Forum Discussion

maxheller's avatar
maxheller
Explorer
Oct 03, 2023

Disable alternator charging of house battery

Hi everyone,

Does any of you have any experience in how to install and wire a manual switch to disable alternator charging of the house battery via a latching relay? I have a Trombetta Latching Relay (684-1261-212) installed in my 2023 Thor Chateau 22E, which is controlled by Intellitec Delay Relay (00-00629-120). If believe this is a common setup.

I would like to be able to disable / enable the alternator charging (and emergency start in the other direction) via a second switch. Reason for this is that I am planning to install LiFePO4 batteries and a DC-DC charger, but would not like to lose the emergency start feature.

Has any of you done this or has a good understanding on which wires need to go where into a manual switch?

The Intellitec Delay Relay (00-00629-120) has a wire that is tied to the iginition, so I was thinking about using this wire to go into a switch. Any thoughts?

Thanks.

Max
Class C
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Oct 03, 2023
    That is not a latching relay which is a different design. Install a cab switch to supply 12V to activate as needed and eliminate the delay relay, You can reuse the ignition wire but connect the switch to the house battery because the chassis battery may not be able to engage the 684 relay when it's discharged, hence no emergency start. Of course you have to remember to turn off the new switch except for emergency start.
  • Grit_dog's avatar
    Grit_dog
    Navigator
    Oct 03, 2023
    I’d suggest that if you have to ask, then don’t touch it.
    Besides, you’re trying to create a solution for a problem that you dont have.
  • CA_Traveler's avatar
    CA_Traveler
    Explorer III
    Oct 03, 2023
    Or unless you discharge the chassis battery often disable the two relays and jump start the two battery banks if required.
  • VA-Apraisr's avatar
    VA-Apraisr
    Explorer II
    Oct 03, 2023
    I'd carry a jump box rechargeable battery for an emergency.....I have lithium batteries with DC-DC charging setup and ideal to arrive wherever with a fully-charged house battery setup. You may forget to put switch in charging position and lose all that charging while driving.
  • JaxDad's avatar
    JaxDad
    Explorer III
    Oct 04, 2023
    This would be a *very* simple change if you only want it to be manual. Simply put an old school ‘constant duty’ relay, common & cheap as dirt, inline between alternator and house batteries. On older C’s it was mounted on the drivers side inner fender.

    These were commonly called a ‘Ford starter relay.

    In your case the trigger circuit would not be connected to an ignition switched hot wire, it would be connected to a mechanical switch on the dashboard instead.
  • Grit_dog's avatar
    Grit_dog
    Navigator
    Oct 04, 2023
    Ha, they’re still Ford starter relays to me.
    Still not understanding the need to add, basically a disconnect, or 2 disconnects. One on the charge line and one on the emergency start line. And isn’t the emergency start already disconnected unless it’s activated?
    Or are you saying you will have a “dumb” DCDC charger and you’re worried about overcharging the house batteries? In that case, a simple Ford starter relay seems appropriate and easy

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