MultiPlus-II 12V/24V/48V 3kVA 120V

5. Configuration

In this section:

This section is intended mainly for stand-alone applications.


Settings may only be changed by a qualified electrical engineer.

Read the instructions thoroughly before implementing changes.

During setting of the charger, the AC input must be removed.

5.1. Standard settings: ready for use

On delivery, the MultiPlus-II is set to standard factory values. In general, these settings are suitable for single-unit operation.


Possibly, the standard battery charging voltage is not suitable for your batteries! Refer to the manufacturer's documentation, or to your battery supplier!

Standard MultiPlus-II factory settings

Inverter frequency

60 Hz

Input frequency range

45 – 65 Hz

Input voltage range

90 - 140 VAC

Inverter voltage

120 VAC

Stand-alone / parallel / 3-phase


AES (Automatic Economy Switch)


Ground relay


Charger on/ off


Battery charge curve

four-stage adaptive with BatterySafe mode

Charging current

100% of the maximum charging current

Battery type

Victron Gel Deep Discharge (also suitable for Victron AGM Deep Discharge)

Automatic equalisation charging


Absorption voltage

14.4 V / 28.8 V / 57.6 V

Absorption time

up to 8 hours (depending on bulk time)

Float voltage

13.8 V / 27.6 V / 55.2 V

Storage voltage

13.2 V / 26.4 V / 52.8 V (not adjustable)

Repeated absorption time

1 hour

Absorption repeat interval

7 days

Bulk protection


AC input current limit

50A (= adjustable current limit for PowerControl and PowerAssist functions)

UPS feature


Dynamic current limiter






Programmable relay

alarm function

Auxiliary output

16 A



5.2. Explanation of settings

Settings that are not self-explanatory are described briefly below. For further information, please refer to the help files in the software configuration programs (see Section 5.3).

Inverter frequency

Output frequency if no AC is present at the input.

Adjustability: 50 Hz; 60 Hz

Input frequency range

Input frequency range accepted by the MultiPlus-II. The MultiPlus-II synchronises within this range with the AC input frequency. The output frequency is then equal to the input frequency.

Adjustability: 45 – 65 Hz; 45 – 55 Hz; 55 – 65 Hz

Input voltage range

Voltage range accepted by the MultiPlus-II. The MultiPlus-II synchronises within this range with the AC input. The output voltage is then equal to the input voltage.


Lower limit: 90 – 120 V

Upper limit: 120 – 140 V


The standard lower limit setting of 90V/180V is intended for connection to a weak mains supply, or to a generator with unstable AC output. This setting may result in a system shut down when connected to a ‘brushless, self excited, externally voltage regulated, synchronous AC generator’ (synchronous AVR generator). Most generators rated at 10kVA or more are synchronous AVR generators. The shut down is initiated when the generator is stopped and revs down while the AVR simultaneously ‘tries’ to keep the output voltage of the generator at 120V/230V.

The solution is to increase the lower limit setting to 110/220VAC (the output of AVR generators is generally very stable), or to disconnect the MultiPlus-II from the generator when a generator stop signal is given (with help of an AC contactor installed in series with the generator).

Inverter voltage

Output voltage of the MultiPlus-II in battery operation.

Adjustability: 110 – 130 V

Stand-alone / parallel operation / 2-3 phase setting

Using several devices, it is possible to:

  • increase total inverter power (several devices in parallel)

  • create a split-phase system with a separate autotransformer: see VE autotransformer datasheet and manual.

  • create a 3-phase system.

The standard product settings are for standalone operation. For parallel, three-phase or split phase operation see section 5.3.

AES (Automatic Economy Switch)

If this setting is turned ‘on’, the power consumption in no-load operation and with low loads is decreased by approx. 20%, by slightly 'narrowing' the sinusoidal voltage. Applicable in stand-alone configuration only.

Search Mode

Instead of the AES mode, the search mode can also be chosen. If search mode is ‘on’, the power consumption in no-load operation is decreased by approx. 70%. In this mode the MultiPlus-II, when operating in inverter mode, is switched off in case of no load or very low load, and switches on every two seconds for a short period. If the output current exceeds a set level, the inverter will continue to operate. If not, the inverter will shut down again.

The Search Mode ‘shut down’ and ‘remain on’ load levels can be set with VEConfigure.

The standard settings are:

Shut down: 40 Watt (linear load)

Turn on: 100 Watt (linear load)

Ground relay (see appendix B)

With this relay, the neutral conductor of the AC output is grounded to the chassis when the back feed safety relays are open.

This ensures the correct operation of earth leakage circuit breakers in the output. If required an external ground relay can be connected (for a split-phase system with a separate autotransformer). See appendix A.

