Victron Energie MultiPlus-II GX User manual

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# MultiPlus-II GX - Product Manual
1. # Introduction
The Victron MultiPlus-II GX integrates the following elements:
A powerful MultiPlus-II inverter/charger
A GX card with a 2x16 character display
These elements come prewired, and preconfigured together inside a single unit. This simplifies installation, saving
time and money.
This document explains:
Features
Behaviour
Specifications
Limitations
Installation instructions
Troubleshooting steps
You must read it to understand how to use your product safely and reliably.
This manual applies to:
MultiPlus-II GX 48/3000/35-32
2. # Latest Documentation
You can quickly access the latest version of this manual online by visiting the following link: https://ve3.nl/MultiPlus-
ii-gx
Or scanning this QR code with your phone:

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3. # Safety Instructions
Please read the documentation supplied with this product first, so that you are familiar with the safety signs and
directions before using the product. This product is designed and tested in accordance with international standards.
The product should be used for the designated application only.
WARNING
DANGER OF ELECTRICAL SHOCK
The product is used in combination with a permanent energy source (battery). Even if the product is switched off, a
dangerous electrical voltage can occur at the input and/or output terminals. Always switch the AC power off and
disconnect the battery before performing maintenance.
The product contains no internal user-serviceable parts. Do not remove the front panel and do not put the product
into operation unless all panels are fitted. All maintenance should be performed by qualified personnel.
Never use the product at sites where gas or dust explosions could occur. Refer to the specifications provided by the
manufacturer of the battery to ensure that the battery is suitable for use with this product. The battery
manufacturer's safety instructions should always be observed.
This product is not intended for use by persons (including children) with reduced physical, sensory or mental
capabilities, or lack of experience and knowledge, unless they have been given supervision or instruction concerning
use of the product by a person responsible for their safety. Children should be supervised to ensure that they do not
play with the product.
WARNING
Do not lift heavy objects unassisted
3.1. # Installation
Read the installation instructions before commencing installation activities. For electrical work, follow the local
national wiring standard, regulation and this installation instructions.
This product is a safety class I device (supplied with a ground terminal for safety purposes). Its AC input and/or
output terminals must be provided with uninterruptible grounding for safety purposes. An additional grounding
point bonded to the chassis is located on the inside the terminal cover of the product. See Appendix

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The ground conductor should be at least 4mm². If it can be assumed that the grounding protection is damaged, the
product should be taken out of operation and prevented from accidentally being put into operation again; contact
qualified maintenance personnel.
Ensure that the connection cables are provided with fuses and circuit breakers. Never replace a protective device by
a component of a different type. Refer to the connection of battery cables section of the manual for the correct part.
Do not invert neutral and phase when connecting the AC.
Check before switching the device on whether the available voltage source conforms to the configuration settings of
the product as described in the manual.
Ensure that the equipment is used under the correct operating conditions. Never operate it in a wet or dusty
environment.
Ensure that there is always sufficient free space around the product for ventilation, and that ventilation openings are
not blocked.
Install the product in a heatproof environment. Ensure therefore that there are no chemicals, plastic parts, curtains
or other textiles, etc. in the immediate vicinity of the equipment.
This inverter is provided with an internal isolation transformer providing reinforced insulation.
3.2. # Transport and storage
On storage or transport of the product, ensure that the mains supply and battery leads are disconnected.
No liability can be accepted for damage in transit if the equipment is not transported in its original packaging.
Store the product in a dry environment; the storage temperature should range from –20°C to 60°C.
Refer to the battery manufacturer's manual for information on transport, storage, charging, recharging and disposal
of the battery.
4. # Product Description
The basis of the MultiPlus-II is an extremely powerful sine inverter, battery charger and transfer switch in a compact
casing. It is suited for use in Marine, Automotive, as well as stationary land-based applications.
4.1. # Features applying to all applications
4.1.1. # GX LCD display
A backlit 2 x 16 character display screen shows system parameters.
4.1.2. # CAN-bus Connections
A CAN-bus connection allows connecting of VE.Can products as for example Victron MPPT Solar Chargers, or a
Lynx Shunt VE.Can. Also, it can be configured to connect to CAN-bus BMS batteries.
4.1.3. # Ethernet and Wifi

