PVsyst.
If you work in solar engineering, you will see this name in every feasibility study, every lender technical report, every serious tender document.
It is not optional software. It is the industry standard.
The problem: the first time you open PVsyst, the interface is genuinely intimidating. Meteonorm databases, MPPT voltage windows, loss fraction diagrams — it is a lot. But the core workflow is logical, and once you understand the sequence, the rest follows naturally.
Here are the eight steps to complete your first solar simulation in PVsyst.
1 Download and Install PVsyst
Go to pvsyst.com and download the latest version. The software runs on Windows only.
PVsyst offers a 30-day free trial with full functionality. This is more than enough time to complete several complete project simulations and learn the tool properly.
After the trial, a one-year licence costs around €600 for a single user. For students, educational licences are available at a significantly reduced rate. Contact PVsyst directly with proof of enrolment.
Use the trial period deliberately. Open the documentation, watch the official PVsyst YouTube tutorials, and build at least two complete projects during those 30 days. You will learn more in one month of hands-on use than in a semester of passive study.
2 Create a New Project and Choose the System Type
Launch PVsyst. On the main screen, click Project Design.
PVsyst offers four main system types:
- Grid Connected — the most common type for utility, commercial, and residential solar tied to the national grid
- Stand Alone — off-grid systems with batteries and a charge controller; no grid connection
- Pumping — solar-powered water pumping systems with a variable-speed pump
- DC Grid — direct current distribution, less common
For your first simulation, choose Stand Alone (off-grid). The logic is slightly simpler than grid-connected because you are optimising for the worst production month rather than annual yield.
Give your project a clear name (e.g., "Residential_OffGrid_Algiers_4kWp") and save it. PVsyst creates a project folder where all your files will be stored.
3 Set Your Site Location and Meteorological Data
This step defines the solar resource available at your site. It is one of the most important inputs in the entire simulation.
Click the location icon in the project setup screen. You can search by city name or enter coordinates manually.
Best practice: open Google Maps in a separate window, navigate to your exact site, and copy the GPS coordinates from the URL (format: latitude, longitude). Paste these directly into PVsyst. This ensures you are using site-specific data, not a nearby city's approximation.
For Algeria, PVsyst's built-in Meteonorm database is reliable and free to use within the software. It includes irradiation, temperature, and wind speed data averaged over multiple years. For bankable studies (financing, insurance), you may later be required to use SolarGIS or NASA SSE data instead — but for learning and initial feasibility, Meteonorm is excellent.
After setting coordinates, click Import Meteonorm. PVsyst will retrieve the monthly irradiation and temperature profile for your location. Review the Global Horizontal Irradiance (GHI) values — for most of northern Algeria, annual GHI should be in the range of 1 700–2 100 kWh/m²/year. Southern Algeria can exceed 2 500 kWh/m²/year.
4 Define Panel Orientation (Tilt and Azimuth)
PVsyst will ask for two orientation parameters: tilt angle (inclination from horizontal) and azimuth (compass direction the panels face).
Azimuth convention in PVsyst: 0° = true south (for the northern hemisphere). This is the opposite of standard compass bearings and catches many beginners. South-facing panels in Algeria = azimuth 0° in PVsyst.
Tilt angle for off-grid systems: PVsyst can optimise this automatically, and for stand-alone systems it optimises for the worst production month (typically December or January in Algeria). Accept the software's suggestion as a starting point — you can adjust it manually later to account for site constraints like roof angle or wind load.
Latitude: ~36.7° N (Algiers region)
PVsyst optimal tilt for off-grid: approximately 40–45°
Azimuth: 0° (true south)
→ In practice, rooftop constraints often mean 20–30° tilt; account for the output reduction in your panel sizing
5 Enter Your Energy Needs (User Needs)
This screen is where you enter your appliance list. PVsyst calls this section "User Needs" or "Energy Needs".
Click Add Load for each appliance. Enter the appliance name, power in Watts, and hours of use per day.
For the refrigerator, do not enter the rated power multiplied by 24 hours — a refrigerator compressor cycles on and off, running roughly 8–12 hours out of 24. Check the appliance energy label for actual daily kWh consumption, or estimate: 50–60% of rated power × 24h for older models, 30–40% for modern A+++ models.
PVsyst also asks for hourly distribution: during which hours of the day does each load run? Morning loads, evening loads, continuous loads. This matters for battery sizing — a system with heavy evening loads (after the sun goes down) needs more battery capacity than one that runs loads during daylight hours.
