Victron Orion XS DC-DC Charger: Complete Install Guide

The Victron Orion XS is our top-rated DC-DC charger for UK campervans (see the full best DC-DC charger roundup). This guide walks you through the complete installation process — from planning your cable route to configuring the VictronConnect app.

Whether you are building your first campervan or upgrading from a split charge relay, this install is well within DIY ability. You will need basic tools, correct cables, and about 3-4 hours. If you are still deciding between a DC-DC charger and a relay, read our comparison guide first.

Use the VanPower calculator to confirm the right charger size and generate a wiring diagram for your specific build before starting.

What You Will Need

The Charger

• Victron Orion XS 12/12-30A (most common) — around £230-£260
• Also available in 20A (£180-£210) and 50A (£320-£360)

Cables

Cable sizing depends on the charger rating and cable length. For the 30A model with a typical run of 4-6 metres (front to rear of a panel van):

Use tri-rated cable (rated for automotive and marine use) with flexible stranded copper conductors. For a detailed explanation, see our cable sizing guide.

You need:

• Positive cable from starter battery to charger input
• Positive cable from charger output to leisure battery
• Negative cables (same gauge) or chassis earthing

Fuses and Fuse Holders

• Input fuse: MEGA or MIDI fuse at the starter battery end — 40A for a 30A charger (fuse should be slightly above charger rating to avoid nuisance trips, but sized to protect the cable)
• Output fuse: MEGA or MIDI fuse at the leisure battery end — 40A for a 30A charger
• Two fuse holders (bolt-down MEGA or MIDI type)

Other Components

• Cable lugs (crimped, not soldered) — M8 ring terminals for battery connections
• Heat shrink tubing
• Cable ties and P-clips for routing
• Self-tapping screws or bolts for mounting the charger
• Split loom or conduit for cable protection where it passes through bulkheads

Tools

• Crimping tool (ratchet type recommended for large lugs)
• Wire strippers
• Multimeter
• Drill with step bit (for bulkhead grommet holes)
• Spanners for battery terminals
• Heat gun for heat shrink
• Smartphone with VictronConnect app installed

Step 1: Plan Your Cable Route

Before cutting any cable, trace the path from your starter battery to the charger mounting location, and from the charger to your leisure battery.

Typical Route in a Panel Van

In a Ford Transit, VW Crafter, or Fiat Ducato-based conversion:

1. The starter battery is in the engine bay (usually passenger side).
2. Cable passes through the bulkhead via an existing grommet or a new drilled hole.
3. Cable runs along the floor or behind interior panels to the rear of the van.
4. The charger mounts near the leisure battery in the rear electrical area.

Key Routing Considerations

• Avoid heat sources: Keep cables away from exhaust components, diesel heater pipes, and engine hot spots.
• Protect cable penetrations: Use rubber grommets wherever cables pass through metal panels. A bare cable rubbing against sheet metal will eventually chafe through the insulation and short to chassis.
• Keep it accessible: Route cables where you can inspect them later. Under the floor is fine if accessible; inside sealed cavities is not ideal.
• Minimise length: Shorter cables mean less voltage drop and thinner cable requirements. Plan the most direct route possible.

Step 2: Mount the Charger

The Victron Orion XS has two mounting tabs and can be mounted in any orientation (horizontal, vertical, or even upside down — it is fanless and does not care).

Mounting Location Requirements

• Ventilation: The charger generates heat under full load (around 30-40W of waste heat at 30A). Mount it where air can circulate around it. Do not enclose it in an airtight box.
• Accessibility: You need to reach the cable terminals and see the status LEDs. Mount it where you can access it for maintenance.
• Proximity to leisure battery: Mount the charger as close to the leisure battery as practical. The output cable carries high current and should be short.
• Vibration: Use all mounting holes. The charger weighs just over 1kg, but van vibration is relentless. Use self-locking nuts or thread-locking compound.

Typical Mounting Spots

• On the side wall of your electrical cabinet, near the leisure battery
• Under a bench seat, on the partition wall
• In a dedicated electrical area behind a kick panel

Drill pilot holes, secure with M5 bolts or appropriate self-tapping screws, and ensure the unit is firm with no rattle.

Step 3: Run and Connect the Input Cable (Starter Battery Side)

At the Starter Battery

1. Fit the input fuse holder within 300mm of the starter battery positive terminal. This fuse protects the cable in case of a short circuit between the engine bay and the rear of the van.
2. Crimp an M8 ring lug onto the cable end using a ratchet crimper. Tug-test it firmly — it must not pull off.
3. Apply heat shrink over the crimped connection for insulation and strain relief.
4. Connect to the starter battery positive terminal. Most starter batteries have a bolt-on terminal or a distribution post.

Cable Run

1. Feed the cable through the bulkhead grommet.
2. Secure with P-clips every 300-500mm along the route.
3. Use split loom where the cable passes near anything sharp or hot.
4. Leave a small service loop at each end for future maintenance.

At the Charger

1. Strip the cable end to match the charger terminal requirements.
2. Crimp an appropriate lug if the charger uses bolt terminals, or use a bootlace ferrule for cage clamp terminals.
3. Connect to the charger's INPUT positive terminal (marked with a battery icon and "+" or "BAT IN").

