Operation
900-0198-01-00 Rev A
23
Equalization
Equalization is a controlled overcharge that is part of regular battery maintenance. Equalization brings the
batteries to a much higher voltage than usual and maintains this high voltage for a period of time. This
has the result of removing inert lead sulfate compounds from the battery plates. It also reduces
stratification by circulating the electrolyte.
Equalization follows the same pattern as standard three-stage charging, as shown in the figures on page
19. However, instead of the Absorption voltage and time set points, it is controlled by the
Equalize
Voltage
and
Equalize Time
settings in the system display.
This process must be started manually using the system display. The inverter cannot be programmed for
automatic battery equalization. This is a safety measure.
Equalization is normally performed only on flooded lead-acid batteries. The schedule for equalization
varies with battery use and type, but it is usually performed every few months. If performed correctly, this
process can extend battery life by a considerable amount.
Equalization is not normally performed on nickel-technology batteries or any sort of sealed battery.
CAUTION: Battery Damage
Do not equalize OutBack EnergyCell batteries of any model.
Do not equalize any sealed battery types (VRLA, AGM, Gel, or other) unless
approved by the manufacturer. Some batteries may suffer severe damage
from equalization.
Contact the battery manufacturer for recommendations on equalization
voltage, duration, schedule, and/or advisability. Always follow
manufacturer recommendations for equalization.
Battery Temperature Compensation
Battery performance will change when the temperature varies above or below room temperature (77°F or
25°C). Temperature compensation is a process that adjusts battery charging to correct for these changes.
When a battery is cooler than room temperature, its internal resistance goes up and the voltage changes
more quickly. This makes it easier for the charger to reach its voltage set points. However, while
accomplishing this process, it will not deliver all the current that the battery requires. As a result, the
battery will tend to be undercharged.
Conversely, when a battery is warmer than room temperature, its internal resistance goes down and the
voltage changes more slowly. This makes it harder for the charger to reach its voltage set points. It will
continue to deliver energy as time passes until the charging set points are reached. However, this tends to
be far more than the battery requires, meaning it will tend to be overcharged.
The FX inverter, when equipped with the Remote Temperature Sensor (RTS) will compensate for changes
in temperature. The RTS is attached to a single battery near the center of the bank, to achieve a
representative temperature. The FX inverter has a designated port for installing the RTS.
If installed in a multiple-inverter system, only a single RTS is necessary. It must be plugged into the master
inverter and will automatically control the charging of all slaves and all charge controllers.
When charging, an inverter system with an RTS will adjust the charging voltage inversely with changes in
temperature. It will
increase
the charge voltage by 5 mV for every decrease of 1 degree Celsius per
battery cell. Similarly, it will
decrease
the voltage 5 mV for every increase of 1 degree Celsius per cell.
