Product Manual

32
SOLAR BATTERY CHARGING
33
MORNINGSTAR CORPORATION
4.04.0
cell. The overall battery voltage is 28.8V, but the individual cells are higher or
lower due to cell drift. Equalization cycles help to bring all the cells to the
same voltage.
Mix the electrolyte.
In flooded batteries, especially tall cells, the heavier acid will fall to the
bottom of the cell over time. This stratification of the electrolyte causes loss
of capacity and corrosion of the lower portion of the plates. Gassing of the
electrolyte from a controlled overcharging (equalization) will stir and remix the
acid into the battery electrolyte.
NOTE: Excessive overcharging and gassing too vigorously can damage the battery
plates and cause shedding of active material from the plates. An equalization that is
too high or for too long can be damaging. Review the requirements for the
particular battery being used in your system.
REMARQUE : Une surcharge excessive et un dégagement gazeux trop vigoureux
peuvent endommager les plaques de batteries et provoquer l’élimination du
matériau actif des plaques. Une compensation trop élevée ou trop longue peut
provoquer des dégâts. Examinez les exigences pour la batterie particulière utilisée
dans votre système.
4.4.1 Standard Equalization Programs
Both automatic and manual equalizations can be performed using either the
standard charging programs
(see 4.2) or a custom program (see 7.0) .
Manual Equalization
The TriStar is shipped with the DIP switch set for manual equalization only.
This is to avoid an unexpected or unwanted automatic equalization. In the
manual mode, the pushbutton is used to both start or stop a manual
equalization. Hold the pushbutton down for 5 seconds to start or stop an
equalization (depending on whether an equalization is in progress or not).
The LED’s will confirm the transition (all 3 LED’s blink 2 times). When the
battery charging enters into equalization, the Green LED will start fast
blinking 2-3 times per second.
There are no limits to how many times the pushbutton can be used to start
and stop equalizations. Equalizations will be terminated automatically per the
charging program selected if the pushbutton is not used to manually stop the
equalization.
Automatic Equalization
If the equalization DIP switch is moved to the ON position (see 2.3 - Step 3) ,
the equalizations will begin automatically per the charging program selected.
Other than starting, the automatic and manual equalizations are the same
and follow the standard charging program selected. The pushbutton can be
used to start and stop equalizations in both the manual and automatic mode.
4.4.2 Typical Equalizations
The automatic equalizations will occur every 28 days (except L-16 cells at
14 days). When an equalization begins (auto or manual), the battery charging
voltage increases up to the equalization voltage (Veq). The battery will remain
at Veq for the time specified in the selected charging program
(see table in 4.2) .
If the time to reach Veq is too long, the maximum equalization cycle time will
end the equalization. A second manual equalization cycle can be started with
the pushbutton if needed.
If the equalization cannot be completed in one day, it will continue the next
day or days until finished. After an equalization is completed, charging will
return to PWM absorption.
4.4.3 Preparation for Equalization
First, confirm that all your loads are rated for the equalization voltage. Consider that
at 0˚C (32˚F) the equalization voltage will reach 16.05V in a 12V system (64.2V in a
48V system) with a temperature sensor installed. Disconnect any loads at risk.
If Hydrocaps are used, be sure to remove them before starting an equal-
ization. Replace the Hydrocaps with standard battery cell caps. The Hydro-
caps can get very hot during an equalization. Also, if Hydrocaps are used,
the equalization should be set for manual only (DIP switch #7 is Off).
After the equalization is finished, add distilled water to each cell to replace
gassing losses. Check that the battery plates are covered.
4.4.4 When to Equalize
The ideal frequency of equalizations depends on the battery type (lead-calcium,
lead-antimony, etc.), the depth of discharging, battery age, temperature, and other
factors.
One very broad guide is to equalize flooded batteries every 1 to 3 months
or every 5 to 10 deep discharges. Some batteries, such as the L-16 group,
will need more frequent equalizations.
The difference between the highest cell and lowest cell in a battery can also
indicate the need for an equalization. Either the specific gravity or the cell
voltage can be measured. The battery manufacturer can recommend the
specific gravity or voltage values for your particular battery.
4.4.5 “Equalize” a Sealed Battery?
The standard battery charging table (see Section 4.2) shows two sealed batteries
with an “equalization” cycle. This is only a 0.05 volt (12V battery) boost cycle to level
individual cells. This is not an equalization, and will
not vent gas from sealed batteries that require up to 14.4V charging (12V
battery). This “boost” charge for sealed cells allows for adjustability with
the PC software.
Many VRLA batteries, including AGM and gel, have increased charging
requirements up to 14.4V (12V battery). The 0.05V boost shown in the
table (Section 4.2) is less than the accuracy range of most charge controllers.
Alternatively, for these two sealed battery charging programs you may prefer
to consider the PWM absorption stage to be 14.2V and 14.4V (12V battery).
The 14.0, 14.2, and 14.4 volt standard charging programs should be suitable
for most sealed batteries. If not optimum for your battery, the PC software