It is possible to use personal computer or
hand-held devices to control inverters and charge
controllers. You can monitor output data or pro-
gram the equipment remotely.
It is crucial to know the details of the workings
of an inverter or charge controller. Also, under-
standing the safety and system-performance conse-
quences of altering the operational mode is vital. It
is recommended that only qualified professionals
make physical adjustments to inverters and charge
controllers.
Remind customers that repairs are costly. Indi-
cate that any adjustments to the equipment can void
the warranty and result in repair and service costs.
In the case of some customers, use clear fingernail
polish to cover the enclosure screws or bolts to keep
them out, or indicate that they are trespassing.
Normally, the default programming set at
installation for inverters and charge controllers
does not need to be changed, but do not count on
it. Never assume anything!
Maintenance Tools and Equipment
PV systems use many tools and equipment during installation. Sometimes PV
systems need advanced testing and analysis. This may necessitate special equip-
ment such as IV tracers, resistance testers for insulation and grounding, long-
term operational data logs from hand-held devices or personal computers, or
power analyzers that calculate harmonics, voltage sags and surges, and in-rush
currents.
These items should be serviced and maintained regularly:
Basic hand and power tools
Multimeters
Ladders
Personal protective equipment (PPE)
Electrical test instruments
Solar shade measuring devices
Pyranometers
Pyroheliometers
Hydrometers
Thermometers
IV tracers
Resistance testers for insulation and grounding
This 260 kW PV-powered commercial inverter has
multiple doors and panels for maintenance and
component replacement, thereby making rebuilding
an inverter an alternative to buying a new one while
extending the inverter life.
Courtesy of PV Powered
CHAPTER 10 Quality Control, Testing, Troubleshooting, Monitoring 245
Long-term operational data logs from hand-held devices or
personal computers
Power analyzers that calculate harmonics, voltage sags and surges, and
in-rush currents
Use RMS hand-held digital multimeters when testing PV systems and com-
ponents. Make sure the multimeters can measure more than 600V AC and DC.
Multimeters have many features that are very useful to PV system maintenance,
including minimum/maximum recording, average recording, and a hold func-
tion. RMS hand-held digital multimeters also can test individual modules and
source circuits for short-circuit voltages.
Use clamp-on ammeters to measure voltages at test points. Good quality AC
clamp-on ammeters can be very expensive. They are also very popular. DC clamp-
on ammeters use Hall effect sensors. They can measure currents from
milliamps –1000 A.
Use an irradiance meter, such as a pyroheliometer or pyranometer, to mea-
sure the intensity of sunlight. Pyroheliometers measure direct irradiance.
Pyranometers measure total global solar irradiance. Pyranometers are easily
transportable. They can immediately measure solar irradiation during system
checkout or maintenance. They also can be incorporated into PV systems to
record long-term solar irradiation. Prices of pyranometers range from reasonable
to very expensive. Unfortunately, the accuracy of the device increases with its cost.
Irradiance measurements help to compare information for PV modules and
arrays. Some of the information collected includes current and voltages. This
information is compared at two instances. It also is compared with a shared set of
circumstances. The measurements are converted into standard rating conditions
for product comparisons.
Use a hydrometer to test the electrolyte within a flooded lead-acid battery.
The hydrometer checks the specific gravity of the electrolyte. There are two types
of hydrometers—Archimedes and refractive index.
The Archimedes hydrometer uses buoyancy from a sample of electrolyte.
The electrolyte is pulled into a float chamber to determine the specific gravity.
The specific gravity is calculated from adjusted markings on the float chamber.
Adjust the readings if the electrolyte is significantly warmer or cooler than room
temperature.
The refractive index hydrometer uses a prism and light refraction to deter-
mine specific gravity. Using a small amount of electrolyte, the prism will refract
light at bigger angles when electrolytes have higher specific gravities.
Use a non-contact IR thermometer or an IR camera for PV system installa-
tion and maintenance checks. The IR devices measure array and module tem-
peratures. They also measure electrical equipment, connection, and terminal
246 ADVANCED PHOTOVOLTAIC INSTALLATIONS
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