Victron Multiplus-II 12 3000 Inverter Charger Wiring Diagram

Victron Multiplus-II 12 3000 Inverter Charger Wiring Diagram

Victron Multiplus-II 12 3000 Inverter Charger Wiring Diagram

5/5 (1👤)
☀️ Solar & Batteries 🧮 3 schematics
★Rate It★
🧮 Diagram 🖨️ Print 📖 Instructions 🛠️ Troubleshooting 💬 FAQs

How many stars do you give this diagram?

Power connections

AC, ground and battery terminals, left to right as on the unit.

Power connections
MULTIPLUS-II 12/3000/120 · SERVICE PANEL REMOVEDCONTROL (SEE TAB 2)AUX RELAYTRICKLESWITCH12 V BATTERYAC-OUT-1NN⏚PELLRCCD + 50 ALOADS(OUTPUT 1)AC-OUT-2NN⏚PELLRCCD + 32 ANON-CRITICALLOADSAC-INNN⏚PELL50 A BREAKERGRID ORGENERATORPE M6CHASSIS / GROUND+ M8400 A FUSEDISCONNECT− M8

Terminals and components · 6

  • AC-IN
  • AC-OUT-1
  • AC-OUT-2
  • Ground
  • Battery +
  • Battery −

About This Diagram

These diagrams are redrawn from pages 13–16 and 31–34 of the Victron Multiplus-II 12 3000 Inverter Charger manual, and we offer them completely free and in English. We have also categorized it in the Inverters (Solar & Batteries) section on Diagramverse, and it has been rated by 1 user with an average rating of 5.0. If you have any specific questions about the Victron Multiplus-II 12 3000 Inverter Charger Wiring Diagram, we suggest checking the Frequently Asked Questions (FAQs) section.

Printable Victron Multiplus-II 12 3000 Wiring Diagrams

Complete

1 / 3
Victron Multiplus-II 12 3000 Inverter Charger Wiring Diagram – Complete
Victron Multiplus-II 12 3000 Inverter Charger Wiring Diagram – Control
Victron Multiplus-II 12 3000 Inverter Charger Wiring Diagram – Block diagram

Wiring Instructions

Before you start

The Victron Multiplus-II 12 3000 diagram has three tabs. Complete shows the power connections that every installation needs. Control shows the optional signal terminals. Block diagram shows how the internal relays route power. This guide covers the 12 V, 3000 VA, 120 V model (12/3000/120). Check the rating label on your unit first: the 24 V, 48 V, 4k and 5k versions need different fuses and cable sizes.

A qualified electrician should install this unit. Fixed 120 V wiring must follow the NEC (ANSI/NFPA 70) or the Canadian Electrical Code, and most jurisdictions require a permit. You will need:

  • A torque wrench with an insulated box spanner for the M8 battery nuts, and a screwdriver for the AC terminal blocks.
  • Copper cable rated 90 °C (194 °F). For the battery, use two AWG 1/0 per pole on runs up to 16 ft, or two AWG 2/0 per pole on runs of 16 to 33 ft.
  • A 400 A DC fuse, and a battery disconnect rated for at least that fuse current.
  • Three-wire AC cable: AWG 6 minimum for AC-IN and AC-OUT-1, and AWG 10 for AC-OUT-2. Fit ferrules, with the wire stripped 0.7 inch (18 mm).
  • A 50 A breaker for the input. For AC-OUT-1, a 50 A breaker plus a UL 943 residual current device. For AC-OUT-2, a breaker of 32 A maximum plus a UL 943 residual current device.
  • A ground conductor of at least 4 mm² for the PE M6 stud.

Mount the unit on a solid wall in a dry, well-ventilated spot, as close to the battery as practical. Never mount it above a battery, and keep flammable materials away. Before you touch any terminal, set the front switch to off (middle position), open the AC supply breaker and remove the battery fuse.