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Ethernet and Wifi connections allow for local and remote system monitoring, as well as connection to Victron's free
VRM portal for long term system performance information.
4.1.4. # Automatic and uninterruptible switching
In the event of a supply failure or when the generating set is switched off, the MultiPlus-II GX will switch over to
inverter operation and take over the supply of the connected devices. This is done so quickly that operation of
computers and other electronic devices is not disturbed (Uninterruptible Power Supply or UPS functionality). This
makes the MultiPlus-II GX highly suitable as an emergency power system in industrial and telecommunication
applications.
4.1.5. # Two AC outputs
Besides the usual uninterruptable output (AC-out-1), an auxiliary output (AC-out-2) is available that disconnects its
load in the event of battery operation. Example: an electric boiler that is allowed to operate only if the genset is
running or shore power is available. There are several applications for AC-out-2.
4.1.6. # Three phase capability
The unit can be connected with others and configured for three-phase output. Up to 6 sets of three can be parallel
connected to provide 45 kW / 54 kVA inverter power and more than 600A charging capacity.
4.1.7. # PowerControl – maximum use of limited AC power
The MultiPlus-II GX can supply a huge charging current. This implies heavy loading of the AC mains or generator.
Therefore a maximum current can be set. The MultiPlus-II GX then takes other power users into account, and only
uses 'surplus' current for charging purposes.
4.1.8. # PowerAssist – Extended use of generator or shore current: the MultiPlus-II GX
This feature takes the principle of PowerControl to a further dimension allowing the MultiPlus-II GX to supplement
the capacity of the alternative source. Where peak power is often required only for a limited period, the MultiPlus-II
GX will make sure that insufficient AC mains or generator power is immediately compensated for by power from the
battery. When the load reduces, the spare power is used to recharge the battery.
4.1.9. # Programmable
All settings can be changed with a PC and free of charge software, downloadable from our website
www.victronenergy.com. See this manual for more information - https://docs.victronenergy.com/veconfigure.html
4.1.10. # Programmable relay
The MultiPlus is equipped with a programmable relay. The relay can be programmed for different applications, for
example as a starter relay for a generator.
4.1.11. # External current transformer (optional)
External current transformer option to implement PowerControl and PowerAssist with external current sensing.
4.1.12. # Programmable analog/digital input/output ports (Aux in 1 and Aux in 2, see appendix)
The MultiPlus is equipped with 2 analog/digital input/output ports.
These ports can be used for several purposes. One application is communication with the BMS of a lithium-ion
battery.

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4.2. # Features specific On-grid and off-grid systems combined with PV
4.2.1. # External current transformer (optional)
When used in a grid-parallel topology the internal current transformer cannot measure the current to or from the
mains. In this case an external current transformer has to be used. See appendix A.
4.2.2. # Frequency shift
When solar inverters are connected to the output of a MultiPlus-II GX, excess solar energy is used to recharge the
batteries. Once the absorption voltage is reached, charge current will reduce and excess energy will be fed back into
the mains. If the mains is not available, the MultiPlus-II GX will slightly increase the AC frequency to reduce the
output of the solar inverter.
4.2.3. # Built-in Battery Monitor
The ideal solution when the MultiPlus-II GX is part of a hybrid system (diesel generator, inverter/chargers, storage
battery, and alternative energy). The built-in battery monitor can be set to start and stop the generator:
Start at a preset % discharge level, and/or
start (with a preset delay) at a preset battery voltage, and/or
start (with a preset delay) at a preset load level.
Stop at a preset battery voltage, or
stop (with a preset delay) after the bulk charge phase has been completed, and/or
stop (with a preset delay) at a preset load level.
4.2.4. # Autonomous operation when the grid fails
Houses or buildings with solar panels or a combined micro-scale heating and power plant or other sustainable
energy sources have a potential autonomous energy supply which can be used for powering essential equipment
(central heating pumps, refrigerators, deep freeze units, Internet connections, etc.) during a power failure. A problem
is however that grid connected sustainable energy sources drop out as soon as the grid fails. With a MultiPlus-II GX
and batteries, this problem can be solved: the MultiPlus-II GX can replace the grid during a power failure. When the
sustainable energy sources produce more power than needed, the MultiPlus-II GX will use the surplus to charge the
batteries; in the event of a shortfall, the MultiPlus-II GX will supply additional power from the battery.
4.3. # Battery charger
4.3.1. # Lead-acid batteries
Adaptive 4-stage charge algorithm: bulk – absorption – float – storage
The microprocessor-driven adaptive battery management system can be adjusted for various types of batteries. The
adaptive function automatically adapts the charging process to battery use.
The right amount of charge: variable absorption time
In the event of slight battery discharge, absorption is kept short to prevent overcharging and excessive gas
formation. After deep discharging, the absorption time is automatically extended in order to fully charge the battery.
Preventing damage due to excessive gassing: the BatterySafe mode

