dwh
Tail-End Charlie
Well, the first thing that strikes me is that it's a winch in a cradle. That means hitch receiver. That means, when the winch is in use in the rear, the trailer won't be hooked up, which means running the winch off the trailer batteries is probably a nogo.
Unless the winch is being used in a hitch receiver in the back of the trailer.
So I would probably...
Leave the factory alternator wiring alone, it's adequate for whatever the alternator can be expected to produce.
Run big wire from engine battery through 500a rated ACR, then Y to front/rear of truck Anderson connectors.
When engine is off, front/rear Andersons are dead unless the ACR is forced on. When engine is running, front/rear Andersons are hot unless the ACR is forced off.
Front can be used to power winch. Rear can be used to power winch or charge trailer batteries.
If winch is used in front and the trailer is connected - AND - the ACR is forced on, the power will flow from engine battery (cranking batteries are better for short duration high amp winch pulls), supplemented by whatever the alternator can produce, further supplemented by the trailer batteries.
Which shouldn't be necessary unless doing all day winching. But even then, electric winches have duty cycle ratings and mandatory cool down periods...the trailer batteries probably won't actually be needed.
Unless the engine is stalled. In that case, the trailer batteries might save the day. Maybe. Depends on how much winching is needed to save the day.
The trailer could also be wired with Y cable and front/rear Andersons. Probably easier to use a marine battery switch as a disconnect instead of bothering with an ACR.
And the trailer will need a front Anderson anyway to charge the trailer batteries off the truck.
If there is a hitch receiver on the rear of the trailer, then the winch could be powered by trailer batteries, engine battery and alternator, or if unhooked from the ruck, trailer batteries alone (for a while anyway).
Unless the winch is being used in a hitch receiver in the back of the trailer.
So I would probably...
Leave the factory alternator wiring alone, it's adequate for whatever the alternator can be expected to produce.
Run big wire from engine battery through 500a rated ACR, then Y to front/rear of truck Anderson connectors.
When engine is off, front/rear Andersons are dead unless the ACR is forced on. When engine is running, front/rear Andersons are hot unless the ACR is forced off.
Front can be used to power winch. Rear can be used to power winch or charge trailer batteries.
If winch is used in front and the trailer is connected - AND - the ACR is forced on, the power will flow from engine battery (cranking batteries are better for short duration high amp winch pulls), supplemented by whatever the alternator can produce, further supplemented by the trailer batteries.
Which shouldn't be necessary unless doing all day winching. But even then, electric winches have duty cycle ratings and mandatory cool down periods...the trailer batteries probably won't actually be needed.
Unless the engine is stalled. In that case, the trailer batteries might save the day. Maybe. Depends on how much winching is needed to save the day.
The trailer could also be wired with Y cable and front/rear Andersons. Probably easier to use a marine battery switch as a disconnect instead of bothering with an ACR.
And the trailer will need a front Anderson anyway to charge the trailer batteries off the truck.
If there is a hitch receiver on the rear of the trailer, then the winch could be powered by trailer batteries, engine battery and alternator, or if unhooked from the ruck, trailer batteries alone (for a while anyway).