Ckt to switch 12VDC Supply from RV Batteries to Tow Vehicle supply

Discussion in 'The Projects Forum' started by Mustang1965, Feb 20, 2013.

  1. Mustang1965

    Thread Starter New Member

    Feb 20, 2013
    6
    0
    Hi,
    I am trying to design a circuit that will automatically SWITCH the RV's 1500 watt Inverter 12VDC supply source from the RV Batteries to the Tow Vehicle's (Truck) 12VDC supply, when the truck is connected to the RV. Currently the 12VDC from the truck is connected directly to the RV batteries. The truck only puts out 12.5VDC (30Amps) while the inverter provides its 120VAC output tied to the RV's Battery controller which produces 13.2 VDC (Smart system). We like to leave the RV's Refrigerator running on Electric while traveling and not on GAS. I currently leave home with the batteries fully charged at 13.2VDC and when I arrive at the campsite they are at 12.5VDC. Not good when I want to dry-camp for a few days. By tieing the Inverter to the Truck and not to the batteries while traveling, the inverter supplies the RV with 120VAC and also keeps the RV's battery controller charging the batteries at 13.2VDC.
    I was thinking of a high amperage diode between the truck and RV, and switching the circuit on the RV side of the diode. I could then connect the coil side of a NO/NC relay to the truck side of the diode which would switch the connection from going to the battery (NC) to connecting to the Inverter. I have 2 Beuler 12V 40/60Amp relays (BU-5084M-000) that I will be using. Just need to know about the DIODE part to use?
    Sorry about how long this is.
    Don
     
  2. Mustang1965

    Thread Starter New Member

    Feb 20, 2013
    6
    0
    STOP, I located a part that will work perfectly. It is a 30 Amp BLOCKING DIODE used in DIY wind generators. Problem relsoved.
     
  3. DickCappels

    Moderator

    Aug 21, 2008
    2,647
    631
    Although you no longer need further input, I will still volunteer that you will loose a lot of power (tens of watts) in the diodes. If this turns out to be an issue, then a really good high current relay would be a good solution.
     
Loading...