2. Description
2.1. 120/240V input and output, or 120V input and output (always 120V output when in inverter mode)
The AC input can be supplied from a split-phase 120/240V source or a single-phase 120V source.
When an AC source is available, the inverter/charger will feed through the AC to its output. The output will therefore mirror the AC input.
The inverter/charger connects to the neutral and the preferred input line (L1). The power needed to charge the batteries will therefore be drawn from L1.
The inverter/charger switches to inverter operation when no AC source is available. The inverter output is 120V single phase. In invert mode, the inverter/charger connects both output lines (L1 and L2) together to provide 120VAC to loads on either line.
Any 240V loads will therefore be supplied only when the inverter/charger is supplied by a split-phase AC source. This prevents heavy loads such as water heaters or 240V air conditioners from discharging the battery.
240V loads should be connected between L1 and L2 which could be either AC-out-1 or AC-out-2. There will be 240V between them when the unit is connected to a split-phase input and 0V otherwise (single-phase grid or inverter mode). The voltage L1-N and L2-N will be 120V regardless of single or split-phase input. This can be better understood when looking at the power flow diagrams located in Power flow diagrams.
2.2. Battery charger
2.2.1. 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 (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.
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 4A and has a slightly lower output voltage (12V and 24V models only).
2.2.2. Victron Lithium Battery Smart
If Victron Lithium Smart batteries are used, use the VE.Bus BMS V2 or the Lynx Smart BMS.
2.2.3. Other lithium batteries
If other lithium batteries are used, follow this link for a list of compatible battery types and how to install and configure them: https://www.victronenergy.com/live/battery_compatibility:start.
2.2.4. 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. It can be downloaded from: https://www.victronenergy.com/upload/documents/Book-Energy-Unlimited-EN.pdf, or a hard copy can be ordered from: https://www.victronenergy.com/orderbook
For more information on adaptive charging, please refer to the technical paper: Adaptive charging, how it works.