Step-by-step wiring

  1. Remove the two screws at the bottom of the enclosure and take off the service panel.
  2. Connect the Primary ground to the PE M6 stud. In a vehicle or boat, bond it to the chassis, hull or grounding plate. Unplugging shore power also disconnects the input ground, so the case needs its own ground path.
  3. Run the battery cables while the fuse and disconnect are open. Stack each connection on the + M8 and − M8 bolts in this order: cable lug, flat washer, lock washer, nut. Torque each nut to 12 Nm. Put the 400 A fuse and the disconnect in the positive line. Keep the positive and negative cables the same size, and do not run them in a closed conduit.
  4. Wire AC-IN from the grid or generator breaker: N, PE, L, from left to right. Never swap neutral and phase. Tighten the terminals to no more than 2 Nm.
  5. Wire AC-OUT-1 to your critical-loads panel through its residual current device and breaker, again in the order N, PE, L.
  6. Wire loads that must never run from the battery, such as a water heater or air conditioner, to AC-OUT-2. Feed them through their own residual current device and a breaker of 32 A maximum.
  7. Add any optional control wiring from the Control tab. Connect a remote switch across Remote. Connect the temperature sensor to 9 · 10 and mount it on the battery negative. Run AWG 18 voltage sense wires from 11 · 12 straight to the battery posts. If you use lithium, connect the BMS to the aux inputs. To charge a starter battery, connect Trickle to its positive. Both batteries must share a negative, on the load side of any shunt.
  8. If you use an external current sensor, remove the factory bridge between INT and COM. Then connect the red wire to EXT and the white wire to COM.
  9. Check every terminal, refit the service panel and insert the battery fuse.

Testing and start-up

Before you close the disconnect, check polarity on the cable ends with your meter rather than trusting wire color. The battery voltage should sit well inside the 9.5 to 17 V input range. Close the disconnect and set the switch to on with no AC connected. The inverter LED should light. You should read about 120 V between L and N at AC-OUT-1, and AC-OUT-2 should stay dead.

Now close the input breaker. With 90 to 140 VAC at AC-IN, the unit synchronizes and the mains on LED lights. The bulk, absorption or float LED shows the charge stage. AC-OUT-2 comes back after about 2 minutes. Press the test button on each residual current device twice: once on grid power and once on inverter power. This confirms that the internal ground relay bonds neutral correctly.

The default charge voltages are 14.4 V absorption and 13.8 V float, which suit gel and AGM batteries. If your battery needs other values, change the settings with VictronConnect or VEConfigure. Connect through an MK3-USB interface on a VE.Bus port, and disconnect the AC input while you configure.

Safety notes

  • A 12 V bank can deliver enormous short-circuit current. Remove rings and watches, use insulated tools, and never let a wrench bridge the battery posts.
  • The battery keeps the unit powered, so dangerous voltage can remain on the AC terminals after you switch it off. Open both the battery disconnect and the AC breaker before any work.
  • The unit is class I, so its ground must never be interrupted. If the grounding is damaged, take the unit out of service.
  • Lead-acid batteries vent explosive gas. Keep sparks and flames away, and ventilate the battery space.
  • You cannot replace the internal fuses yourself. If you suspect one has blown, take the unit to a service center.

Troubleshooting

Symptom Probable Cause What to Check
Loads on the second output go dead during a power outage Normal behavior: AC-OUT-2 disconnects whenever the unit runs on battery Move loads that must stay on during outages to AC-OUT-1. After AC returns, AC-OUT-2 should come back in about 2 minutes.
Nothing happens when I switch the unit on Battery fuse blown, disconnect open, or battery voltage out of range Measure between the + M8 and − M8 studs. You should read 9.5 to 17 V. If you don't, check the 400 A fuse, the disconnect and the cable lugs.
The cable lugs or battery cables get hot under load Undersized cable or loose connection Use two AWG 1/0 per pole (two AWG 2/0 for runs over 16 ft). Make sure each lug sits directly on the stud with the washers on top, and torque to 12 Nm.
The low battery and overload LEDs flash at the same time Ripple voltage on the DC connection is above 1.5 Vrms Check for loose battery terminals and undersized or overlong cables. Use shorter or thicker cables, or more battery capacity.
The grid or generator is connected but the unit won't switch over or charge Input breaker tripped, or input voltage or frequency outside the accepted range Measure L to N at AC-IN. It must be within the set range (90 to 140 VAC by default). Clear any overload or short on the outputs and reset the input breaker.
On generator, the unit keeps dropping back to inverter or barely charges Distorted or unstable generator output Turn off the UPS feature. Turn on WeakAC and the dynamic current limiter. With large AVR generators, raise the lower input voltage limit to 110 VAC.
The output residual current device trips as soon as the grid connects Neutral and phase swapped, or an extra neutral-to-ground bond downstream Check the N, PE, L order at AC-IN and AC-OUT-1. Remove any neutral-to-ground bond in the load panel; the internal ground relay provides the bond on inverter power.
The bulk and absorption LEDs flash together Voltage sense error: the sensed voltage differs from the stud voltage by more than 7 V Check the sense wires on 11 · 12: correct polarity, firm connections, and both wires landed on the battery posts.
The absorption and float LEDs flash together Temperature sensor miswired or defective Check the sensor on 9 · 10 and make sure it is mounted on the battery negative terminal.
Charging drops to zero as soon as absorption starts Battery above 50 °C, or a defective temperature sensor Disconnect the sensor. If charging works after about 1 minute, replace the sensor. Otherwise cool the battery and check it for a shorted cell.
My remote on/off switch does nothing Front switch not set to on, or a second remote device is connected Set the front switch to on. Make sure the switch shorts the two Remote terminals, and that only one remote device (switch or panel) is connected.

