HindlePower AT10.1, AT30, AT Operating Instruction
AT10.1/AT30 Series Battery Charger
JD5003-00 Application Note
USING THE OPTIONAL TEMPERATURE COMPENSATION FEATURE
SCOPE
all single phase AT10.1 and all three phase AT30 microprocessor-controlled float battery chargers
SUMMARY
The AT Series battery charger can use an optional battery sensor (A10) to compensate dc output voltage for
changes in temperature. This option (manufacturer's p/n EJ5033-##), also referred to as "TempCo", consists
of a probe (or "puck") and an interconnection signal cable.
TEMPERATURE EFFECTS ON STORAGE BATTERIES
Storage batteries used in stationary applications are normally charged at a constant "float" voltage. The float
current depends on electro-chemical processes in the battery that vary with battery temperature. This causes
the float current to change as the temperature changes. This is true especially for the two battery types most
commonly used in industry (lead-acid and nickel-cadmium).
When storage batteries are charged at constant voltage, float current increases with increases in ambient
temperature. For a 10 °C increase in temperature, the float current approximately doubles (the change may be
smaller for a nickel-cadmium battery). Expressed differently, float charge voltage required to maintain a
constant float current decreases as temperature increases. Thus, we say that the battery float voltage has a
negative temperature coefficient. In normal float operation, the float voltage is chosen so that the float current
exactly compensates for internal self-discharge. Maintaining the balance between float current and selfdischarge is an important element in realizing maximum battery life.
The AT series charger normally has a constant dc output "float" voltage. If the charger is connected to a
battery that sees wide temperature fluctuations, the average float current may not be the optimum value. The
AT charger can use an optional temperature probe, mounted on or near the battery, to monitor the battery
temperature. The charger control circuit uses the information from the temperature probe to change the float
voltage as temperature varies, with the goal of maintaining the float current at the correct value.
WHEN TO USE TEMPERATURE COMPENSATION
If your battery is installed in a temperature-controlled room, you probably do not need a temperaturecompensated battery charger, although you should adjust the float voltage correctly for the temperature in the
battery room. However, you might consider adding temperature compensation to the charger if you have any
of the following conditions:
If the battery is in a temperature-controlled environment, but there is a risk of failure or
disconnection of the environmental controls (e.g. air conditioning).
If the battery is a Valve-Regulated Lead Acid (VRLA) type, and the battery room may see
moderate temperature changes.
If the battery is in a non-temperature-controlled environment.
If a site requirement exists for SCADA system battery temperature monitoring. Refer to the AT
Series Communications Module Operating Instruction (JA0102-04
5.4.3 (Analog Input Point Index 9) or Modbus Section 6.3.3 (Input Register 30010) for details.
To order TempCo (option p/n EJ5033-0#) with a new AT Series charger, choose it from the list on the order
sheet, or specify it on your purchase order. To order it for field installation, order the TempCo field retrofit
kit suitable for your application from your sales representative. See also www.ATSeries.net
). See DNP3 Level 2 Section
.
INSTALLING TEMPERATURE COMPENSATION
A separate installation procedure (JA5015-00) is supplied with each TempCo kit. The procedure is the
same for all AT Series battery chargers, and whether you have a new charger or are installing TempCo into an
existing unit. In most cases, you may follow the steps outlined in the AT Series battery charger Operating
and Service Instructions, Section 1.11. The installation steps outlined in the AT30 manual are reprinted on
Page 5 of this application note (JD5003-00) for convenience. Substitute "AT10.1" for "AT30" as needed.
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AT10.1/AT30 Series Battery Charger
JD5003-00 Application Note
ADJUSTING FLOAT & EQUALIZE VOLTAGES WITH TEMPCO
Before setting the float and equalize voltages with the remote TempCo probe installed, it is a good idea to
verify that the front panel voltmeter is calibrated, as described in the Operating and Service Instructions,
Section 2.3.7. To do this:
Disconnect one wire from TB8. The error code E 08 will appear on the front panel meter display. To
get rid of the error, de-energize and restart the charger in Float mode.
Connect a digital dc voltmeter to the dc output terminals of the charger.
Press and hold the UP key, then press the EQLZ MTHD key. Release both keys. This places the
charger in the Voltmeter calibration mode. The front panel meter displays the output float voltage.
Press the UP or DOWN key repeatedly until the actual output voltage, measured by your external
digital voltmeter, matches the float voltage shown by the charger's front panel meter. The output
voltage increases or decreases by a small amount each time you press the key. You must press and
release the key once for each increment in output voltage; pressing and holding the key does not cause
the voltage to scroll.
Remember, it is the actual output voltage of the charger that changes when you press the UP or DOWN key,
and the charger's front panel meter stays the same. After you have calibrated the meter, remove your digital
voltmeter, de-energize the charger, reconnect the temperature probe wire to TB8, and restart the charger.
With the TempCo probe connected, working properly, under default factory settings, the front panel meter
always shows the float (or equalize) voltage for a 25°C (77°F) temperature. The actual output voltage of the
charger varies with temperature, such that the actual dc output voltage will almost never match the front
panel meter reading. The temperature probe should be installed in a location that is likely to produce a good
indication of the average temperature of the battery.
When adjusting the float and equalize voltages from the front panel, the displayed voltage is the value at
25°C. The temperature probe determines the actual dc output voltage of the charger. Be sure that the float
and equalize voltages that you set agree with the battery manufacturer's recommendations for 25°C (77°F)
operation.
