DIY Manual

54 | P a g e 10-543-1 REV A
DIY Manual
Is it overcast outside? Panels need sunlight intensity (photons) to create PV current. No current
= Resting.
PV Input Issue
If the PV input voltage drops too low or is absent, the problem probably lies in the PV source
circuit; that is, the wiring, disconnects, and circuit breaker(s) on the PV side of the charge
controller.
NOTE: A poor connection in the PV source circuit may generate a higher resistance, which leads
to heat build-up, which reduces or “drops” the voltage, which increases the current flow. All of
this is bad! Check your connections.
Reasons for low or no PV voltage:
1. Defective PV module:
a. Bad internal solder joint between cells,
b. Defective internal bypass diodes, or
c. Defective module PV connectors.
2. Defective installation of PV connectors:
a. Poor crimping of the terminal, or
b. PV connector not plugged in all the way.
3. A wire shorting out intermittently:
a. Pinched wire that might be shorting out when the aluminum module frame
expands and contracts, or
b. A wire that has been moving with the wind and rubbed through the insulation.
4. PV input circuit breaker:
a. Loose wire connection into the PV input circuit breaker,
b. Using a circuit breaker NOT rated for DC current,
c. Defective components inside the circuit breaker, or
d. Loose crimp/screw/lug of the wire connected to the circuit breaker.
Low PV Voltage
As explained earlier, the Classic needs the PV Voc input to be at least 133% higher than the
battery voltage to perform MPPT operations. If the Voc is lower than that, the Classic will rest.
How are your panels wired? If all the panels in your array are wired in parallel, the Classic sees
the voltage of a single panel. In a parallel configuration with a 24V or 48V battery bank, more
than likely your Voc is too low and the Classic will rest. Solution – Wire the panels in series, but
not to exceed the Classic’s voltage input limits: 150V for the CL150, 200V for the CL200, and 250V
for the CL250.
Connecting or disconnecting PV
connectors while the module is
in the sun MAY damage the
connector contacts.