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+24 VDC Power System User Manual (Section 6013)
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Rev. G
56
The Automatic Equalize feature is a time based function which is controlled by a customer selectable multiplier
and by the Battery on Discharge (BOD) alarm setpoint. The MCA’s default setting is for a multiplier of zero,
which disables the Automatic Equalize feature.
When the Automatic Equalize feature is enabled, if system voltage drops to less than the BOD alarm setpoint,
the MCA initiates a timing cycle to measure the discharge time period. The MCA requires at least 15 minutes of
continuous BOD alarm in order to prevent nuisance equalization cycles. When system voltage rises to above
the BOD alarm setpoint, the MCA ends the discharge timing cycle and (assuming a minimum of 15 minutes has
elapsed) places the Rectifier Modules into the equalize mode for a customer selectable multiple of the
discharge time period (the discharge time period includes the initial 15 minutes).
The equalize time period can be set for 0 to 15 times the discharge time period, up to a maximum of 300 hours.
A zero (0) setting disables the feature.
When the Automatic Equalize feature is enabled, the MCA prevents a user from setting the equalize value lower
than the float setpoint. If the equalize value is set first, the MCA automatically sets the Automatic Equalize
Multiplier to zero (0), disabling the feature.
Manually setting the system to float or equalize mode cancels the automatic function, if active.
NOTE!
Equalization is only effective if the correct multiplier is entered to allow the battery to charge to
capacity. It makes no sense to end the equalize cycle before battery capacity has been restored. To
determine the multiplier, load current and system capacity must be known. For example, consider a
system with 200 amps of Rectifier Module capacity and 150 amps of load. If there is a 2 hour outage of
AC power, 300 amp-hours (150 x 2) will be drained from the battery. When AC power is restored, the
battery charge current will be 50 amps (200-150), and it will take at least 6 hours (300/50) to replace
the battery capacity. In this scenario, the multiplier must be set greater than 3 for the Automatic
Equalize feature to have any effect.
Enabling and Disabling the Automatic Equalize Feature: To enable, set the "AUTO EQ MUL = ##" menu
item in the MCA Configure Menu to a value between 0 and 15. To disable, set the "AUTO EQ MUL = ##" menu
item in the MCA Configure Menu to 0. A step-by-step procedure is provided next.
1.
With "SYSTEM OK" being displayed on the MCA Interface Pad, press and release the FUNCTION SET
ENTER pushbutton.
or
With "## ALARMS ACTIVE" being displayed on the MCA Interface Pad, press and release the
FUNCTION SET ENTER pushbutton. Repeatedly press and release the FUNCTION SELECT DOWN
arrow pushbutton until "FUNCTION MENU" is displayed. Press and release the FUNCTION SET ENTER
pushbutton.
2.
Repeatedly press and release the FUNCTION SELECT DOWN arrow pushbutton until "CONFIGURE
MENU" is displayed.
3.
Press and release the FUNCTION SET ENTER pushbutton.
4.
Repeatedly press and release the FUNCTION SELECT DOWN arrow pushbutton until "AUTO EQ MUL =
##" or "AUTO EQ DISABLED" is displayed.
