How to Install a Victron Orion XS: Wiring and Settings

This guide shows how to install a Victron Orion XS 12/12-50A DC-DC charger, so your alternator charges your house battery while you drive. The Orion XS sits between the starter battery and the house battery. It gives the house battery a proper charge, even from a smart alternator, without draining the starter battery.

Electrical work can be dangerous: follow the manual, fuse and size every cable correctly, and use a licensed electrician for anything connected to household wiring.

Mobile Solar Consulting’s step-by-step Orion XS install.

Parts You Need to Install a Victron Orion XS

Item	From the Orion XS manual
Fuse at each battery	60-70A, one near the starter battery and one near the house battery
Cable, runs under 5m	16mm² / 6AWG minimum
Cable, runs of 5-10m	4AWG (21.2mm²) minimum
Cable type	Flexible multi-stranded copper (Class 5 / UL Class I)
Terminal torque	5.6Nm for 4AWG, 4.5Nm for 6AWG
Largest cable accepted	4AWG

Step-by-Step Wiring

Plan the mounting spot. The Orion XS gets hot, so mount it on a non-flammable surface with free airflow. The 50A model is IP65, so it tolerates damp areas. The 70A model is IP20, for dry indoor spaces only.
Disable the unit first. Victron’s procedure is to remove the remote on/off wire bridge before connecting power. It’s re-fitted last.
Run the negative cables as shown in the manual’s wiring diagram, using the same size cable as the positives.
Run the input positive from the starter battery through a 60-70A fuse to the Orion’s input terminal.
Run the output positive from the Orion’s output terminal through a 60-70A fuse to the house battery.
Tighten to torque. Victron says to hold the specified torque for at least 5 seconds. Hexagonal ferrule crimps fit 16mm² cable; square crimps won’t.
Re-connect remote on/off. Use the wire bridge, or wire a switch or a lithium BMS “allow-to-charge” contact to the remote terminal.

Set It Up in VictronConnect

Choose the battery preset, such as lithium, or enter custom absorption and float voltages.
Set the charge current between 1A and 50A in 0.1A steps. Lower it if your alternator is small.
Check engine shutdown detection. The default works with most standard and smart alternators. If your vehicle’s voltage doesn’t move enough, Victron supports an external engine-running signal: more than 8V on the L-pin turns charging on.
Optional: use VE.Smart Networking to take battery voltage, temperature and current from a SmartShunt or BMV, or connect VE.Direct to a GX device.

Common Mistakes

Fusing only one end. Fuse both battery connections.
Cable that’s too thin for the run length. Voltage drop reduces charging and triggers input lock-out.

Want the source figures? The Orion XS page on Victron’s site has the datasheet.

Choosing a Mounting Spot by Vehicle Type

Sprinter-style van: under the passenger seat base or on the wall beside the house battery, keeping the output cable short.
Pickup with a truck camper: inside the camper near the house battery, with the long run on the input side from the engine bay.
Small RV: in a dry storage bay close to the house battery bank.
Damp locations: the IP65 50A model tolerates damp spots, while the 70A model is IP20 for dry indoor spaces.

Wherever it goes, leave clear space for airflow and keep it on a non-flammable surface.

Worked Example: A Typical Van Install

A van with the starter battery under the hood and a 200Ah lithium house battery under the bed, 4m apart:

Cable: 6AWG minimum for runs under 5m. Using 4AWG cuts voltage drop further for not much extra cost (suggestion).
Fuses: 60–70A at the starter battery and at the house battery.
Settings: lithium preset, current set to 40A to start, then raised to 50A once you’ve watched the alternator over a few drives (example approach).
Result: about 40–50Ah per hour of driving into the house battery (estimate).

Testing After the Install

With the engine off, check that the Orion XS shows “off” or “engine off” in VictronConnect.
Start the engine. Within a short time, the charger should begin charging as it detects the alternator voltage.
Watch input voltage and output current. If input voltage sags close to the shutdown setting, check cable size and connections.
Turn the engine off. The charger should stop after it detects engine shutdown.
Feel the cable lugs after 20 minutes of charging. Warm is fine, hot points to a loose or poorly crimped connection.

Wiring the Remote Input to a BMS

Many lithium batteries offer an “allow-to-charge” signal. Wiring it to the Orion XS remote terminal lets the battery stop charging when it’s full or too cold. Follow the manual’s diagram for the remote H and L terminals so the signal works in the right direction.

Using the L-Pin Engine Signal

On vehicles where alternator voltage doesn’t change enough to detect engine running, wire an ignition-switched signal to the L-pin. More than 8V turns charging on. This gives the most reliable start and stop on smart alternators.

Adding Monitoring

VE.Smart Networking: join the Orion XS to a SmartShunt or BMV so it uses accurate battery voltage, current and temperature.
GX device: connect VE.Direct to a Cerbo GX to see alternator charging in VRM alongside solar and shore power.

Maintenance Checks

Every few months, check terminal torque, look for chafing where cables pass through panels, and confirm both fuses are seated and clean. On vans that see rough roads, a quick check after long trips keeps connections tight.

Keeping Cables Tidy and Protected

Run cables through grommets wherever they pass through metal, and secure them every 300mm or so with cable clamps (typical practice). Use split loom or conduit in the engine bay. Label both ends of each cable so future work is quicker.

FAQ

Do I need an ignition wire?

Usually not. The Orion XS detects when the engine is running from the alternator voltage.

Can I add a second Orion XS?

Yes. Victron says any number of units can run in parallel.

Can it charge from a 24V vehicle?

The 12/12-50A takes a 9-17V input. Use the Orion XS 1400 for 24V input.

How long does the install take?

For most vans, a few hours, mostly spent routing cables. Planning the cable route first saves the most time.

Can I mount the Orion XS in the engine bay?

Victron rates the 50A model IP65, but engine bays get very hot. A cooler location near the house battery is usually better.

Sources: Orion XS DC-DC battery charger manual and datasheet (victronenergy.com); Mobile Solar Consulting, “How to Install Victron Orion XS & XS 1400”; Explorist Life, “The New 50A Orion DC DC Charger”.