Be realistic about timing. The most common mistake at this stage is setting all loads as "continuous" (24h). This vastly overstates battery requirements. Spend five minutes thinking about when each device actually runs — morning kettle, evening TV, overnight refrigerator, daytime fan — and set the hourly profile accordingly.
6 Configure the Battery Bank
PVsyst's battery sizing screen asks for the desired loss of load probability — the percentage of time the system is allowed to fail to meet demand. For a primary residence, 0–5% is the standard specification. For a secondary home or irrigation pump, 5–10% may be acceptable.
Enter the number of autonomy days (days of battery storage without any solar input). For northern Algeria with occasional winter cloud cover, 2–3 days is standard.
PVsyst will calculate the required battery capacity and suggest a battery voltage (typically 24V or 48V for systems above 1 kWp).
Lead-acid vs LiFePO4 in PVsyst. PVsyst defaults to 80% depth of discharge for lead-acid. In real installations, limit lead-acid discharge to 50% to extend cycle life (400–500 cycles at 80% DoD vs 1 200+ cycles at 50% DoD). Manually override the DoD parameter to 50% for lead-acid, or use the LiFePO4 model which natively supports 80% DoD with its superior cycle performance.
7 Select Solar Modules and Charge Controller
Modules
Click PV Modules to open the component database. PVsyst contains specifications for thousands of modules from all major manufacturers.
Search by manufacturer or model. If your specific panel is not in the database, you can create a custom module by entering data from the manufacturer's datasheet: Pmax, Voc, Vmp, Isc, Imp, and temperature coefficients.
PVsyst will determine how many modules are needed and suggest a string configuration (number of modules in series per string × number of strings in parallel).
Charge Controller / Regulator
For stand-alone systems, select the charge controller type: PWM or MPPT. MPPT is recommended for any system where the string voltage significantly exceeds the battery voltage — which is most practical systems.
Three critical checks when selecting an MPPT controller:
- Maximum input voltage: must be greater than the array Voc at the coldest expected temperature (cold increases Voc). In northern Algeria, minimum temperature is rarely below 0°C, but in the Atlas mountains it can reach −10°C.
- MPPT voltage window: the range within which the controller operates at maximum efficiency. Your string's Vmp must fall inside this window.
- Maximum charge current: must exceed the current calculated by array Wp ÷ battery voltage × 1.25.
8 Run the Simulation and Interpret the Report
Save your project. Click Run Simulation.
PVsyst processes the monthly solar resource data against your system configuration and generates a comprehensive results report. Here is what to focus on when reading it for the first time:
- Loss of Load Fraction (Floss): the percentage of demand that was not met. Target: below 5% for a primary residence. If this is too high, increase panel power or battery capacity.
- Monthly energy balance chart: shows production vs consumption month by month. The deficit months (typically December–January for Algeria) tell you whether your winter sizing is adequate.
- System losses breakdown: a Sankey diagram showing where energy is lost — temperature, wiring, battery, MPPT inefficiency. This is invaluable for identifying where a design can be improved.
- Battery state of charge: PVsyst plots the daily minimum battery charge across the year. If the battery regularly reaches 0%, your autonomy is insufficient.
A simulation result is only as good as the inputs. If your load profile is wrong or your location coordinates are inaccurate, the output will be misleading. Garbage in, garbage out — this applies to every simulation tool, not just PVsyst.
For Grid-Connected Projects
The workflow for grid-connected systems follows the same sequence, but without the battery sizing step. Instead, you define an inverter (rather than a charge controller + batteries), and PVsyst optimises for maximum annual energy yield rather than minimum winter deficit. The key output metric shifts from loss-of-load to Performance Ratio (PR) and Specific Yield (kWh/kWp/year).
Performance Ratio (PR): 75–82% is typical for a well-designed system
Specific Yield: 1 600–2 200 kWh/kWp/year depending on location and tilt
If your simulation gives a PR below 70%, check your loss factors — especially temperature, soiling, and shading losses
Want us to review your PVsyst project?
Our engineers review your simulation file, identify errors before you commit to procurement, and walk you through the results in a live session.
In Summary
PVsyst is not difficult. It is precise — and that precision is exactly what a solar project needs.
Follow these eight steps, set your lead-acid batteries to 50% DoD, always verify the MPPT voltage window against your string configuration, and read the loss-of-load fraction before you sign off on any design.
Your first complete simulation will take a few hours. Your fifth will take twenty minutes. And when a client or investor asks "what does the simulation show?" you will have a professional, bankable answer.
If you want an experienced engineer to sit with you and work through a real project — your data, your site, your numbers — that is exactly what Diresk's technical sessions are designed for.