Outback Power Systems FLEXmax 80 Owners Manual - Manual (Page 24)

Operation
22 900-0009-01-00 Rev C
EX-Absorb
There is an external DC source other than PV keeping the battery above the Absorbing voltage set
point. The FLEXmax will stop charging because it is not needed.
Floating
The FLEXmax is in the Float stage of a three-stage cycle, regulating the battery voltage at the Float
voltage set point. This stage is temperature compensated. (See page 97.) If the battery voltage drops
below the Float voltage, the FLEXmax will employ the MPPT function to draw more power from the
PV array. (This may occur if the batteries are powering loads.) If this happens, the operating mode will
change to MPPT Float. (See below.)
GT Mode
The FLEXmax is in Grid-Tie mode. In a system with an OutBack grid-interactive inverter, a HUB, and a
system display, the FLEXmax will display GT Mode, if and only if, the inverter is in Sell mode and the
FLEXmax is in the MPPT BULK or MPPT FLOAT modes. This message also indicates that Grid-Tie mode
communication has been established between the inverter and charge controller. GT must be
selected in the MPPT Mode advanced menu in order to be viewed. (See page 47.)
High Voc
This indicates the PV array’s open-circuit voltage is too high for the controller to safely operate
(> 145 Vdc). This should only occur with systems using 72 Vdc nominal PV arrays in very cold
temperatures (below -15°C / 5°F). The FLEXmax will automatically restart operation once the PV
array’s open-circuit voltage falls to a safe level (145 Vdc or lower).
CAUTION: Equipment Damage
Voltages in excess of 150 Vdc are likely to damage the FLEXmax controller. The PV array
should be designed to avoid ever reaching these voltages.
Low Light or Snoozing
A Low Light or Snoozing mode indicates that the PV voltage is high enough to activate the FLEXmax,
but there is not enough current available to charge. During the initial tracking (see Wakeup and
Tracking), if it is determined to be too late (or too early) in the day, the FLEXmax will display Low Light
for a few seconds and then display Snoozing for five minutes (default). This reduces energy usage and
unnecessary powering of the FLEXmax. This message is also displayed in extremely cloudy weather.
MPPT Bulk
This is a Maximum Power Point Tracking mode which harvests the maximum wattage available from
the PV array. The controller is trying to regulate the battery voltage towards the Absorbing voltage
set point. Normally the charge controller enters this mode at the beginning of the day or when a new
charge cycle begins. The controller may also enter this stage if there is not enough PV energy to
maintain a different stage, such as Absorbing. See page 20 for more information.
MPPT Float
This is a Maximum Power Point Tracking mode which harvests the maximum wattage available from
the PV array. The controller is trying to regulate the battery voltage towards the Float voltage set
point. Normally, the charge controller enters this mode if it was in the Floating mode (see above) and
there was not enough energy to maintain the battery voltage.