Alpha Technologies Cordex Controller Ver.3.1x - Manual (Page 11)

9 0700015-J0 Rev B
2.8.1 Theory of Battery Temperature Compensation
The battery life expectancy and performance is directly related to the battery ambient temperature. The
optimum battery temperature during operation is 25°C (77°F). Without compensation, battery life is seri-
ously compromised at temperatures above 25°C, while battery performance is reduced below 25°C.
Adjusting the battery’s float or equalize voltage to correspond with temperature fluctuations ensures
maximum battery performance and life expectancy. With the CXC, this can be accomplished by using
the software’s built-in automatic temperature compensation function. This function adjusts the system
voltage, ever 60 second, as the temperature changes and provides for a maximum voltage change of
0.1V over this interval.
Temp Comp occurs at standard rates commonly referred to as slope-compensation settings. For maxi-
mum performance, the battery slope compensation must be matched to the setting recommended by the
battery manufacturer. Do not confuse this with the slope regulation, which refers to the process of regulat-
ing the current among a group of parallel-operating rectifiers.
The Temp Comp feature uses programmable breakpoints, which are the points that Temp Comp ceases.
Further temperature decreases or increases do NOT increase or decrease the output voltage. This pro-
tects the connected load and battery from excessive voltages. As Temp Comp is active in either float or
equalize mode, set breakpoints with this in mind.
When temperature compensation is enabled in Equalize Mode, the CXC uses the equalize voltage setting
as the center point around which to make Temp Comp voltage adjustments.
When temperature compensation is enabled in Float Mode, the CXC uses the float voltage setting as the
center point around which to make Temp Comp voltage adjustments.
2.8.2 Operation of Battery Temperature Compensation
The CXC can accommodate up to four sensors that monitor lead acid battery temperatures. If more than
one sensor is used and the temperature readings are within 5°C (9°F) of one another, the temperature
readings are averaged. If the reading differences exceed 5°C, a thermal runaway is assumed in one
battery string and the reading changes from the average reading to the highest. If any reading suddenly
jumps outside the normal range (i.e. leads are cut or opened), that reading is discarded and the associ-
ated Temp Sensor Fail alarm is activated. The temperature reading then returns to the average for the
remaining sensors, or to the next highest reading.
Temp Comp has been programmed as a low priority item. All other commands and operations take
precedence over Temp Comp. If a command is issued during a Temp Comp cycle, the cycle will be put
on hold until the command is completed. If any operation is happening when the Temp Comp cycle oc-
curs, the cycle is put on hold until the operation is completed. Temp Comp resumes when the command
or operation completes. The Temp Comp feature can be enabled or disabled in the CXC Batteries menu
(“6.5.1 Temperature Compensation” on page 50.
2.9 Battery Auto Equalization
Auto Equalize (Auto-EQ) is a protective feature designed to ensure optimal lead acid battery life and per-
formance. With the CXC, auto equalize is used for two basic purposes: (1) for providing a quick battery
recharge after an AC power failure, and (2) as a long-term battery maintenance feature.
Refer to the battery manufacturer’s recommendations for equalization charging.
2.9.1 Battery Charge Auto Equalize
Battery Charge Auto Equalize can be used after a prolonged AC power failure when the battery voltage
has decreased to a low level.
Once battery voltages have decreased below the auto equalize low voltage threshold, the CXC enters an
armed mode. When AC power returns, the system voltage begins to increase and charges the batteries.
Once the system voltage increases to the high voltage threshold, the CXC enters the equalize mode
and begins to equalize the battery charges for a period specified by the Supervisor in the AUTO-EQ
DURATION submenu. This is done to ensure the EQ duration is not effectively reduced by the time it
takes to recharge the battery to the nominal system voltage.