© 2015 Sensata Technologies
Operation
36
The automatic 4-stage charging process includes:
Bulk Charging:
This is the initial stage of charging. While bulk
charging, the charger supplies the battery with constant current.
The charger remains in bulk charge until the absorption charge
voltage is achieved (14.6 VDC)
*
(per
Battery Type
selection
**
).
Absorb Charging:
This is the second charging stage and begins
after the bulk voltage has been reached. Absorb charging provides
the batteries with a constant voltage and reduces the DC charging
current in order to maintain the absorb voltage setting. The absorb
charging time is 60 minutes (per
Battery AmpHrs
selection
**
).
Float Charging:
The third charging stage occurs at the end of
the absorb charging time. While
fl
oat charging (also known as a
maintenance charge), the batteries are kept fully charged and
ready if needed by the inverter. This stage reduces battery gassing,
minimizes watering requirements (
fl
ooded battery), and ensures
the batteries are maintained at optimum capacity. In this stage, the
charge voltage is reduced to the
fl
oat charge voltage (13.4 VDC)
*
(per
Battery Type
selection
**
)—maintain batteries inde
fi
nitely.
Full Charge (Battery Saver™ mode):
The fourth stage occurs after
four hours in the
fl
oat charging. The Full charge stage maintains the
batteries without overcharging, preventing excessive loss of water
in
fl
ooded batteries or drying out of GEL/AGM batteries. In this
stage, the charger is turned off and begins monitoring the battery
voltage. If the battery voltage drops low (
≤
12.7 VDC), the charger
will automatically initiate another four hours in
fl
oat charge.
DC
Voltage
DC
Current
Bulk Charging
Absorb Charging
Float Charging
Full Charge
Reduced Voltage
Increased Voltage
Constant Voltage
Monitored Voltage
Bulk volts
Float volts
Time
Bulk and Float voltage settings are determined by
the ‘Battery Type’ selection
Constant Current
Reduced Current
No Current
Monitored Current
‘Adj
Charge Rate’
Setting
Goes to Full
Charge after
4 hours in
Float Charge
Absorb Time
(determined by the
‘Adj Batt AmpHrs’
setting)
Figure 4-3, Automatic 4-Stage Charging Graph
* Voltage settings based on the Battery Temperature Sensor (BTS) being
disconnected, or at a temperature of 77°F (25°C). If BTS is installed, these
voltage settings increase if the temperature around the BTS is <77°F (25°C),
and decrease if the temperature around the BTS is >77°F (25°C).
** The MMSA uses changeable settings (see Table 4-3) that are adequate
for most installations. However, if some of your operating parameters
need to be changed, the ME-MR, ME-RC, or ME-ARC remote control can be
purchased to allow change to those settings.