Monitoring is very common with Solar PV systems. Often residential monitoring consists of a device that measures current and voltage on the ac output of the inverter and relays that information via the Internet.
Monitoring for larger systems often has more parameters that are measured, such as wind speed and irradiance. Some monitoring is on the source circuit level and other monitoring would be on the inverter output level. When diagnosing a problem on a PV system, make sure to stay safe.
This means looking at your system first, turning things off with disconnects and then taking measurements and saving the corrections for last when you know what is wrong. Always remember to be safe! Making sure that your voltmeter works before testing with it is standard practice.
Performance issues of Solar PV and troubleshooting
PV system turns off on hot sunny days.
- Problem is voltage gets too low when temperature gets too hot.
- Correction is putting more modules in series to raise voltage or getting another inverter with a lower voltage input window.
Ground fault detected.
- Likely a fault on a source circuit.
- Measure voltages on separate strings to find ground fault.
- Make sure everything has been turned off first.
- Be careful of getting shocked.
Blown fuse in a combiner.
- Likely positive to negative fault.
- Multiple strings feeding backwards through one fuse in a combiner.
- Carefully correct the problem after visually determining what is wrongand turning everything off.
- Find the fault and correct the problem being careful to not get shocked.
Performance is not good for a few days in the winter according to monitoring.
- Look for snow or bad weather.
- Solution is to wait or move snow.
In a dry climate performance is worse at the middle or end of the dry season.
- Look for soiling (dirt).
- Solution is to wash modules.
- Check for low operating voltage problems due to heat on array.
- Check for excessive voltage due to undersized conductors.
Battery maintenance in Solar PV
Check voltage with volt meter.
Clean terminals and equipment.
Check connections.
Inspect fuses and disconnects.
Inspect ventilation system.
Battery maintenance for flooded lead acid batteries that are not sealed:
Check fluid levels.
Replace missing fluid with distilled water.
Check specific gravity of battery acid.
- Hydrometer checks battery acid with a density test
- Refractometer checks battery acid with a test to see how light bends in fluid.
Equalization charge is a controlled overcharge for maintenance of non sealed flooded lead acid batteries. Equalization charge splits H20 and releases bubbles of hydrogen and oxygen, which will stir up the battery.
