Solar photo-voltaic systems do not only consist of solar modules and inverters. It is true that 60% to 80% of the total system cost is the cost of solar modules, however choosing the right balance of system equipment is an important part of the design.
It can take couple of minutes to get a quote for solar panel and inverter pricing and to decide on a brand. However, it can take more than couple of hours to figure out how to install the modules on the roof, selecting the correct racking system, attachments, flashings, and sizing the cables etc. If you need any assistance in your design, please fill out this form.
In the below table, I wanted to show the must-have's of a solar PV system.
Equipment Decision Factors
Solar panels Roof dimensions, price, availability, project size (consumption)
Inverter System sizing, availability
Racking and Mounting Mounting preference (roof, ground, tilted, flush, standoff etc.), local fire code, Flashing, Roof type (shingle, tile, flat, composite etc.) Grounding wires, clips, lugsSystem size, racking type, local code
Combiner, junction box Inverter specification, installer
DC and AC Disconnects Inverter specification, local code
Breakers and switches AC and DC disconnects, wire size, current flowing on wire
Wire size and type Distance, ambient conditions (humidity, solar radiation etc.), voltage and current, voltage drop calculations
Module connectors Module type (MC4, Radox, Tyco, MC3, Amphenol etc..)
Lighting arrestor Local code, local weather
Monitoring Owner preferredSignage (Warning Signs), Local code Metering Local code (Check with the utility company)
Off-Grid Systems
Battery Bank System voltage, energy consumption, number of days of autonomy, application (wet, agm, gel)
Charge controller Battery voltage, PV system voltage and current
Battery cables Distance to charge controller and inverter
Battery monitoring Battery type, charge controller brand
Comments
I know there isn't a typical solar PV system, but can anyone give me rule of thumb to help with estimtes? Of the cost of equipment in a solar installation, what percentage does the balance-of-system (BOS) cost? (When I say BOS I mean balance of the panels) Thanks for the help on this.
Good questions. I am sure this answer will be challenged as it can vary greatly but of the cost of equipment, the panels will run around 55-65% of the cost while the inverter should be roughly 10-20%. The racking can have a very wide range based on the application but it should run around 5-15% of the equipment cost and the electrical equipment and additional balance-of-system equipment wil be roughly 3-8%. The size of your system and application will make these rough estimates vary widely but this should give you a rule of thumb. I hope this helps.
Solar Systems are really good as they help us generate electricity from solar energy. The installation of PV cell is really an interesting one. Thanks for the interesting procedure.