Step 4: Run and Connect the Output Cable (Leisure Battery Side)

This is typically a short run — ideally under 1 metre if the charger is mounted near the leisure battery.

1. Fit the output fuse holder within 300mm of the leisure battery positive terminal.
2. Crimp and connect to the charger's OUTPUT positive terminal.
3. Run the cable to the leisure battery via the fuse holder.
4. Connect to the leisure battery positive terminal (or your positive busbar if you have one).

Step 5: Connect the Negative (Ground) Cables

You have two options:

Option A: Direct Negative Cables (Recommended)

Run a negative cable from the charger's input negative terminal back to the starter battery negative terminal (or a solid chassis earth point near the starter battery). Run a second negative cable from the charger's output negative terminal to the leisure battery negative terminal.

This is the most reliable method and avoids any issues with chassis earth resistance.

Option B: Chassis Earthing

Connect both the input and output negative terminals to the vehicle chassis via short, thick cables and clean, bare-metal mounting points. This saves cable but depends on good chassis connections.

Step 6: Engine Detection

The Victron Orion XS can detect engine running in two ways:

Voltage Sensing (Default)

The charger monitors the input voltage. When it rises above the engine-running threshold (configurable in the app, default around 13.0V), it starts charging. When voltage drops (engine off), it stops.

This works well with conventional alternators but can be unreliable with smart alternators that drop voltage during driving.

Ignition Wire (Recommended for Smart Alternators)

Run a thin wire (0.5-1mm²) from the charger's "remote on/off" terminal to a 12V source that is only live when the ignition is on. Good sources include:

• The ignition-switched fuse box in the cab
• A relay triggered by the ignition
• The OBD port 12V supply (always on with ignition)

This method is reliable regardless of alternator behaviour.

Step 7: Double-Check Everything

Before reconnecting batteries:

1. Verify polarity — use a multimeter to confirm positive and negative are correct at every connection.
2. Check all crimps — tug-test every lug.
3. Verify fuses are installed — and are the correct rating.
4. Check cable routing — no chafing, no contact with hot components, all grommets in place.
5. Verify the charger terminals — input and output are not swapped.

Step 8: Power On and Configure

1. Reconnect the leisure battery negative terminal first, then the starter battery negative terminal.
2. Reconnect the starter battery positive, then the leisure battery positive.
3. The charger should power up and show a standby LED.
4. Open the VictronConnect app on your phone and connect via Bluetooth.

App Configuration

In the VictronConnect app, set the following:

1. Battery type: Select LiFePO4, AGM, GEL, or custom. For Fogstar Drift batteries, use the LiFePO4 preset or enter the manufacturer's recommended voltages.
2. Charge current: Set to the charger's rated current (30A for the 30A model) or lower if you want to limit alternator load.
3. Engine detection: Set to "Voltage" or "Remote input" depending on your wiring.
4. Smart alternator mode: Enable this if your van has a smart alternator. It limits initial inrush current and manages current ramp-up.

Step 9: Test

1. Start the engine.
2. Open VictronConnect and verify the charger enters bulk charging mode.
3. Monitor input voltage, output voltage, and charging current.
4. Check that the charger shuts down when you turn off the engine.
5. Feel the charger after 15-20 minutes of charging — it should be warm but not too hot to touch.

Troubleshooting

Charger Does Not Start When Engine Is Running

• Check engine detection method. If using voltage sensing, the starter battery voltage may not be rising high enough (common with smart alternators). Switch to ignition wire detection.
• Verify input fuse is intact.
• Check input cable connections — loose crimps are the most common issue.

Charger Starts but Shows Low Current

• Check cable gauge — undersized cables cause voltage drop, which the charger compensates for by reducing current.
• Check the leisure battery state of charge — if it is nearly full, the charger naturally reduces current during absorption and float stages.
• Verify the charge current setting in the app has not been accidentally limited.

Charger Gets Very Hot

• The Orion XS has thermal derating — it reduces output if it overheats. Ensure adequate ventilation around the unit.
• Check that the mounting location allows airflow on all sides.
• In summer, ambient temperatures in a van can exceed 40C, which limits the charger's ability to dissipate heat.

Frequently Asked Questions

Can I install the Victron Orion XS myself?

Yes. This is a 12V DC installation with no mains voltage involved. If you are comfortable with basic automotive electrics — fitting a car stereo, adding spotlights — you can install a DC-DC charger. The critical points are correct cable sizing, proper crimping, and fuse protection.

Where should I mount the charger?

As close to the leisure battery as practical, in a ventilated location. The most common spot is on the wall of the electrical cabinet or under a bench seat near the battery. Keep the output cable short (under 1m ideally).

Do I need to run an ignition wire?

It is recommended for vans with smart alternators. Without it, the charger relies on voltage sensing, which can be unreliable when the alternator drops voltage during normal driving. An ignition wire guarantees reliable engine detection.

Can I mount the Orion XS in any orientation?

Yes. It is fanless with passive cooling, so orientation does not matter. Horizontal, vertical, upside down — all are fine.

How do I know if it is working correctly?

Open the VictronConnect app while driving. You should see the charger in "Bulk" mode with current flowing at or near its rated output (30A for the 30A model). The input voltage should show your alternator voltage, and the output voltage should show the correct charging voltage for your battery type.