Victron energy MultiPlus-II 12/3000/120 Manuel page 4

2. DESCRIPTION
2.1 Boats, vehicles and other stand-alone applications
The basis of the MultiPlus-II is an extremely powerful sine inverter, battery charger and transfer switch in a compact casing.
Important features:
Automatic and uninterruptible switching
In the event of a supply failure or when the generating set is switched off, the MultiPlus-II 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 highly suitable as an emergency power
system in industrial and telecommunication applications.
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.
Please enter "AC-out-2" in the search box on our website and find the latest information about other applications.
Three phase capability
Three units can be configured for three-phase output. Up to 6 sets of three units can be parallel connected to provide 45 kW / 54 kVA
inverter power and more than 600 A charging capacity.
PowerControl – maximum use of limited AC power
The MultiPlus-II 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 then takes other power users into account, and only uses 'surplus' current for charging purposes.
PowerAssist – Extended use of generator or shore current: the MultiPlus-II "co-supply" feature
This feature takes the principle of PowerControl to a further dimension allowing the MultiPlus-II to supplement the capacity of the
alternative source. Where peak power is often required only for a limited period, the MultiPlus-II 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.
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.
External current transformer (optional)
External current transformer option to implement PowerControl and PowerAssist with external current sensing.
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.
2.2 On-grid and off-grid systems combined with PV
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.
Frequency shift
When solar inverters are connected to the output of a MultiPlus-II, 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 will slightly increase the AC frequency to reduce the output of the solar inverter.
Built-in Battery Monitor
The ideal solution when the MultiPlus-II 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.
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 and batteries, this problem can be solved: the MultiPlus-II can replace the grid
during a power failure. When the sustainable energy sources produce more power than needed, the MultiPlus-II will use the surplus to
charge the batteries; in the event of a shortfall, the MultiPlus-II will supply additional power from the battery.
Programmable
All settings can be changed with a PC and free of charge software, downloadable from our website www.victronenergy.com
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