Is 12v constant from hitch actually necessary?

smkettner wrote:
If you start fully charged and always arrive at the destination with power to plug in then no go ahead and pull the fuse.

If and ONLY if you know that your battery (ies) will not discharge below voltage needed to apply brakes to your rig if it should become detached. How is one to know if the batteries are being discharged below the safe level while driving without charging thus shortening their life?

My trailer has a gas/elect fridge, as most of us have, that needs 12v to operate the gas burner when in gas mode. There's also smoke detectors and other such things that use 12v that will drain the battery if the TV didn't keep it charged.

If you start fully charged and always arrive at the destination with power to plug in then no go ahead and pull the fuse.

I don't unhitch or unplug when stopping for one night if I can possibly avoid it. If we're stopped for two nights or more we're going to need the truck so everything gets disconnected anyway.

I doubt it would be possible to pull all three batteries (two in the fiver and one in the truck) down to any significant degree in one night, and it certainly isn't going to happen with our usage habits.

The battery charge wire is there to ensure that the trailer battery is sufficiently charged to operate the trailer breakaway brake system should the trailer become unhitched from the truck. My truck keeps pin #4 hot continuously as well, and I would never even think of disconnecting it.

Rusty

So you use no lights, no music, no water pump, no furnace, no roof vent and don't recharge a cell phone or laptop?

If you use so little power, why worry about it drawing down the TV battery?

Bill

Yes, it charges the battery while on the road.
You should add a relay to isolate the trailer charge wire from the Chevy.