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If, in order to quickly charge a battery, a high charge current in combination with a high absorption voltage has
been chosen, damage due to excessive gassing will be prevented by automatically limiting the rate of voltage
increase once the gassing voltage has been reached.
Less maintenance and aging when the battery is not in use: the Storage mode
The Storage mode kicks in whenever the battery has not been subjected to discharge during 24 hours. In the
Storage mode float voltage is reduced to 2,2V/cell (13,2V for 12V battery) to minimise gassing and corrosion of the
positive plates. Once a week the voltage is raised back to the absorption level to 'equalize' the battery. This feature
prevents stratification of the electrolyte and sulphation, a major cause of early battery failure.
Battery voltage sense: the correct charge voltage
Voltage loss due to cable resistance can be compensated by using the voltage sense facility to measure voltage
directly on the DC bus or on the battery terminals.
Battery voltage and temperature compensation
The temperature sensor (supplied with the product) serves to reduce charging voltage when battery temperature
rises. This is particularly important for maintenance-free batteries, which could otherwise dry out by overcharging.
4.3.2. # Li-ion batteries
Victron LiFePO4 Smart batteries
Use the VE.Bus BMS
4.3.3. # Other Li-ion batteries
Please see https://www.victronenergy.com/live/battery_compatibility:start
4.3.4. # More on batteries and battery charging
Our book 'Energy Unlimited' offers further information on batteries and battery charging, and is available free of
charge on our website: www.victronenergy.com/support-and-downloads/whitepapers
For more information on adaptive charging, please also refer to the General Technical Information on our website.
4.4. # ESS – Energy Storage Systems: feeding energy back into the grid
When the MultiPlus-II GX is used in a configuration in which it will feed back energy into the grid it is required to
enable grid code compliance by selecting the appropriate grid code country setting with the VEConfigure tool.
Once set, a password will be required to disable grid code compliance or change grid code related parameters.
If the local grid code is not supported by the MultiPlus-II GX an external certified interface device should be used to
connect the MultiPlus-II GX to the grid.
The MultiPlus-II GX can also be used as a bidirectional inverter operating parallel to the grid, integrated into a
customer designed system (PLC or other) that takes care of the control-loop and grid measurement,
Special note regarding NRS-097 (South Africa)
1. The maximum allowed impedance of the network is 0.28Ω + j0.18Ω

