45
TriStar MPPT 600V Operator’s Manual
44
Operation
Float Stage
After the battery is fully charged in the Absorption stage, the TriStar MPPT 600V reduces the
battery voltage to the Float voltage set-point. When the battery is fully recharged, there can be
no ore c e ica reactions an a t e c ar in c rrent is t rne into eat an
assin
e oat
stage provides a very low rate of maintenance charging while reducing the heating and gasing of
a
c ar e
atter
e
r ose o oat is to rotect t e atter ro
on ter o erc ar e
The green SOC LED will blink once every two (2) seconds during Float charging.
Once in Float stage, loads can continue to draw power from the battery. In the event that the
system load(s) exceed the solar charge current, the controller will no longer be able to maintain
the battery at the Float set-point. Should the battery voltage remain below the Float set-point for
a cumulative 60 minute period, the controller will exit Float stage and return to Bulk charging.
The Float set-point is temperature compensated if the RTS is connected.
Equalize 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 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.
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 atter t es enefit ro a erio ic oost c ar e to stir t e e ectro te e e t e ce o t
-
ages, and complete the chemical reactions. Equalize charging raises the battery voltage above
the standard absorption voltage so that the electrolyte gasses. 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 efine as ti e s ent at t e e a i e
set oint
t ere is ins ficient c ar e c rrent to reac t e e a i ation o ta e t e e a i ation
will terminate after an additional 60 minutes to avoid over gassing or heating the battery. If the
battery requires more time in equalization, an equalize can be requested using the TriStar Meter
or pushbutton to continue for one or more additional equalization cycles.
The Equalize set-point is temperature compensated if the RTS is connected.
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
i e is to e a i e oo e
atteries e er
to
ont s or e er
to
ee
isc ar es
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
or an e a i ation
it er t e s ecific ra it or t e ce o ta e can e eas re
e atter
an act rer can reco
en t e s ecific ra it or o ta e a es or o r artic ar atter
Why Equalize?
Routine equalization cycles are often vital to the performance and life of a battery - particularly in
a solar system. During battery discharge, sulfuric acid is consumed and soft lead sulfate crys-
tals 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
eco e ar er o er ti e an
ore i fic t to con ert ac to so t acti e ateria s
Sulfation from chronic undercharging of the battery 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 bat-
tery is fully recharged. However, a solar battery is seldom completely recharged, so the soft lead
sulfate crystals harden over a period of time. Only a long controlled overcharge, or equalization,
at a higher voltage can reverse the hardening of sulfate crystals.