Operation
ProStar MPPT Operator’s Manual
41
40
4.0
Equalization Stage
WARNING:
Risk of Explosion
Equalizing vented batteries produces explosive gases.
The battery bank must be properly ventilated.
CAUTION:
Equipment Damage
Equalization increases the battery voltage to levels that
may damage sensitive DC loads. Verify all system loads
are rated for the temperature compensated Equalize
voltage before beginning an Equalization charge.
CAUTION:
Equipment Damage
Excessive overcharging and gasing 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 require-
ments for the particular battery being used in your system.
AVERTISSEMENT:
Risque d’explosion
Les batteries à évent et compensation produisent des gaz
explosifs. Le groupe de batteries doit être correctement
ventilé.
PRUDENCE:
Endommagement de l’équipement
La compensation augmente la tension des batteries à des
niveaux pouvant endommager les charges sensibles en
CC. Vérifiez que toutes les charges du système sont
conçues pour la tension de compensation par température
avant de commencer une charge de compensation.
PRUDENCE:
Endommagement de l’équipement
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.
Certain battery types benefit from a periodic boost charge
to stir the electrolyte, level the cell voltages, and complete
the chemical reactions. Equalization (EQ) charging raises
!
!
!
!
the battery voltage above the standard absorption voltage
so that the electrolyte gases. The green SOC LED will
blink rapidly two (2) times per second during equalization
charging. The duration of the equalize charge is determined
by the selected battery type. See table 4-1 in this section
for more details. The
Equalization Time
is defined as time
spent at the equalization set-point. If there is insufficient
charge current to reach the equalization voltage, the EQ
will terminate after an additional 60 minutes to avoid over
gasing or heating of the battery. If the battery requires
more time in equalization, with non-metered versions,
manual EQ can be activated using the push-button (see
Section 4.5) to continue for one or more additional EQ
cycles. The Prostar MPPT meter, or MSView software, can
also be used to program EQ timing and duration.
The Equalization set-point is temperature compensated
through either the on-board local temperature sensor, or an
optional Remote Temperature Sensor (RTS), if connected.
Why Equalize?
Routine equalization cycles are often vital to the perfor-
mance and life of a battery - particularly in a solar system.
During battery discharge, sulfuric acid is consumed and
soft lead sulfate crystals form on the plates. If the battery
remains in a partially discharged condition, the soft crystals
will turn into hard crystals over time. This process, called
“lead sulfation”, causes the crystals to become harder
over time and more difficult to convert back to soft active
materials. Sulfation from chronic undercharging of the bat-
tery is the leading cause of battery failures in solar systems.
In addition to reducing the battery capacity, sulfate build-up
is the most common cause of buckling plates and cracked
grids. Deep cycle batteries are particularly susceptible to
lead sulfation.
Normal charging of the battery can convert the sulfate back
to the soft active material if the battery is fully recharged.
However, a solar battery is seldom completely recharged, so
the soft lead sulfate crystals harden over a period of time.