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2. The inverter is fulfilling the unbalance requirement in case of multiple single phase units only when the Color
Control GX is part of the installation.
Special notes regarding AS 4777.2 (Australia/New Zealand)
1. Certification and CEC approval for off-grid use does NOT imply approval for grid-interactive installations.
Additional certification to IEC 62109.2 and AS 4777.2.2015 are required before grid-interactive systems can be
implemented. Please check the Clean Energy Council website for current approvals.
2. DRM – Demand Response Mode When the AS4777.2 grid code has been selected in VEconfigure, DRM 0
functionality is available on port AUX1 (see appendix A. To enable grid connection, a resistance of between
5kOhm and 16kOhm must be present between the terminals of port AUX1 (marked + and - ). The MultiPlus-II
GX will disconnect from the grid in case of an open circuit or a short circuit between the terminals of port
AUX1. The maximum voltage that may be present between the terminals of port AUX1 is 5V. Alternatively, if DRM
0 is not required, this functionality can be disabled with VEConfigure.
5. # Operation
5.1. # On/Off/Charger Only Switch
The switch is located on the underside to the bottom right of the MultiPlus-II GX.
The swich has three positions. The centre position 0 is Off. The I position is On, and the II position is Charger Only.
When switched to 'I / On' (rocked towards the back of the unit), the product will come into operation and the
inverter is fully functional.
If an AC voltage is connected to the 'AC in' terminal, it will be switched through to the 'AC out' terminal, if within
specifications. The inverter will switch off, and the charger commences charging. 'Bulk', 'absorption' or 'float' will
display, depending on the charger mode.
If the voltage at the 'AC-in' terminal is rejected, the inverter will switch on.
When the switch is switched to 'II / charger only', only the battery charger of the Multi will operate (if mains voltage is
present). In this mode input voltage also is switched through to the 'AC out' terminal.
NOTE: When only the charger function is required, ensure that the switch is switched to 'II / charger only'. This
prevents the inverter from being switched on if the mains voltage is lost, thus preventing your batteries from running
flat.
6. # GX LCD Interface
The display screen will present useful information about your system.
6.1. # On/off behaviour
When the MultiPlus-II GX is switched off with the physical switch on the device or with the Remote on/off terminals,
then the GX card is off as well. If you switch the MultiPlus-II GX remotely, using a Digital Multi Control, then the GX
card will be remain powered. Also when switching the inverter/charger off from within the GX menus, the GX card
will remain powered.

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Lastly, when the inverter/charger switches itself off due to an alarm, such as low battery or overtemperature, then the
GX Card will remained powered and functional as well.
6.2. # Push button behaviour
When the GX Card is on, pushing the button beside the screen will activate the backlight. The backlight will turn
itself off after 5 minutes.
Once the backlight has been activated, pushing the button again will cycle through the available display options.
Some options will be displayed automatically, and other require a button push to display.
6.3. # Information displayed
Solar Power, Voltage and Charge state (if connected)
ESS/DVCC reason codes (if active)
Solar Daily Yield
Inverter/charger charge state (eg Bulk, ESS)
Battery State of Charge, Power and Voltage
Network IP Address and Connection Type (if connected).
AC input and output Power
In a system with more than one phase, there will be additional AC input and output information available, eg
Phase 1 AC input Voltage and Power.
Phase 1 AC output Voltage and Power.
Phase 2 AC input Voltage and Power.
Phase 2 AC output Voltage and Power.
Phase 3 AC input Voltage and Power.
Phase 3 AC output Voltage and Power.
6.4. # Error Code Display
If there is an error with the system, the error code will be displayed on the screen. The screen will display VE.Bus
error code numbers, and MPPT error codes (if connected).
Basic information about the VE.Bus Error codes are in the Error Indications section.
For further details about the error codes please see:
VE.Bus Error Codes
MPPT Error Codes
The error will display until it is cleared.
7. # Installation

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This product contains potentially dangerous voltages. It should only be installed under the supervision of a suitable
qualified installer with the appropriate training, and subject to local requirements. Please contact Victron for further
information or necessary training.
7.1. # Location
The product must be installed in a dry and well-ventilated area, as close as possible to the batteries. There should be
a clear space of at least 10 cm around the product for cooling.
WARNING
Excessively high ambient temperature will result in the following:
Reduced service life.
Reduced charging current.
Reduced peak capacity, or shutdown of the inverter. Never position the appliance directly above the
batteries.
The MultiPlus-II GX is suitable for wall mounting. For mounting purposes, a hook and two holes are provided at the
back of the casing (see appendix G). The device can be fitted either horizontally or vertically. For optimal cooling,
vertical fitting is preferred.
WARNING
The interior of the product must remain accessible after installation.
Try and keep the distance between the product and the battery to a minimum in order to minimize cable voltage
losses.
For safety purposes, this product should be installed in a heat-resistant environment. You should prevent the
presence of e.g. chemicals, synthetic components, curtains or other textiles, etc., in the immediate vicinity.
7.2. # Connection of battery cables
In order to utilize the full capacity of the product, batteries with sufficient capacity and battery cables with sufficient
cross section should be used. See table.
48/3000/35

