Troubleshooting
56
900-0209-01-00 Rev A
Table 7 Troubleshooting
Symptom Remedy
Unit not operating;
unit had worked
normally before;
normal light
conditions
Check the charging stage. Check other controllers (if present). If the batteries are
nearly charged, one controller may taper off (in the Absorption or Float stage) while
the other(s) complete the charge.
High temperature fault. Check controller temperature (see page 38).
The FLEXmax 100 will stop functioning at an
Output FETs
reading of 90°C.
The system display
Over Temperature
error will indicate
Y
. (See page 38.)
High
V
oc
fault. Check PV array voltage. If the open-circuit voltage (V
oc
) is too
high, the controller cannot safely operate. The system display
VOC Too High
error
will indicate
Y
. (See page 38.) The FLEXmax 100 will automatically restart
operation once the V
oc
decreases to a safe level.
Upper limits: 24-volt system = 275 Vdc, 36-volt system = 283 Vdc, 48-volt system =
290 Vdc. See page 66 for more information.
CAUTION: Hazard to Equipment
Voltages in excess of 300 Vdc are likely to damage the FLEXmax 100.
The PV array should be designed to avoid ever reaching these voltages.
Unit not producing
expected power
Check PV and battery voltages. If they are varying widely, the controller may be in
the process of an MPPT sweep. It should settle on a stable power point and
produce normally again after a short time.
Check PV conditions. Clouds, shading, or dirty modules cause poor performance.
Check battery conditions and charging stage. If the batteries are charged (if the
controller is in the Absorbing or Float stage), the controller will produce only enough
power to regulate the voltage at those set points. Less power is required.
Determine the specified short-circuit current of the PV array. The MPP current is
related to this number. Use a multimeter to determine if the short-circuit current is in
the expected range. Array or wiring problems may restrict the available power.
Check the PV array temperature. At high temperatures, the maximum power point
voltage may be near or lower than the battery voltage.
Check FLEXmax 100 external temperature. The output is derated above ambient
temperatures of 25°C (77°F). Also check FLEXmax 100 internal temperature using
the system display. See page 38.
If a temperature reading is greater than 142°C or less than -40°C, a sensor may
have failed. The
Reduced Performance
error will show
Y
(see page 38).
NOTE
:
If the temperature is high, check the condition of the heatsink. This may
require dismounting the controller. If the heatsink is blocked with mud, organic
material, etc., the controller will not receive normal ventilation. Clean it by scraping
between the fins with a thin wooden stick. Spraying is not recommended.
Unit in equalization
cycle but not
achieving expected
results
Check equalization settings using the system display. (See pages 44 and 68). The
default settings are not sufficient for many batteries and may need to be adjusted.
The cycle will begin when the
Equalization Voltage
set point has been reached. A
small array or cloudy weather will delay the equalization cycle. Running too many
battery loads will also delay the
cycle. Loads should be removed or minimized.
Check the PV array temperature. At high temperatures, the maximum power point
voltage may be near or lower than the battery voltage. This can delay the
cycle.
Battery Calibration
setting does not
respond
The system display will not report this setting if remote battery sensing is connected.
To test this function, temporarily disconnect remote battery sensing. (See page 21.)
