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How to troubleshoot the GP-PWM Solar Charge Controller 10-SQ
Problems with the Display
Display Reading: Blank | Time of Day: Day / Night
Possible Cause:
(1) Battery or fuse connection and/or solar array connection (Daytime only).
(2) Battery or fuse connection (Night only).
How to tell:
(1) & (2) Check the voltage at the controller battery terminals with a voltmeter and compare with a voltage reading at the battery terminals. If there is no voltage reading at the controller battery terminals, the problem is in the wiring between the battery and controller. If the battery voltage is lower than 6 volts the controller will not function. For the solar array, repeat steps 1 and 2 substituting all battery terminals with solar array terminals.
Remedy:
(1) & (2) Check all connections from the controller to the battery including checking for correct wire polarity. Check that all connections are clean, tight, and secure. Ensure the battery voltage is above 6 volts. Check the condition of the fuse.
Problems with Voltage
Voltage Reading: Inaccurate | Time of Day: Day / Night
Possible Cause:
(1) Excessive voltage drop from batteries to controller due to loose connections, small wire gauge or both.
How to tell:
(1) Check the voltage at the controller battery terminals with a voltmeter and compare with the voltage reading at the battery terminals. If there is a voltage discrepancy of more than 0.5 V, there is an excessive voltage drop.
Remedy:
(1) Check all connections from the controller to the battery including checking for correct wire polarity. Check that all connections are clean, tight, and secure. Shorten the distance from the controller to battery or obtain larger gauge wire. It is also possible to double up the existing gauge wire (i.e. two wire runs) to simulate a larger gauge wire.
Problems with Current
Current Reading: 0 A | Time of Day: Day, clear sunny skies
Possible Cause:
(1) Current is being limited below 1 Amp as per normal operation.
(2) Poor connection between solar array and controller.
How to tell:
(1) The State of Charge (SOC) screen is close to 100% and the Sun and Battery icon are present with an arrow between.
(2) With the solar array in sunlight, check the voltage at the controller solar array terminals with a voltmeter. If there is no reading at the controller solar array terminals, the problem is somewhere in the wiring from the solar array to the controller.
Remedy:
(1) Check all connections from the controller to the array including checking for correct wire polarity. Check that all connections are clean, tight, and secure. Continue with the solutions below for additional help on low current readings.
Current Reading: Less than expected | Time of Day: Day, clear sunny skies
Possible Cause:
(1) Current is being limited below 1 Amp as per normal operation.
(2) Incorrect series/parallel configuration and/or wiring connections and/or wire gauge.
(3) Dirty or shaded module or lack of sun.
(4) Blown diode in solar module when two or more modules are connected in parallel.
How to tell:
(1) Battery State of Charge screen is close to 100% and the Sun and Battery icon are present with an arrow in between.
(2) Check that the modules and batteries are configured correctly and check wiring connections.
(3) Modules look dirty, overhead object is shading modules or it is an overcast day in which a shadow cannot be cast.
Note: Avoid any shading no matter how small. An object as small as a broomstick held across the solar module may cause the power output to be cut to almost nil. Overcast days may also cut the power output of the module to almost nil.
(4) Disconnect one or both array wires from the controller. Take a voltage reading between the positive and negative array wire. A single 12 volt module should have an open circuit voltage between 17 and 22 volts. If you have more than one solar module, you will need to conduct this test between the positive and negative terminals of each module junction box with either the positive or negative wires disconnected from the terminal.
Remedy:
(1) Reconnect in correct configuration. Tighten all connections. Check wire gauge and length of wire run. Refer to Suggested Minimum Wire Gauge.
(2) Clean modules, clear obstruction or wait for conditions to clear.
(3) If the open circuit voltage of a non-connected 12 volt module is lower than the manufacturer’s specifications, the module may be faulty. Check for blown diodes in the solar module junction box, which may be shorting the power output of module.