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Recommended battery capacity (Ah) 100–400
Recommended DC fuse 125 A
Recommended cross section (mm²) per + and - connection terminal
0 – 5 m 35 mm²
5 – 10 m 70 mm²
Remark: Internal resistance is the important factor when working with low capacity batteries. Please consult your
supplier or the relevant sections of our book 'Energy Unlimited', downloadable from our website.
7.3. # Battery Connection Procedure
Proceed as follows to connect the battery cables:
WARNING
Use a torque wrench with insulated box spanner in order to avoid shorting the battery. Maximum torque: 14 Nm
Avoid shorting the battery cables.
WARNING
Specific care and attention must be taken when making the battery connections. Correct polarity must be
confirmed with a multimeter before connection. Connecting a battery with incorrect polarity will destroy the
device and is not covered by warranty.
Undo the two screws at the bottom of the enclosure and remove the service panel.
Connect the battery cables. First the - cable then the +. Be aware that there may be a spark when making the
battery connections.
Tighten the nuts to the prescribed torques for minimal contact resistance.
7.4. # Connection of the AC cabling

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WARNING
The MultiPlus-II GX is a safety class I product (supplied with a ground terminal for safety purposes). Its AC input
and/or output terminals and/or grounding point on the inside of the product must be provided with an
uninterruptible grounding point for safety purposes. see Appendix.
In a fixed installation, an uninterruptable grounding can be secured by means of the grounding wire of the AC
input. Otherwise the casing must be grounded.
The MultiPlus-II GX is provided with a ground relay (relay H, see appendix B) that automatically connects the
Neutral output to the chassis if no external AC supply is available. If an external AC supply is provided, the
ground relay H will open before the input safety relay closes. This ensures the correct operation of an earth
leakage circuit breaker that is connected to the output.
In a mobile installation (for example, with a shore current plug), interrupting the shore connection will
simultaneously disconnect the grounding connection. In that case, the casing must be connected to the chassis
(of the vehicle) or to the hull or grounding plate (of the boat). In case of a boat, direct connection to the shore
ground is not recommended because of potential galvanic corrosion. The solution to this is using an isolation
transformer. Torque: 2 Nm
The terminal blocks can be found on the printed circuit board, see Appendix A.
Do not invert neutral and phase when connecting the AC.
AC-in The AC input cable can be connected to the terminal block 'AC–in'. From left to right: "N" (neutral), "PE"
(earth) and "L" (phase) The AC input must be protected by a fuse or magnetic circuit breaker rated at 32A or
less, and cable cross-section must be sized accordingly. If the input AC supply is rated at a lower value, the
fuse or magnetic circuit breaker should be down sized accordingly.
AC-out-1 The AC output cable can be connected directly to the terminal block 'AC-out'. From left to right: "N"
(neutral), "PE" (earth) and "L" (phase) With its PowerAssist feature the Multi can add up to 3kVA (that is 3000 /
230 = 13A) to the output during periods of peak power requirement. Together with a maximum input current
of 32A this means that the output can supply up to 32 + 13 = 45 A. An earth leakage circuit breaker and a fuse
or circuit breaker rated to support the expected load must be included in series with the output, and cable
cross-section must be sized accordingly.
AC-out-2 A second output is available that disconnects its load in the event of battery operation. On these
terminals, equipment is connected that may only operate if AC voltage is available on AC-in-1, e.g. an electric

