5.0
Operation
44
GenStar MPPT
45
Figure 5.1. Nominal 12 volt solar module I-V curve and output power graph
5.2 GenStar MPPT Charging
The GenStar MPPT system batteries will have different charging requirements based on application,
mode of operation, season, usage schedules, load profile, etc. The GenStar MPPT’s charging algorithms
and settings have the capability to provide optimal charging, with flexibility for very specific demands.
The charger also offers easy to use preset profiles that will facilitate good battery health.
5.2.1 Charging Algorithms
Charging is completely adjustable to accommodate a variety of battery chemistries. The GenStar MPPT
offers a 5-stage battery charging algorithm for rapid, efficient, and safe battery charging. Figure 5-2,
below, shows the sequence of stages. The first charging phase is the
Battery Recharge Cycle
that
includes the Bulk, Absorption, Float, and Equalization stages. This cycle typically takes several hours to
complete.
NIGHT
BULK
CHARGING
ABSORPTION
FLOAT
EQUALIZE
VOL
TAGE
TIME
OPTIONAL
STAGE
Figure 5-2. GenStar MPPT 4-stage charging algorithm
PO
WER
VOLTAGE
10
15 17
TrackStar
Maximum
Power
Point
Traditional
Controller
Operating Range
CURRENT
VOLTAGE
10
15 17
Maximum
Power
Point
Typical Battery
Voltage Range
12 Volt Module
Current vs. Voltage
12 Volt Module
Output Power
5.2.2 Charging Profiles
GenStar MPPT offers eight (8) preset battery charging profiles, as seen in Tables 5-1 below. These
standard charging settings are suitable for lead-acid batteries ranging from sealed (gel, AGM,
maintenance-free) to Flooded and Lithium cells. All voltage settings listed are for nominal 12 Volt
batteries. Multiply the voltage settings by two (2) or (4), for 24 and 48 Volt systems, respectively.
NOTE:
These settings are general guidelines for use at the operator’s discretion. The
GenStar MPPT can also be customed programmed to satisfy a wide range of charging
parameters. Consult the battery manufacturer for optimal battery charge settings.
Table 5-2 shows all preset high voltage disconnect and reconnect settings. Table 5-3 shows the
shared settings that are common to all GenStar charging presets. Table 5-4 is a list of preset LVD-LVR
(Load Control disconnect-reconnect) profiles that also shows current compensation values. Any Load
Control preset can be added to a battery charging profile.
Table 5-1. GenStar MPPT Preset Charging Settings
CHARGING PRESET NOTES:
1
For Presets 2-5, an equalization charging stage can be initiated manually using the Start Equalization
Command from the local meter or LiveView. Auto equalization can only be set up using custom settings.
2
CAUTION: LiFePO4 settings are for 4, 8 and 16-cell LiFePO4 batteries only.
• Preset temperature compensation co-efficient for sealed or flooded batteries = -30 Millivolts / °C / 12V
-- temp. comp. is disabled for LiFePO4 presets.
• All settings, including charging stage voltages and timing, can be custom programmed using the local
meter or LiveView. LiveView includes additional advanced custom programming options.
• CAUTION: Equipment Damage
Do not equalize sealed batteries with preset or custom settings unless recommended by the battery
manufacturer. To prevent the possibility of unintended equalization, use custom settings to disable all
equalization.
• CAUTION: Settings may not be compatible with all models of these battery types.
• All voltage setting values are for 12V systems. Mutiply values by two (2) for 24 Volt batteries, or by four
(4) for 48 Volt systems.
GenStar MPPT Preset Charging Profiles
(@ 25°C)
Battery Type-Preset
Volts
Volts
Volts
Minutes
Minutes
Minutes
1 - Sealed
14.1
13.7
Disabled
150
Disabled
Disabled
2 - Sealed
14.3
13.7
14.6
1
150
60
120
3 - Sealed / Flooded
14.5
13.6
15.0
1
180
60
120
4 - Sealed / Flooded
14.6
13.5
15.2
1
180
120
180
5 - Sealed / Flooded
14.8
13.5
15.4
1
180
120
180
6 - LiFePO4 - Low
2
13.6
13.5
Disabled
180
Disabled
Disabled
7 - LiFePO4 - Medium
2
13.9
13.5
Disabled
20
Disabled
Disabled
8 - LiFePO4 High
2
14.2
13.5
Disabled
15
Disabled
Disabled
Equalization
Timeout
Absorption
Voltage
Float Voltage
Equalization
Voltage
Absorption
Time
Equalization
Time
