Forum Discussion

Rikilee's avatar
Rikilee
Explorer
Oct 23, 2019

Switching from AC to Coach batteries

When I unplug my motorhome from ac power or when there's a power outage, I have to manually switch to Coach batteries.

I thought the Coach should switch automatically. Is this normal or do I have an issue?

7 Replies

  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Rikilee wrote:
    When I'm plugged in to power the battery disconnect switch is on. it has a green light. We had a storm which caused a power outage and I had to physically push the Coach battery switch on. The second time was when I unplugged from campground to travel, again noticed I had to push switch on to battery power.

    Thank you for the replies. Really appreciate the assistance


    One thing you need to know. On my system the light is red but it does not indicate the state of the disconnect switch (unless I'm unpluged) it indicates only that the house has power (12 volt side of house) not the source.

    Now; your house has 3 or 4 power systems
    1: 120 volt shore power (or generator power)
    This runs Air Conditioners. water heater. Fridge and entainerment. and outlets.
    2: 12 volt "house power" Lights, Fans, Furnace, CONTROL power for Water heater, AC and fridge. In some cases may also run fridge but I do not recommend that. .
    3: Vehicle Chassis 12 volt system.. on a Trailer that's the stop/tail/turn and marker lights. on a motor home add motor and headlights, Defrostor Dash HEVAC and so on.. All the "Truck stuff"

    And optionally a 2nd 120 volt "inverter" circuit. Now this often runs the TV's. and in my case the microwave and GFCI outlet and protected outlets.

    IS this the one you need to turn on?

    My inverters have a UPS feature. they pass shore power (At the moment) and if some 10 T type (that's 1 D 10 T) slams into the turn at 90mph in the 55, wipes out and slams into the pole... The inverter takes over so fast the TV does not even blink. PROVIDED I HAVE IT IN UPS MODE (Standby) If I disable the inverter. All goes black.
  • leave the battery disconnect on at all times unless in storage.
  • Rikilee wrote:
    When I'm plugged in to power the battery disconnect switch is on. it has a green light. We had a storm which caused a power outage and I had to physically push the Coach battery switch on. The second time was when I unplugged from campground to travel, again noticed I had to push switch on to battery power.

    Thank you for the replies. Really appreciate the assistance


    On most motorhomes, when the battery disconnect is OFF(light off) and you plug into 120 shore power, the charger system comes online and that disconnect light will be ON, but the batteries are not connected. Now, to confuse you more. lets say you do have the battery disconnect ON(indicator light is on), you plug into 120 shore power. IF you turn that battery disconnect to the off indent, it will indeed disconnect the coach batteries BUT THE INDICATOR LIGHT WILL STAY ON, due to the Converter/Inverter-Charger still supplying power. Not all motorhomes react this way but a lot do. You need to state Year/ Brand/Model of RV. Doug

    If your RV is the 1990 model listed in your profile, then the odds are it is what I am stating to you.
  • When I'm plugged in to power the battery disconnect switch is on. it has a green light. We had a storm which caused a power outage and I had to physically push the Coach battery switch on. The second time was when I unplugged from campground to travel, again noticed I had to push switch on to battery power.

    Thank you for the replies. Really appreciate the assistance
  • You probably have the Coach Battery disconnect OFF. When plugged into 120 AC power, with the disconnect OFF, the Converter or Inverter/charger will supply 12 volt power. ALWAYS leave the battery disconnect ON when using the RV. Now, if you are not talking about having to turn the battery disconnect ON, Then you do have a problem. Doug

    PS, there is no switching needed when you unplug AC power---2 different systems.