Battery Charging; Figure 3-6, Power Flow - Standby Mode (Ms2000-15B/-20B Models) - Sensata Magnum Energy MS Series Owner's Manual

AC
IN
AC HOT 1 IN
120 VAC
AC NEU IN
AC GROUND
DC
DC NEG
IN
DC POS
Figure 3-6, Power Flow – Standby Mode (MS2000-15B/-20B models)
3.3

Battery Charging

The MS Series is equipped with a 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 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 the AC power source (i.e., utility or generator),
which translates into less power wasted and increased charging capabilities.
When an AC source is connected to the AC input, the inverter begins monitoring for acceptable AC
voltage. Once the AC voltage is accepted, the AC transfer relay closes the charge mode begins.
After the charge mode begins, the inverter's battery voltage is monitored to determine the charging
stage. If the battery voltage is low (≤12.8 VDC/12-volt models, ≤25.6 VDC/24-volt models, or
≤51.2 VDC/48-volt models), the charger begins Bulk charging. If the DC voltage is high (>12.8
VDC/12-volt models, >25.6 VDC/ 24-volt models, or >51.2 VDC/48-volt models), the charger will
skip the Bulk and Absorb charge stages and go directly to Float charging. However, if the incoming
AC power is lost and returns within 2 minutes the charge mode returns to the charge stage it was
in prior to losing AC input—regardless of the battery voltage.
The multi-stage charger in the MS Series can use up to fi ve diff erent charging stages to help
monitor and keep the batteries healthy. The fi ve stages include an automatic 4-stage charging
process (Figure 3-7)—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 any battery plate sulfation
that may have occurred—if recommended by your battery's manufacturer.
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 90 VAC – the charger will stop charging to help stabilize the incoming AC voltage.
© 2016 Sensata Technologies
AC Hot
Transfer Contact
INPUT
(30A)
Neutral-Ground
Transfer Contact
AC
DC
FET Bridge
Power Transformer
Operation
AC HOT 1 OUT
CB1
AC HOT 2 OUT
CB2
AC NEU OUT
AC
OUT
120 VAC
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