Victron Orion-Tr Smart 12/12-30

This is the isolated Orion-Tr Smart 12/12-30A (360 W), Victron part ORI121236120, the model most "Orion TR Smart 30A wiring diagram" searches mean. Victron also sells a non-isolated 12/12-30 that shares one negative between input and output; this page models the isolated one, whose input and output returns are separate. The product family page rates it at 30 A continuous at 40 °C, a 40 A peak for 10 seconds, about 87 % efficiency and a 10–17 V input.

IN + comes from the starter battery through a fuse at that battery; OUT + charges the house or leisure battery through a fuse at the house battery. IN − and OUT − are two separate returns on this isolated model, one to each bank. Victron's manual calls for a 60 A fuse on the input side, and the installation section carries the full cable-and-fuse table by run length; the screw terminals accept up to 16 mm² (6 AWG). Those fuses protect the cable, and belong at the battery end of each run.

The technical reference above sizes the example run with Crimp's engine from the catalog's terminal ratings, and the starter lets you change the lengths. The manual's table is the floor.

• Heat is the defining constraint of this model. At 87 % efficiency roughly an eighth of the throughput becomes heat, and the datasheet rates the 30 A only up to 40 °C, derating about 3 % per degree above it. A closed locker or an engine bay in summer means less than 30 A. Mount it fins-vertical with air moving past; IP43 only applies with the terminals pointing down.
• Engine detection reads the input voltage. Smart alternators on Euro 5 and Euro 6 vehicles drop the starter side below the detection threshold once that battery is full, and the charger stops. The manual's engine shutdown detection section describes the override from an ignition-switched or D+ feed on the remote connector. Turning detection off in VictronConnect leaves only the input lockout voltage to protect the starter battery.
• The alternator sees more than 30 A. Output current times output voltage, divided by efficiency and the lower input voltage, is what the starter side supplies, so the input cable, its fuse and the alternator's spare capacity are all budgeted above the nameplate.
• VictronConnect does not show current. The Orion-Tr Smart range has no current sensor and no VE.Direct port; the non-isolated datasheet prints both as notes. A shunt on the house bank is how you see the amps.
• Units can be paralleled, without limit per the datasheet, which is how installers get past 30 A without moving to a different product line.

• "It gets hot and folds back." The recurring report is a unit that delivers its 30 A cold and settles to roughly 20–25 A once the case is hot in an enclosed compartment; a fan over the fins or relocating it into moving air restores the output. See this thread, this one and the T6 forum. Victron's answer in those threads is that the derating is by design and the fix is airflow.
• Smart alternators stop it charging. Owners of Fiat Ducato, VW Transporter and Ford Transit vans describe charging that cuts out under "engine shutdown detected"; the fix agreed in this thread and on MotorhomeFun is the ignition or D+ feed to the remote connector, not disabling detection.
• Fuse placement is asked and answered often. The isolated fuse placement thread and the fusing thread settle on a fuse at each battery, sized for the cable.
• New builds are steered to the Orion XS. Installers and resellers now recommend the XS 12/12-50 where isolation is not required, for its efficiency, size and current readout; see this comparison and this Victron Community thread. The isolated Orion-Tr Smart remains the pick when the banks must not share a negative.

• Check the vehicle side with the DC-DC charger size tool, which separates output rating from input draw and alternator headroom, and size the run with the wire size calculator.
• Compare the Orion XS 12/12-50A when isolation is not needed, or the Orion-Tr Smart 12/12-18 for a smaller bank or alternator.
• Add a SmartShunt 500A or BMV-712 Smart to see the charge current.
• Open a complete dual-battery B2B example or the campervan solar and alternator diagram; each opens in Crimp. Converting the house bank? Start with the lead-acid to LiFePO4 guide.