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boiler or an air conditioner. The load on AC-out-2 is disconnected immediately when the inverter/charger
switches to battery operation. After AC power becomes available on AC-in-1, the load on AC-out-2 will be
reconnected with a delay of approximately 2 minutes. This to allow a genset to stabilise.
7.5. # Optional Connections
A number of optional connections are possible:
7.5.1. # Remote Control
The product can be remotely controlled in two ways.
With an external switch (connection terminal M, see appendix A). Operates only if the switch on the MultiPlus-II
GX is set to "on".
With a Digital Multi Control panel (connected to one of the two RJ45 sockets L, see appendix A). Operates only
if the switch on the MultiPlus-II GX is set to "on"
The Digital Multi Control panel has a rotary knob with which the maximum current of the AC input can be set: see
PowerControl and PowerAssist.
7.5.2. # Programmable relay
The product is equipped with a programmable relay.
The relay can be programmed for all kinds of other applications, for example as a starter relay for a generator.
7.5.3. # Programmable analog/digital input/output ports
The product is equipped with 2 analog/digital input/output ports.
These ports can be used for several purposes. One application is communication with the BMS of a lithium-ion
battery.
7.5.4. # Voltage sense (connection terminal J, see appendix A)
For compensating possible cable losses during charging, two sense wires can be connected with which the voltage
directly on the battery or on the positive and negative distribution points can be measured. Use wire with a cross-
section of 0,75mm².
During battery charging, the inverter/charger will compensate the voltage drop over the DC cables up to a
maximum of 1 Volt (i.e. 1V over the positive connection and 1V over the negative connection). If the voltage drop
threatens to become larger than 1V, the charging current is limited in such a way that the voltage drop remains
limited to 1V.
7.5.5. # Temperature sensor (connection terminal J, see appendix A)
For temperature-compensated charging, the temperature sensor (supplied with the inverter/charger) can be
connected. The sensor is isolated and must be fitted to the negative terminal of the battery.
7.5.6. # Parallel Connection
It is required to use identical units for three phase and parallel systems. In this case, as only one GX device is allowed
per system, if you wish to parallel and/or three phase with a MultiPlus-II GX, you must find the same model
MultiPlus-II to pair.

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To assist with finding identical units, consider instead using MultiPlus-II for parallel and three phase systems, and an
external GX device.
Up to six units can be connected in parallel. When connecting a MultiPlus-II GX with MultiPlus-II in a parallel system,
the following requirements must be met:
WARNING
It is essential the negative battery terminal between the units is always connected. A fuse or circuit breaker
is not allowed on the negative.
All units must be connected to the same battery
A maximum of six units connected in parallel.
The devices must be identical (aside from GX part) and have the same firmware.
The DC connection cables to the devices must be of equal length and cross-section.
If a positive and a negative DC distribution point is used, the cross-section of the connection between the
batteries and the DC distribution point must at least equal the sum of the required cross-sections of the
connections between the distribution point and the units.
Always interconnect the negative battery cables before placing the UTP cables.
Place the MultiPlus-II and MultiPlus-II GX units close to each other, but allow at least 10cm for ventilation
purposes under, above and beside the units.
UTP cables must be connected directly from one unit to the other (and to the remote panel). Connection or
splitter boxes are not permitted.
Only one remote control means (panel or switch) can be connected to the system. That means only one GX.
7.5.7. # Three-phase operation
The MultiPlus-II GX can also be used in 3-phase wye (Y) configuration. To this end, a connection between the
devices is made by means of standard RJ45 UTP cables (the same as for parallel operation). The system (MultiPlus-II
GX plus an optional control panel) will require subsequent configuration.
Pre-requisites: see Section Voltage Sense
1. Note: the MultiPlus-II GX is not suitable for 3-phase delta (Δ) configuration.
2. When the AS4777.2 grid code has been selected in VEConfigure, only 2 units in parallel per phase are allowed
in a three phase system.
For full details on parallel and three-phase configuration always discuss with your Victron distributor first and please
see this specific manual: https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems
7.5.8. # Connection to the VRM Portal
Connection of the MultiPlus-II GX to VRM requires an internet connection. This can be made via wifi, or preferably a
hardwired ethernet cable to an internet connected router.
The VRM site id is located on a sticker inside the cable connections area of the device.
For more information to set up VRM, refer to the VRM Getting Started Manual.
8. # Configuration
This section is intended mainly for stand-alone applications

