Mass Combi Pro 12/3000-150, 24/3500-100
– User and Installation Manual
7
3 HOW IT WORKS
The Mass Combi Pro is a multifunctional charger inverter. It
combines an inverter, a battery charger and an AC transfer
switch.
3.1
Principle
Figure 3-1: Working principle of the Mass Combi Pro
3.1.1
User interface (1)
The Mass Combi Pro user interface consists of a front
switch with status LEDS and MasterBus communication.
3.1.2
AC transfer switch (2)
This part of the Mass Combi Pro regulates the AC energy
flow through the device. The generator
(“GEN”) and mains
(“MAINS”) input are switched, as is AC output 2 (“OUT-2”).
All AC is connected to the inverter (3). If the MAINS plug is
disconnected and the Generator is not running, the inverter
takes over using battery power to provide AC power.
3.1.3
Inverter/ Main charger (3)
This part converts the AC power to DC for charging of the
main battery and it inverts the DC power from the battery to
supply AC to Output 1 and 2.
(“OUT-1” and “OUT-2”).
3.2
Battery charger
The built-in battery charger is electronically controlled. It is
designed for optimal recharging of lead acid (flooded, gel,
AGM) and Li-ion batteries. Battery charging via AC or Solar
input is accomplished with Mastervolt’s 3-Step+ charging
algorithm. With an external AC source connected, the
Mass Combi Pro charger also serves the functions of an
AC to DC converter to supply DC loads which are
connected to the batteries. Simple, automatic operation is
enabled by the microprocessor that is the brain of the
inverter/charger combination.
Figure 3-2:
3-Step+
charge system
3.2.1
3-Step+ charge system
See figure 3-2. The first step of the 3-Step+ charge system
is the BULK phase, in which the output current of the
charger is 100%, and the greater part of the battery
capacity is charged rapidly. The current charges the
batteries and gradually the voltage rises to the absorption
voltage, refer to the specifications. The duration of this
phase depends on the ratio of battery capacity to charger
current, the loads connected and the degree to which the
batteries were discharged to begin with.
The bulk phase is followed by the absorption phase.
Absorption charging ends when the battery is completely
full. Battery voltage remains constant throughout this stage
and the charge current decreases during charging of the
battery. With flooded batteries this stage lasts some four
hours, with gel and AGM around three. Once the battery is
100% full or when the maximum absorption timer has
passed, the charger automatically switches over to the float
phase.
During the float phase the Mass Combi Pro switches to
Float voltage, refer to the specifications, and stabilises this
voltage to maintain the batteries in an optimum condition.
Connected DC-loads are powered directly by the charger.
If the load is higher than charger capacity, the required
additional power comes from the battery, which will be
progressively discharged until the charger automatically
switches back to the bulk phase. Once consumption
decreases, the charger goes back to normal operation of
the 3-Step+ charge system.
As the Mass Combi Pro is equipped with a 3-Step+ charge
system, the batteries can also remain connected to the
Mass Combi Pro in winter. One hour every 12 days the
charger automatically switches to the Bulk phase to keep
the battery working properly and prolong its life span. The
3
2
1
