I been using a connection from the MH #4 pin directly to the car battery.Using # 12 wire with a 20 Amp beaker on each end.Because of the
wire lenght and the drain in the car and the load of the Brake-Buddy,you will not have any over-charging problems.
Been using this setup for about 8 years with no problems.
Siggy
Happy Trails
Siggy & Ursula
2011 Dutch Star 4020,ISL 400,Compr.brake,FTL XCR,IFS
Allison MH3000
2015 Jeep Cherokee,4x4 Active Drive II,V6 , Brake Buddy,Roadmaster Sterling,
Camping since 1975 Pop-Up,1986 22Ft.TT,1999 Gas MH,2005 KSDP,
2011 DSDP,FMCA 368283