charging current for a 50V battery will be 80A. If an additional PV grid inverter is connected (max 5000W) the maximum total
charging current is limited to 100A. The maximum charging current of 100A is reduced if battery voltage goes above 60V. A
custom maximum charge current value can also be defined by the installer in VictronConnect. If using a PV grid inverter, it will
only charge the battery to ~95%.
The charger algorithm is the same as for the BlueSolar MPPT solar controllers. This provides built-in battery preset parameters,
and allows for expert mode to define additional charging parameters.
3.12.1. 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
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 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.
3.12.2. Li-ion batteries
Victron LiFePO4 Smart batteries
When using Victron lithium batteries, the system will need to be wired using the allow to charge, and allow to discharge contacts
from the Victron smallBMS to the I/O connection port. This will also need to be configured to BMS mode when commissioning the
product in VictronConnect.
Compatible BMS-Can Lithium Batteries
Compatible BMS-Can lithium batteries can be used with Multi RS Solar however it is a requirement that those batteries to be
connected via the BMS-Can port of the GX device (such as the Cerbo GX), and not to the Multi RS Solar communications
interface directly. See the
Victron Battery Compatibility Guide for more specific information.
3.12.3. 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:
https://www.victronenergy.com/support-and-downloads/technical-information.
For more information on adaptive charging, please also refer to the General Technical Information on our website.
Victron provides a comprehensive Online Training program via the
https://www.victronenergy.com.au/information/training
portal. Successful completion of this training should be considered essential for system designers and installers, and is
recognised with a graduation certificate.
3.13. Setup options
Adaptive three step charging
The Charge Controller is configured for a three step charging process: Bulk – Absorption – Float.
A regular equalization charge can also be programmed.
Bulk- During this stage the controller delivers as much charge current as possible to rapidly recharge the batteries.
Multi RS Solar
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General Description