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For grid connected Energy Storage Systems (ESS) please see https://www.victronenergy.com/live/ess:start
Settings may only be changed by a suitable qualified installer with the appropriate training, and subject to local
requirements. Please contact Victron for further information or necessary training.
Read the instructions thoroughly before implementing changes.
During setting of the charger, the AC input must be removed.
8.1. # Standard settings: ready for use
On delivery, the MultiPlus-II GX is set to standard factory values. In general, these settings are suitable for single-unit
operation.
WARNING
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 GX factory settings
Setting Value
Inverter frequency 50 Hz
Input frequency range 45 – 65 Hz
Input voltage range 180 – 265 VAC
Inverter voltage 230 VAC
Stand-alone / parallel / 3-phase stand-alone
AES (Automatic Economy Switch) off
Ground relay on
Charger on/ off on
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 off
Absorption voltage 57.6V
Absorption time up to 8 hours (depending on bulk time)
Float voltage 55.2V
Storage voltage 52.8V (not adjustable)
Repeated absorption time 1 hour
Absorption repeat interval 7 days
Bulk protection on
AC input current limit 32A (= adjustable current limit for PowerControl and PowerAssist functions)
UPS feature on

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Dynamic current limiter off
WeakAC off
BoostFactor 2
Programmable relay alarm function
PowerAssist on
8.2. # 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.
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 GX. The MultiPlus-II GX 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 GX. The MultiPlus-II GX synchronises within this range with the AC input.
The output voltage is then equal to the input voltage.
Adjustability:
Lower limit: 180 – 230V
Upper limit: 230 – 270V
Note : the standard lower limit setting of 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 230V.
The solution is to increase the lower limit setting to 210VAC (the output of AVR generators is generally very stable), or
to disconnect the MultiPlus-II GX 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 GX in battery operation.
Adjustability: 210 – 245V

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Stand-alone / parallel operation / 2-3 phase setting
Using multiple 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 a single device in standalone operation.
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 GX, 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 default settings are:
Action Threshold
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'.
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.

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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.
8.2.1. # Equalisation
Traction batteries require regular additional charging. In the equalisation mode, the MultiPlus-II GX will charge with
increased voltage for one hour (4V for a 48V battery). The charging current is then limited to 1/4 of the set value.
Equalisation mode supplies a higher charging voltage than most DC consuming devices can cope with. These
devices must be disconnected before additional charging takes place.
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 (68V for a 48V battery) once the charge current has tapered down to less than 10% of the set
maximum current.
See 'tubular plate traction battery charge curve' in VEConfigure.
Storage voltage, Repeated Absorption Time, Absorption Repeat Interval
See Appendix E.
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: from 5,3 A to 32 A.
Factory setting: the maximum value (32 A).
UPS feature
If this setting is 'on' and AC on the input fails, the MultiPlus-II GX 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
GX would continually switch to inverter operation. For this reason, the setting can be turned off. The MultiPlus-II GX
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.

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Recommendation : Turn the UPS feature off if the MultiPlus-II GX 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 GX 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.
Note: when WeakAC is on, the maximum charge current is reduced by approximately 20%.
BoostFactor This value adjusts the PowerAssist behaviour. If you are experiencing issues with PowerAssist (eg
overload), please consult with a specialist trained by Victron Energy before attempting to modify.
Programmable relay
The MultiPlus-II GX is equipped with multiple programmable relays. These relays 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.
9. # Configuring the MultiPlus-II GX
The following hardware is required:
A MK3-USB (VE.Bus to USB) interface.
RJ45 UTP cable.
9.1. # VEConfigure PC software
Configuration of the MultiPlus-II GX is performed with a tool called VEConfigure. Additionally please read the
seperate VEConfigure manual and undertake Victron training for safe use of this tool.

