5.0
GenStar MPPT
43
Configuration
42
Figure 4-3. External Source Control Setup Sequence
4.2.9 Local Meter Display and Button
(Setup and Installer Setup)
The
Meter Display
can be used to:
1) Adjust screen appearance and functionality - see Figure 4-1, Display and Button Branch for
details.
2) Map-program
Soft-key
commands for momentary press and press and hold -- hold time is >2
seconds.
4.2.10 Save and Load
(Setup and Installer Setup)
To
Save
settings to a PC or an SD Card, enter a filename and use the Save button for the preferred
location.
Load
settings from a PC or an SD Card by choosing a file and then clicking on the Load
button. Use the
View
button to review a summary of the file settings
before loading.
ReadyBlocks
ESC Schedules
ESC Conditions
ESC Schedules Composite Example
INSTALLER SETUP
GO TO
STEP 1
STEP 2
STEP 3
Select Relay Block
to configure
Select relay A or B
Start Charging 1
Start Charging 2
Start Charging 3
Pause Charging
Prohibit Charging
Assign to ESC Start
-Stop
Define Relay Signal
Define Start - Stop
Criteria
Enter daily and
weekly timing into
schedules
EXTERNAL SOURCE CONTROL (ESC) SETUP SEQUENCE
Emergency Charging
Start Charging 1
Start Charging 2
Start Charging 3
Pause Charging
Emergency Charging
Sch. 1
Sch. 2
Sch. 3
Sch. 4
Time 12:00 1:00 2:00 3:00 4:00 5:00 6:00
EXAMPLE NOTES - and precedence for conflicts:
1. Thicker
segment represents higher priority
2. Sch. 4 in effect from 12-3 and 4-5
3. From 3-3:30, Sch. 1 takes precedence over
Schs. 3 and 4
4. From 3:30-4:00, Sch. 3 takes precedence
5. From 5-6, Sch. 2 takes precedence
5.1 TrakStar
TM
MPPT Technology and Charging
The GenStar MPPT utilizes Morningstar’s TrakStar Maximum Power Point Tracking technology to
extract maximum power from the solar module(s). The tracking algorithm is fully automatic and does
not require user adjustment. Trakstar technology will track the array maximum power point voltage
(Vmp) as it varies with weather conditions, ensuring that maximum power is harvested from the array
through the course of the day.
Current Boost:
In many cases, TrakStar MPPT technology will “boost” the solar charge current. For example, a
system may have 2 amps of solar current flowing into the GenStar MPPT and five amps of charge
current flowing out to the battery. The GenStar MPPT does not create current! Rest assured that the
power into the GenStar MPPT is the same as the power out of the GenStar MPPT. Since power is the
product of voltage and current (Volts x Amps), the following is true*:
(1) Power Into the GenStar MPPT = Power Out of the GenStar MPPT
(2) Volts In x Amps In = Volts Out x Amps Out
* assuming 100% efficiency i.e. if no losses in wiring and conversion existed.
If the solar module’s Vmp is greater than the battery voltage, it follows that the battery current must
be proportionally greater than the solar input current so that input and output power are balanced.
The greater the difference between the maximum power voltage and battery voltage, the greater
the current boost. Current boost can be substantial in systems where the solar array is of a higher
nominal voltage than the battery as described in the next section.
High Voltage Strings and Grid-tie Modules
Another benefit of TrakStar MPPT technology is the ability to charge 12 or 24 volt batteries with
solar arrays of higher nominal voltages. A 12 volt battery bank can be charged with a 12, 24, 36
or 48V nominal off-grid solar array. Certain grid-tie solar modules may also be used as long as the
solar array open circuit voltage (V
oc
) rating will not exceed the GenStar MPPT 200V maximum input
voltage rating at worst-case (lowest) module temperature. The solar module documentation should
provide V
oc
vs. temperature data.
Higher solar input voltage results in lower solar input current for a given input power. High voltage
solar input strings allow for smaller gauge solar wiring. This is especially helpful for systems with long
wiring runs between the solar array and the GenStar MPPT.
An Advantage Over Traditional Controllers
Traditional controllers connect the solar module directly to the battery when recharging. This requires
that the solar module operate in a voltage range that is below the module’s V
mp
. In a 12V system,
for example, the battery voltage may range from 10 - 15 Vdc but the module’s V
mp
is typically around
17V. Figure 5.1 - below - shows a typical current vs. voltage output curve for a nominal 12V off-grid
module.
5.0 OPERATION
