2. Description
2.1. General
Multifunctional
The MultiPlus gets its name from the multiple functions it can perform. It is a powerful true sine wave inverter, a sophisticated battery charger that features adaptive charge technology and a high-speed AC transfer switch in a single enclosure. Beside these primary functions, however, the MultiPlus has several advanced features that provide a range of new applications as outlined below.
Uninterrupted AC power
In the event of a grid failure, or shore or generator power being disconnected, the inverter within the MultiPlus is automatically activated and takes over supply to the connected loads. This happens so fast (less than 20 milliseconds) that computers and other electronic equipment will continue to operate without disruption.
Parallel and 3-phase operation capability
Up to 6 inverters can operate in parallel to achieve higher power output.
Operation in 3-phase configuration is also possible.
PowerControl – Dealing with limited generator or shore side power
With a Multi Control Panel a maximum generator or shore current can be set. The MultiPlus will then take account of other AC loads and use whatever is extra for charging, thus preventing the generator or shore supply from being overloaded.
PowerAssist – Boosting the capacity of shore or generator power
This feature takes the principle of PowerControl to a further dimension allowing the MultiPlus Compact to supplement the capacity of the alternative source. Where peak power is so often required only for a limited period, it is possible to reduce the size of generator needed or conversely enable more to be achieved from the typically limited shore connection. When the load reduces, the spare power is used to recharge the battery.
Programmable relay
The MultiPlus is equipped with a programmable relay that by default is set as an alarm relay. The relay can be programmed for all kinds of other applications however, for example as a starter relay for a generator.
2.2. Battery charger
Adaptive 4-stage charging characteristics: 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 Battery Safe mode
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.
Two DC outputs for charging two batteries
The main DC terminal can supply the full output current. The second output, intended for charging a starter battery, is limited to 1A and has a slightly lower output voltage.
Increasing service life of the battery: 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.
More on batteries and charging
Our book ‘Energy Unlimited’ offers further information on batteries and battery charging, and is available free of charge on our website (see www.victronenergy.com → Support & Downloads’ → General Technical Information). For more information on adaptive charging, please also refer to the General Technical Information on our website.
2.3. Self consumption – solar energy storage systems
When the MultiPlus is used in a configuration in which it will feed back energy to the grid it is required to enable grid code compliance by selecting the 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 an external certified interface device should be used to connect the MultiPlus to the grid.
Special note for Australian customers: IEC62109.1 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 Clean Energy Council website for current approvals.