Sunforce Wind Power Notice D'utilisation page 8

charging regulation voltages. The MPPT charging regulation stages correspond to the chart
below.
Bulk: This stage provides the maximum power to the battery -- voltage increases while charging.
A bulk charge is automatically initiated when the battery voltage is below the absorb and float
voltage set points. The bulk charge will continue until the absorb voltage set point is achieved.
Absorbing: This stage limits the amount of power going to the battery -- the voltage is held
constant. The absorb charge will continue for the duration of the bulk cycle or until the 2 hour
(default) absorb time limit is reached. Example, if a bulk charge takes 1 hour to reach the absorb
voltage set point then the absorb charge will continue for 1 hour as well. However, if a bulk
charge takes 3 hours to reach the absorb voltage set point then the absorb charge will last for 2
hours only. A bulk charge will be re-initiated if the battery voltage is not sustained at the absorb
voltage set point.
Float: This stage reduces the charging voltage to prevent overcharging of the batteries
A float charge follows after the absorb charge is completed. The MPPT will not re-initiate
another bulk charge if the float voltage set point is not sustained, however, it will continue to
charge the battery until the float voltage set point is achieved. Note: A bulk charge can be
initiated if the battery voltage falls below the float voltage set point if the re-bulk (ReBV) voltage
option is set.
Understanding the various modes:
The modes of operation will change occasionally during the day based on turbines output and
battery system state of charge. The MPPT operating modes are displayed through the LED's.
Sleeping happens when the wind turbine's voltage is less than the battery voltage or charger
current is below the minimum cutoff (Low cutoff) current. This may also appear briefly during the
day when the MPPT is transitioning between certain states, and because of other conditions.
Wakeup As the turbine's open circuit voltage (Voc) rises above the battery bank's voltage by
approximately 2 volts, the MPPT controller gets ready to work to deliver the best possible power
to the batteries. During this period, the MPPT is calculating the PWM (Pulse-width modulation)
duty cycles by turning on power supply voltages in the proper sequences, and making internal
calibrations. At wakeup, the MPPT closes its relays and will then start sweeping the input voltage,
(the "initial" sweep), towards the battery voltage. This may happen numerous times at both dawn
and dusk until there is enough power from the turbine to keep charging the battery bank. Wakeup
is also a time when the MPPT controller acquires a new Voc.
Sweeping In Auto-Sweep MPPT mode, the MPPT is either doing an initial sweep of the turbines
voltage from Voc towards battery voltage after wakeup, or is doing a periodic dithering mini-
sweep to stay on the max power point. Below 5 amps of battery output current, this will flash
briefly as the MPPT operates at the Park MPP voltage. This signal may also appear briefly if the
MPPT has reached the max battery current setting and is raising the turbines operating voltage to
keep the battery current from exceeding the maximum battery output current limit setting.
Absorb There is an external DC source (wind generator/hydro) keeping the battery at or above
the absorb set point.
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