeking a boost solenoid can look at Cole-Hersee product #24213 for a replacement. Before making the replacement, make sure your boost solenoid is wired properly.

Commercial Vehicle Products
20 Old Colony Avenue
Boston, MA 02127-2467, USA

(617) 268 - 2100

They don't sell directly to the public but have a find distributor button on their web site.