Product Manual
48
SELFTESTING/DIAGNOSTICS
49
MORNINGSTAR CORPORATION
8.0
• Battery charging requires temperature compensation (connect a remote
temperature sensor)
• Load is too large and is discharging the battery
Not charging the battery
• DIP switch settings may be wrong (check each switch position carefully)
• TriStar has detected a fault
(indicated by sequencing LEDS, refer to Section 3.3)
• Solar circuit breaker or disconnect is open
• Reversed polarity connections at the solar terminals (TriStar will not detect
the solar array)
• Short circuit in the solar array has eliminated part of the array output
• Solar array is not providing enough current (low sun or fault in the array)
• Battery is failing and cannot hold a charge
Troubleshooting Load Control
No power to the load
• DIP switch settings may be wrong (check each switch position carefully)
• Controller is in LVD (check the LEDs)
• Load circuit breaker or disconnect may be open
• Check the load cables for continuity and good connection
• An over-temperature condition may have caused the load to be
disconnected
Troubleshooting Diversion Control
• Diversion load is too small so PWM reaches 99%
• Diversion load is burned out so PWM reaches 99%
• Diversion load is too large so TriStar faults on overcurrent
• An overtemperature condition may have caused the load
to be disconnected
• The RTS is not correcting for high or low temperatures
• Voltage drops between the TriStar and battery are too high
Still having problems? Point your web browser to http://www.
morningstarcorp.com for technical support documents,
FAQ’s, or to request technical support.
9.0 Battery Information
The standard battery charging programs in the TriStar controller, as described
in Section 4.2, are typical charging algorithms for three battery types:
• sealed (VRLA)
• flooded (vented)
• L-16 group
Other battery chemistries such as NiCad, or special voltages such as 36V, can
be charged using a custom charging algorithm modified with the PC
software. Only the standard TriStar battery charging programs will be
discussed here.
CAUTION: Never attempt to charge a primary (non-rechargeable) battery.
PRUDENCE : N’essayez jamais de charger une batterie primaire
(non-rechargeable).
All charging voltages noted below will be for 12V batteries at 25˚C.
9.1 Sealed Batteries
The general class of sealed batteries suitable for solar systems are called
VRLA (Valve Regulated Lead-Acid) batteries. The two main characteristics of
VRLA batteries are electrolyte immobilization and oxygen recombination. As
the battery recharges, gassing is limited and is recombined to minimize the
loss of water.
The two types of VRLA batteries most often used in solar are AGM and Gel.
AGM:
Absorbed Glass Mat batteries are still considered to be a “wet cell” because
the electrolyte is retained in fiberglass mats between the plates. Some newer
AGM battery designs recommend constant voltage charging to 2.45 volts/
cell (14.7V). For cycling applications, charging to 14.4V or 14.5V is often
recommended.
AGM batteries are better suited to low discharge applications than daily
cycling. These batteries should not be equalized since gassing can be vented
which causes the battery to dry out. There is also a potential for thermal
runaway if the battery gets too hot, and this will destroy the battery. AGM
batteries are affected by heat, and can lose 50% of their service life for every
8˚C (15˚F) over 25˚C (77˚F).
It is very important not to exceed the gas recombination capabilities of the
AGM. The optimum charging temperature range is from 5 to 35˚C (40 to 95˚F).
Gel:
Gel batteries have characteristics similar to AGM, except a silica additive
immobilizes the electrolyte to prevent leakage from the case. And like AGM,
it is important to never exceed the manufacturer’s maximum charging
voltages. Typically, a gel battery is recharged in cycling applications from
14.1V to 14.4V. The gel design is very sensitive to overcharging.
For both AGM and Gel batteries, the goal is for 100% recombination of
gasses so that no water is lost from the battery. True equalizations are never
done, but a small boost charge may be needed to balance the individual