Standby Mode; Battery Charging; Figure 3-2, Power Flow - Standby Mode - Magnum Energy MagnaSine MS-PE Series Owner's Manual

3.2

Standby Mode

The MS-PE Series features an automatic transfer relay and an internal battery charger when
operating in Standby mode. Standby mode begins whenever AC power (utility grid or generator)
is connected to the inverter's AC input. Once the AC voltage and frequency of the incoming AC
power is within the AC input limits, an automatic AC transfer relay is activated. This transfer
relay passes the incoming AC power through the inverter to power the AC loads on the inverter's
output. This incoming power is also used to activate a powerful internal battery charger to keep
the battery bank charged in case of a power failure. Refer to Figure 3-2 to see the fl ow of power
from the AC input to the DC and AC output while in Standby mode.
AC
IN
AC HOT IN
CB1 (30A)
230
AC NEUT IN
VAC
AC GROUND
DC
DC NEGATIVE
OUT
DC POSITIVE
3.3

Battery Charging

Magnum Energy's MS-PE Series is equipped with an active PFC (Power Factor Corrected) and PI
(Proportional-Integral) multi-stage battery charger. The PFC feature controls the amount of power
used to charge the batteries in order to obtain a power factor as close as possible to 1 (or unity).
This causes the battery charger to look like a resistor to the line (forces the charge current wave
shape to mirror the voltage wave shape). The PI feature allows the charger voltage and current
to change independently. These two features maximize the real power available from either the
utility or generator AC power sources, which translates into less power wasted and greater charging
capabilities than most chargers available today.
When an AC source is connected to the AC input, the inverter begins monitoring for acceptable AC
voltage. Once the inverter has accepted this AC voltage, the AC transfer relay closes and Charge
mode begins. After Charge mode begins, the DC voltage is monitored to determine the charging
stage. If the DC voltage is low (≤12.8 VDC/12-volt models or ≤25.6 VDC/24-volt models), the charger
begins Bulk Charging. If the DC voltage is high (>12.8 VDC/12-volt models or >25.6 VDC/24-volt
models), the charger will skip the Bulk and Absorb Charging stages and go directly to Float Charging.
The multi-stage charger can use up to fi ve different charging stages to help monitor and keep the
batteries healthy. The fi ve stages include an automatic 4-stage charging process: Bulk, Absorb,
Float and Full Charge; and a manual Equalization (EQ) charge stage. The automatic 4-stage charge
process provides complete recharging and monitoring of the batteries without damage due to
overcharging. The EQ stage (requires a remote control display to enable) can be used to stir up
stratifi ed electrolyte and to reverse battery plate sulfation that may have occurred.
While charging, the unit may go into charger back-off protection, which automatically reduces the
charge current to the batteries. This is caused by: 1) The internal temperature is too hot – the
charger automatically reduces the charge rate to maintain temperature; or 2) The AC input voltage
falls below 170 VAC – the charger stops charging to help stabilize the incoming AC voltage.
© 2013 Magnum Energy, Inc.
AC Hot
Transfer Relay
AC
DC
FET Bridge

Figure 3-2, Power Flow - Standby Mode

Power Transformer
Operation
AC
OUT
AC HOT OUT
230
AC NEUT OUT
VAC
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