Outback Power Systems FLEXmax Extreme Owners Manual - Manual (Page 39)

MATE3 Screens
900-0150-01-00 Rev A 37
MPPT
The charge controller uses a maximum power point tracking (MPPT) algorithm which manipulates the output of
the PV array to harvest maximum wattage. Although this function is automatic, this menu allows the user to
adjust many of its parameters for special applications. See page 73.
Figure 38 MPPT
The MPPT Modes perform the following functions:
 Auto Track (default) automatically measures the PV upon wakeup and then tracks the array MPP. If Restart
Mode is set to 1 or 2, the controller awakens every 1.5 hours and does an initial tracking. (See page 70.)
 U-Pick allows the user to manually adjust the MPP tracking limit as a percentage of the array's open-circuit
voltage (V
oc
). U-Pick % acquires a new V
oc
value every 1.5 hours if Auto Restart is set to 1 or 2.
The Wakeup settings adjust the V
oc
conditions that cause the charge controller to wake up during “Sleep” or
“Snooze” operation. (See Table 3 on page 26.) Both settings may help adjust for varying conditions. Since
environmental conditions impact the open-circuit voltage of an array, the Wakeup VOC Change VDC can be
based on the last measured V
oc
value.
Before changing these values, monitor the system for a week or so using the factory defaults and then gradually
adjust the set points. If the set points are set too high, the charge controller might not wake up soon enough or
often enough, which means a loss of power production.
The Mpp Range settings adjust the upper range limit of the charge controller’s maximum power point (MPP)
tracking.
 The default Max MPP voltage limit is set at 90% of the V
oc
and should not normally be adjusted for a PV
array. If necessary, the adjustable limits are 80%, 85%, 90%, and 99% of the V
oc
.
 Min optimizes the tracking window for MPPT. The default setting of Half establishes the lower limit of this
window as one-half the V
oc
.
The Min range limit setting may be set to FULL if something other than a PV array is connected to the input of
the charge controller, such as a hydroelectric turbine (see page 73). However, the input voltage must never
exceed 150 Vdc at any time.
Set Points:
 MPPT Mode – Selects between Auto (which allows
automatic MPPT) and U-Pick (which limits the maximum
power point tracking to a specified voltage).
 U-Pick VOC% – The percentage of the open-circuit voltage
(V
oc
) used as the MPP tracking limit in U-Pick mode.
 Wakeup VOC Change VDC – The change in V
oc
which will
bring the controller out of “Sleep” or “Snooze” operation
regardless of Change Time. The controller will enter MPPT.
(The change in V
oc
means that power may be available).
 (Wakeup VOC) Change Time – The timer setting to leave
”Sleep” or ”Snooze” operation regardless of Change VDC.
The controller will enter MPPT. (It may re-enter “Snooze”
and restart the timer if no power is available).
 Snooze Mode Amps – The output current limit below which
the controller enters “Snooze” due to inactivity.
 MPP Range Minimum – Adjusts the lower limit of the
controller’s tracking algorithm. This can narrow the focus of
the initial tracking process.
 MPP Range Maximum – Sets the upper limit of the tracking
algorithm as a percentage of the V
oc
.