Battery charge algorithm

The standard setting is ‘Four-stage adaptive with BatterySafe mode’. See Section 2 for a description.

This is the recommended charge algorithm for lead acid batteries. See the help files in the software configuration programs for other features.

Battery type

The standard setting is the most suitable for Victron Gel Deep Discharge, Gel Exide A200, and tubular plate stationary batteries (OPzS).

This setting can also be used for many other batteries: e.g. Victron AGM Deep Discharge and other AGM batteries, and many types of flat-plate flooded batteries.

With VEConfigure the charge algorithm can be adjusted to charge any battery type (Nickel Cadmium batteries, Lithium-ion batteries)

Absorption time

In case of the standard-setting ‘Four-stage adaptive with BatterySafe mode’ the absortion time depends on the bulk time (adaptive charge curve), so that the battery is optimally charged.

Automatic equalisation charging

This setting is intended for flooded tubular plate traction or OPzS batteries. During absorption the voltage limit increases to 2,83V/cell (34V for a 24V battery) once the charge current has tapered down to less than 10% of the set maximum current.

Not adjustable with DIP switches.

See ’tubular plate traction battery charge curve’ in VEConfigure.

Storage voltage, Repeated Absorption Time, Absorption Repeat Interval

See Section 2.

Bulk Protection

When this setting is ‘on’, the bulk charging time is limited to 10 hours. A longer charging time could indicate a system error (e.g. a battery cell short-circuit).

AC input current limit

These are the current limit settings for which PowerControl and PowerAssist come into operation:


PowerAssist setting range, grid in-line topology

9.5 A – 50 A

PowerAssist setting range, grid parallel topology with external 100A current transformer

9.5 A – 100 A

Factory setting: maximum grid in-line topology value.

UPS feature

If this setting is ‘on’ and AC on the input fails, the MultiPlus-II switches to inverter operation practically without interruption.

The output voltage of some small generator sets is too unstable and distorted for using this setting – the MultiPlus-II would continually switch to inverter operation. For this reason, the setting can be turned off. The MultiPlus-II will then respond less quickly to AC input voltage deviations. The switchover time to inverter operation is consequently slightly longer, but most equipment (most computers, clocks or household equipment) is not adversely impacted.

Recommendation: Turn the UPS feature off if the MultiPlus-II fails to synchronise, or continually switches back to inverter operation.

Dynamic current limiter

Intended for generators, the AC voltage being generated by means of a static inverter (so-called ‘inverter’ generators). In these generators, engine rpm is reduced in case of low load: this reduces noise, fuel consumption and pollution. A disadvantage is that the output voltage will drop severely or even completely fail in the event of a sudden load increase. More load can only be supplied after the engine is up to speed.

If this setting is ‘on’, the MultiPlus-II will start supplying extra power at a low generator output level and gradually allow the generator to supply more, until the set current limit is reached. This allows the generator engine to get up to speed.

This setting is also often used for ‘classical’ generators that respond slowly to sudden load variation.

Weak AC

Strong distortion of the input voltage can result in the charger hardly operating or not operating at all. If WeakAC is set, the charger will also accept a strongly distorted voltage, at the cost of greater distortion of the input current.

Recommendation: Turn WeakAC on if the charger is hardly charging or not charging at all (which is quite rare!). Also turn on the dynamic current limiter simultaneously, and reduce the maximum charging current to prevent overloading the generator if necessary.


When WeakAC is on, the maximum charge current is reduced by approximately 20%.


Change this setting only after consulting with Victron Energy or with an engineer trained by Victron Energy!

Programmable relay

The relay can be programmed for all kinds of other applications, for example as a starter relay for a generator.

Auxiliary AC output (AC-out-2)

Intended for non-critical loads and directly connected to the AC input. With current measurement circuit to enable PowerAssist.

5.3. Configuring the MultiPlus-II

The following hardware is required:

A MK3-USB (VE.Bus to USB) interface.

Alternatively, the Interface MK2.2b (VE.Bus to RS232) can be used (RJ45 UTP cable needed).

5.3.1. VE.Bus Quick Configure Setup

VE.Bus Quick Configure Setup is a software program with which systems with a maximum of three Multis (parallel or three phase operation) can be configured in a simple manner.

The software can be downloaded free of charge at

5.3.2. VE.Bus System Configurator

For configuring advanced applications and/or systems with four or more Multis, VE.Bus System Configurator software must be used.

The software can be downloaded free of charge at .

5.3.3. VEConfigure

All settings can be changed with a PC and free of charge software VEConfigure, downloadable from our website See this manual for more information -

5.3.4. VictronConnect

The MultiPlus is configured using VictronConnect. More general information about the VictonConnect App - how to install it; how to pair it with your device; and how to update firmware, for example - can be found by referring to the overall VictronConnect manual.