Battery charger
The batteries can be charged by solar energy using the built-in dual tracker MPPT solar controllers, a compatible AC supply connected to the AC input, or an AC PV grid inverter connected to the AC output. The two built-in MPPT trackers have a power limit of 3000W each for a total power of 6000W. The maximum total battery charging current is 100A.
If an additional PV grid inverter is connected (max. 5000W) the maximum total battery charging current is still limited to 100A. The maximum charging current of 100A is reduced if the battery voltage goes above 60V. A custom maximum charge current value (up to 100A) can also be defined by the installer in VictronConnect. If using a PV grid inverter, it will only charge the battery to ~95%.
The maximum charge current from AC sources depends upon the input voltages, the battery current and ambient temperature. For example, at 230V AC input, 57.6V battery voltage and 25°C the maximum charge current will be 88A. See Limitations section for a more detailed graph.
The charger algorithm is the same as for the BlueSolar and SmartSolar MPPT solar controllers. This provides built-in battery preset parameters, and allows for expert mode to define additional charging parameters.
Warning
Do not recharge non-rechargeable batteries,
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.
Lithium-ion batteries
Victron-NG or LiFePO4 Smart batteries
When using Victron LiFePO4 batteries, the system will need to be wired using a compatible Victron BMS.
Lynx Smart BMS NG
This BMS is recommended when also using a GX device in the system. It is connected via the VE.Can bus interface. Note when using this BMS set the Remote Mode to Remote on/off when commissioning the product in VictronConnect.
Small BMS NG
This BMS is connected to the Multi RS19 Solar using the allow to charge, and allow to discharge contacts from the Victron smallBMS NG to the I/O connection port of the Multi RS19 Solar. Note when using this BMS configure for Remote Mode 2-wire BMS when commissioning the product in VictronConnect.
Compatible BMS-Can lithium batteries
Compatible BMS-Can lithium batteries can be used with the Multi RS19 Solar however it is a requirement that those batteries are connected via the BMS-Can port of the GX device (such as the Cerbo GX), and not to the Multi RS19 Solar communications interface directly. See the Victron Battery Compatibility Guide for more specific information.
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: 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 web portal. Successful completion of this training should be considered essential for system designers and installers, and is recognised with a graduation certificate.