Go Power! GP-PWM-30 User Manual

Page 18

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Solar Controller




© 2012 Carmanah Technologies Corporation

September 2012

Current Reading: Less than expected
Time of Day: Daytime, 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. Check all wiring


(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

(2) Reconnect in correct configuration. Tighten all connections. Check wire gauge and

length of wire run. Refer to Suggested Minimum Wire Gauge in Section 5.

(3) Clean modules, clear obstruction or wait for conditions to clear.
(4) 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.