question

The ignition switch should have an 'AUX' connection that provides 12v when the switch is in 1st & 2nd positions, but not during 'start' (3rd). This wire normally provides power to the radio, and other circuits like the interior lights. I would use this to power a small 12v relay( dpdt), and connect the relay contacts to the Orions, rather than connecting directly.

The cable you run to the Orion to switch beeds a small! fuse, so don’t connect it to the cigarett lighter, which is a huge energy consumer. Find the ignition wire as previously stated. If you do short cuts your van will soon be up in flames and also no-one will find his way around when installing or repairing/ lioking for faults in tge future.

When using two Orions in parallel you will most likely fry your alternator, especially when your engine is idling it wont have enough cooling. I have a 90A alternator in wont connect more then one 35A Orion on it. So first check how big your alternator is before adding loads to it

My understanding is that the H&L control inputs need to be jumpered together to keep the Orion-Tr Smart units OFF. And that when the H&L inputs are not connected to each other, the Smart Orion-Tr will be in Auto Alternator turn on mode.

I need to parallel two Orion's and their control inputs too. A time delay relay will open the H&L contacts 5 minutes after the Ignition signal goes active to allow the engine to warm up before loading the alternator. The Victron manual doesn't state whether the H&L control inputs on one Orion-Tr can be connected to the respective H&L control inputs on the other Orion so that a single SPDT relay will control both...

Been considering adding a 2nd parallel Orion Smart DC-DC here in my unit, I have one 12-12 30A unit installed now to charge my LiFEPO4 battery bank from the chassis. Is this TRUE? That they might have issues due to auto engine run detection "lag"? I assumed they could operate independently and if one detected engine on with a delay/lag that it would simply join in charging and not be an issue? Now the question about how they decide which charge mode to be in; bulk, absorption or float I am not sure about how that part works???

To correct some misinformation.

If H and L are junpered together, the Orion is ON. They're supplied this way. And use voltage sensing to decide whether or not to charge.

Cigarette lighter sockets may be permanently ON, or may be switched with ignition. Check on the vehicle.

If you're considering a single wire from a switched source, say to H, remember the Orion uses this as voltage sensing, not as input power. So current draw is negligible. Unless you also connect DC in to the same point.

Voltage sensing for smart alternators may need you to adjust the Orion configuration. As it's in operation normally to prevent the input battery from excessive discharge, think carefully before overriding it. In most cases you must use one of the HL options to switch the unit.