If you know the probe temperature, you can adjust the float voltage for that exact temperature, using the graph
at the end of this application note. Since the probe has a temperature tolerance of ±0.5°C, you may want to
adjust the float and equalize voltages if they are more than about 1% off. Remember that any adjustment you
make has to be for the average temperature of the entire battery. Changing the float or equalize voltage
doesn't change the slope of the compensation; the change in dc output voltage vs. temperature will still be
correct.
COMPENSATED VS. UNCOMPENSATED
AT Series battery chargers equipped with newer Main Control PC Boards (A1), utilizing firmware Version
6.53 or higher, feature the ability to use either temperature-compensated or un-compensated dc voltages in its
operation and displays. Older boards may only use compensated voltages. Chargers with newer boards are
normally shipped from the factory set for using compensated voltages. Utilize this feature as follows:
Shut down the AT Series battery charger.
Properly install the TempCo probe and cable as defined on Page 5 of this document.
Set jumper (J30) on the Main Control PC Board (A1) to positions 2-3 to use compensated voltages.
or
Set jumper (J30) on the Main Control PC Board (A1) to positions 1-2 to use uncompensated voltages.
Restart the AT Series battery charger per Section 2.1 of the Operating and Service Instructions.
The Main Control PC Board (A1) will detect the installed remote TempCo probe, and the display will
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flash Pb (or nicd).
AT10.1/AT30 Series Battery Charger
JD5003-00 Application Note
Compensated (or firmware Version 6.52 or lower)
This is the default setting from the factory, and the only operation available on older units. If Jumper J30 is
set at the 2-3 position, the charger will operate using compensated voltages. The front panel meter will
display a dc voltage value modified for battery temperature. The displayed meter value will be different from
the actual charger dc output voltage, unless the battery is at the nominal temperature of 25°C (77°F).
The software alarm points (HVDC and LVDC) will move with temperature. If the float voltage is set at 131.0
and the HVDC alarm is set to 136.0, the HVDC alarm will not trip unless the output is 5 volts above the float
set-point. This means that if the actual charger dc output is at 135.0 due to temperature compensation, the
HVDC alarm will not trip until 140.0 actual output.
The hardware Low DC Voltage alarm is not affected by temperature compensation, and will always trip at
the same dc output voltage. This is the same as for the un-compensated setting.
If the remote TempCo probe circuit is shorted or opens while the charger is powered, an alarm code E 08 will
display on the front panel meter. If the probe circuit is open, and the charger is then shut down and re-
energized, there will be no error code upon start-up. Also, temperature compensation will not be active.
If AT Series Forced Load Sharing, see Operating Instructions (JA5054-00
must have remote TempCo probes attached. The probe on the master (LS-P) charger will cause the output to
be adjusted for temperature, while the probe on the slave (LS-S) charger will compensate the display and
alarm set points. Both chargers must have jumper (J30) in the same position, or the displays and alarms will
not match.
), is being used, both chargers
Uncompensated (available only on firmware Version 6.53 or higher)
If Jumper J30 is set at the 1-2 position, the charger will operate using un-compensated voltages. The front
panel meter will display the actual charger dc output voltage. The displayed meter value will not be the same
as the user-specified dc voltage set-point, unless the battery is at the nominal temperature of 25°C (77°F).
The software alarm points (HVDC and LVDC) will not move with temperature. The alarm set-points will
need to be raised or lowered sufficiently to allow for dc output voltage variations, due to temperature
compensation. NOTICE Using this feature, the default equalize setting of 139.0 will trip the default
HVDC alarm point of 144.0 when the temperature goes below 48°F on a lead-acid battery.
The hardware Low DC Voltage alarm is not affected by temperature compensation, and will always trip at
the same dc output voltage. This is the same as the compensated setting, or earlier firmware versions.
If the remote TempCo probe circuit is shorted or opens while the charger is powered, an alarm code E 08 will
display on the front panel meter. This code will replace the indicator for temperature compensation (Pb or
nicd). If the probe circuit is open, and the charger is then shut down and re-energized, there will be no error
code upon start-up. Also, temperature compensation will not be active.
If AT Series Forced Load Sharing, see Operating Instructions (JA5054-00
must have remote TempCo probes attached. The probe on the master (LS-P) charger will cause the output to
be adjusted for temperature, while the probe on the slave (LS-S) charger will compensate the display and
alarm points. The temperature compensation indicator (Pb or nicd) will alternate with the load share
indicator (LS-S or LS-P). Both chargers must have jumper (J30) in the same position, or the displays and
alarms will not match.
), is being used, both chargers
TEMPCO 'NUTS & BOLTS'
The temperature probe consists of a glass bead thermistor (temperature-dependent resistor) mounted in an
epoxy puck, with double-faced tape for mounting on a dry surface. While the adhesive is compatible with
a wide range of materials, it is optimized for high surface energy materials (most metals, for example). The
probe should not be mounted on plastic surfaces, including most battery jars. It can be mounted on leadplated or nickel-plated cell connectors, a battery rack, or enclosure wall. Inter-cell connectors are
recommended as the best place for probe-mounting. In a battery room with little air movement, the intercell connector will be closer to the actual battery internal temperature than the outside of a battery jar.
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