Frequently Asked Questions (FAQs)


What battery fuse and cable size does the 12/3000 model need?
Use a 400 A DC fuse and a disconnect rated for at least that current. For battery runs up to 16 ft, use two AWG 1/0 copper cables per pole. For runs of 16 to 33 ft, use two AWG 2/0 per pole. The cable should be rated 90 °C (194 °F), the same size on positive and negative, and not run in a closed conduit. The recommended battery capacity for this model is 400 to 1200 Ah.

What is the difference between AC-OUT-1 and AC-OUT-2?
AC-OUT-1 is the uninterrupted output: it runs from the grid or generator and switches to the inverter in less than 20 milliseconds if the input fails. AC-OUT-2 is live only while AC is present on the input. It shuts off on battery power and returns about 2 minutes after AC comes back. Use AC-OUT-2, rated 32 A maximum, for heavy loads such as water heaters that should never drain the battery.

Can I connect the MultiPlus-II directly to my vehicle's electrical system?
No. This unit is not suitable for direct connection to a vehicle's electrical system. It must connect to a DC system with its own dedicated house or service battery, the proper fuse and correctly sized cables. If you also want to keep the engine's starter battery topped up, use the Trickle output. It charges at up to 4 A from the house battery, and both batteries must share a common negative.

Can I use lithium batteries with this inverter charger?
Yes, as long as the battery has a battery management system that monitors and controls charging. With Victron Lithium Smart batteries, use a VE.Bus BMS V2 or a Lynx Smart BMS. For other brands, check Victron's battery compatibility list for wiring and settings. The two aux inputs on terminals 5 to 8 can communicate with a BMS. The default charge settings are for gel and AGM, so you must reconfigure the charge curve for lithium.

Do I need a neutral-to-ground bond on the output?
No, the unit handles it. An internal ground relay bonds the output neutral to the chassis whenever no external AC is present, so residual current devices on the outputs keep working on inverter power. When AC arrives, the relay opens before the input relay closes, and the bond comes from the grid. Systems such as split-phase with an autotransformer may need an external ground relay on terminals 3 and 4. Disable the internal relay first.

How much current can AC-OUT-1 supply with PowerAssist?
Up to about 75 A. The input passes up to 50 A, and PowerAssist can add up to 3 kVA, about 25 A at 120 V, from the battery during peaks. Size the AC-OUT-1 residual current device, breaker and cable for the load you actually expect. Set the AC input current limit to match your shore or generator supply so the unit doesn't overload it.

What type of residual current device can I use on the outputs?
Type A devices are fine. The low-frequency isolating transformer prevents any DC current from reaching the AC ports. Each output needs a UL 943 compliant residual current device in series, together with a fuse or breaker sized for the load. AC-OUT-2 is limited to a 32 A breaker maximum. Blue Sea Systems GFCI breakers, PN 309X or 310X, are a suitable choice.

Can I parallel several units or build a 240 V split-phase system?
Yes. You can connect up to six identical units in parallel. All of them must share the same battery and use DC cables of equal length and size. Two units of the same model can provide 240 V split-phase, and three units can form a three-phase wye system, though not delta. Link the units with direct RJ45 UTP cables on the VE.Bus ports, without splitter boxes, and connect the negative battery cables before the data cables.

Can the MultiPlus-II start and stop a generator automatically?
Yes. The programmable relay on the NO · NC · COM terminals can work as a generator start/stop contact instead of its default alarm function. Its rating is 120 V / 4 A AC, or 4 A up to 35 VDC. The built-in battery monitor can trigger the start by state of charge, battery voltage or load level. You set this up with VEConfigure or VictronConnect.

Do I need the temperature sensor and voltage sense wires?
Neither is mandatory, but both improve charging. The temperature sensor lowers the charge voltage as the battery warms, which is especially important for maintenance-free batteries that can dry out if overcharged. Mount it on the battery negative terminal. The voltage sense wires (AWG 18, on terminals 11 and 12) measure voltage at the battery and make up for up to 1 V of drop on each cable. They help most on long battery runs.

Related Product Diagrams

Go up