Transition voltage V12 is reached and the charger indicates that it is now
in the second stage of charging; equalize. The charger is now charging at a constant
Battery voltage approaches the equalize level
(VE) and the charge current
begins to taper.
Charge current tapers to
IET. The charger senses the drop in current as
the battery becomes fully charged, and changes to the third stage; float. The battery
voltage is held at VF.
Here, a load (greater than I max) begins to discharge the battery.
The load discharges the battery, causing the voltage to fall below V31.
The charger is now in the bulk rate again.
The Series 9650 chargers allows the technician in the field to
adjust the set points for different battery types (NCad. and lead acid) and amp hour
capacities. The following parameters are adjustable:
Maximum current output ( I max)
Float voltage (VF) Equalize current termination
(IOCT)-also referred as overcharge state.
Upon adjusting the above parameters, the following points are
The automatic application of equalize and float
charging ensures the battery is brought up to full charge with the minimum amount of water
loss, or gassing. Temperature compensation is one of the most important features,
providing optimum charging during changes in the environment. These charging features
greatly improve the life and reliability of using NCad. sealed and maintenance fee
National Electric Codes (NEC) requirements are met with the elimination
of the diode or transistors in the negative circuit. Current sensing is in the positive
circuit and galvanically isolated. A short in the negative circuit external to the charger
will not affect the current control.
The output current is controlled and the voltage is regulated; however,
should these circuits fail, a relay within the charger will open the circuit to the
battery. The same relay is used to help prevent system damage if the battery is connected
with reverse polarity.
The Series 9650 chargers are available with either a terminal strip or
connector. Using a connector improves safety and reliability because there are no exposed
terminals which can accidentally become shorted, and the connections are shielded against
Corrosion resistant, hard anodized aluminum cover and chassis, equipped
for rack, table, or wall mounting The enclosure is sealed and weather resistant. The
control panel consists of digital volt and amp meters, input power, on/off circuit
breaker, battery on/off circuit breaker, and operational LED monitors.
Series 9650 Alarms and Protection Features:
Over-voltage. Should output voltage rise above a factory preset level, the controller
will disconnect the battery from the controller via an internal relay. A visual LED alarm
is provided in the front panel. Alarm Relay is triggered. This circuit failure will
require manual reset, by switching off input power.
Over-current. Should the output current raise above a factory preset level, the
controller will disconnect the battery from the controller via an internal relay. A visual
LED alarm is provided in the front panel. Alarm Relay is triggered. This circuit failure
will require manual reset, by switching off input power.
No Load. The charger monitors the output current to make sure that there is a battery
and load connected. This set point is field connected. A visual LED alarm is provided and
the Alarm Relay is triggered. Alarm condition is automatically reset when the circuit
senses the load. False alarms can occur when there is a small load and the charger
switches from equalize to float. When charging at equalize (overcharge) battery is brought
to a high potential; switching to float, which is at a lower potential, creates a short
term condition where the battery potential is higher than the charger output. No current
can flow from the charger creating the alarm condition. As the battery voltage decays to
the float voltage the alarm goes away.
Low-Voltage Load Disconnect. This feature disconnects the load to protect the battery
from being over-discharged. The disconnect point is field adjustable. The load reconnects
automatically after the battery voltage climbs 3-4 volts above the disconnect setting.
Remote temperature sensor. This sensor monitors the battery temperature and adjusts the
float voltage for optimum charging. The sensor incorporates a thermister. Any changes to
the cable length or the incorporation of terminals or connectors will require
recalibration of the float voltage.
The Models 9650DC and 9650AC are fully automatic
chargers. No operator intervention is required once calibrated and installed. Other than
calibration every two years, there is no maintenance.
Due to the reverse polarity circuit and relay, it is important to:
- connect the battery
- close the battery circuit breaker/switch
- close the input (power) circuit breaker.