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9.2. # 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 www.victronenergy.com.
9.3. # 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 www.victronenergy.com .
10. # Maintenance
The MultiPlus-II GX does not require specific maintenance. It will suffice to check all connections once a year. Avoid
moisture and oil/soot/vapours, and keep the device clean.
11. # Error Indications
With the procedures below, most errors can be quickly identified. If an error cannot be resolved, please refer to your
Victron Energy supplier.
11.1. # General error indications
Problem Cause Solution
No output
voltage on
AC-out-2.
MultiPlus-II GX in inverter mode
Multi will not
switch over to
generator or
mains
operation.
Circuit breaker or fuse in the AC-in
input is open as a result of overload.
Remove overload or short circuit on AC-out-1 or AC-out-
2, and reset fuse/breaker.
Inverter
operation not
initiated when
switched on.
The battery voltage is excessively high
or too low. No voltage on DC
connection.
Ensure that the battery voltage is within the correct
range.
'Low battery' The battery voltage is low. Charge the battery or check the battery connections.
'Low battery'
(Shutdown)
The converter switches off because the
battery voltage is too low.
Charge the battery or check the battery connections.
'Overload' The converter load is higher than the
nominal load.
Reduce the load.
'Overload'
(Shutdown)
The converter is switched off due to
excessively high load.
Reduce the load.
'Over
Temperature'
The environmental temperature is high,
or the load is too high.
Install the converter in cool and well-ventilated
environment, or reduce the load.
'Low Bat V Low battery voltage and excessively Charge the batteries, disconnect or reduce the load, or

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Overload'
(Shutdown)
high load. install higher capacity batteries. Fit shorter and/or thicker
battery cables.
'High DC
Ripple'
Ripple voltage on the DC connection
exceeds 1,5Vrms.
Check the battery cables and battery connections. Check
whether battery capacity is sufficiently high, and increase
this if necessary.
'DC Ripple
Shutdown'
The inverter is switched off due to an
excessively high ripple voltage on the
input.
Install batteries with a larger capacity. Fit shorter and/or
thicker battery cables, and reset the inverter (switch off,
and then on again).
The charger
does not
operate.
The AC input voltage or frequency is
not within the range set.
Ensure that the AC input is between 185VAC and
265VAC, and that the frequency is within the range set
(default setting 45-65 Hz).
Circuit breaker or fuse in the AC-in
input is open as a result of overload.
Remove overload or short circuit on AC-out-1 or AC-out-
2, and reset fuse/breaker.
The battery fuse has blown. Replace the battery fuse.
The distortion or the AC input voltage is
too large (generally generator supply).
Turn the settings WeakAC and dynamic current limiter
on.
The charger
does not
operate. 'Bulk
Protection'
shown.
MultiPlus-II GX is in 'Bulk protection'
mode thus, the maximum bulk
charging time of 10 hours is exceeded.
Such a long charging time could
indicate a system error (e.g. a battery
cell short-circuit).
Check your batteries. NOTE: You can reset the error
mode by switching off and back on the MultiPlus-II GX.
The standard MultiPlus-II GX factory setting of the 'Bulk
protection' mode is switched on. The 'Bulk protection'
mode can be switched off with help of VEConfigure only.
The battery is
not
completely
charged.
Charging current excessively high,
causing premature absorption phase.
Set the charging current to a level between 0.1 and 0.2
times the battery capacity.
Poor battery connection. Check the battery connections.
The absorption voltage has been set to
an incorrect level (too low).
Set the absorption voltage to the correct level.
The float voltage has been set to an
incorrect level (too low).
Set the float voltage to the correct level.
The available charging time is too short
to fully charge the battery.
Select a longer charging time or higher charging
current.
The absorption time is too short. For
adaptive charging this can be caused
by an extremely high charging current
with respect to battery capacity, so that
bulk time is insufficient.
Reduce the charging current or select the 'fixed'
charging characteristics.
The battery is
overcharged.
The absorption voltage is set to an
incorrect level (too high).
Set the absorption voltage to the correct level.
The float voltage is set to an incorrect
level (too high).
Set the float voltage to the correct level.
Poor battery condition. Replace the battery.