Precision Solar Alignment Instrument
Maximise solar yield
with geometry.
Enter your location, lock the sun's direction with your compass, and SolMax calculates the exact tilt, panel facing direction, and two-leg stand angles that capture the most sunlight — from first-principles astronomy, right in your browser. Free, no cloud, no data collection.
Smart Solar Geometry
Uses standard solar-position equations (declination, hour angle, incidence) to find your optimal panel angle — no API calls, no cloud dependency.
Live Sun Compass
Point your device at the sun to see its exact position on a compass. Lock the sun direction for optimum panel facing.
Stand Angle Calculator
Get exact angles for the two-leg stand: front leg, back leg, base width, and leg heights — ready for installation.
How it works
How to use SolMax
A step-by-step walkthrough — from location to optimised panel alignment.
Enter your location
SolMax needs your latitude and longitude — these are the only inputs that drive the solar geometry. Your latitude determines how high the sun climbs in your sky throughout the year.
The sun chart shows three curves — winter solstice, equinox, and summer solstice. The higher a curve reaches, the more direct sunlight your panels receive on those days. Once you have a location, the chart becomes specific to your latitude.
Set fitting height
Roof mounting
Panels are installed on your rooftop. Default first-floor height is 11 feet. This is the most common residential setup.
Ground mounting
Panels are installed on a standalone frame on the ground. This gives full freedom of angle and direction, but requires more space and structural support.
Set roof type & panel specs
Roof type
Flat — your roof is almost level. Panels need a tilted stand to angle them toward the sun. Sloped — your roof already has an angle built in, and panels can follow that slope.
Adjustment type
Stationary — panels are fixed to the roof through a stand at a set angle. Movable — panels can be adjusted or re-angled seasonally.
Roof facing compass
Drag the needle or tap a compass letter to set the direction your roof slopes toward. This matters because a south-facing roof (in the northern hemisphere) gets the most total sunlight.
Panel wattage
Enter your panel's nameplate power rating in watts. Typical residential panels range from 350W to 500W. This is used alongside the geometry and weather data to estimate your energy yield.
Use the Sun Compass & Lock Direction
Once your location is set, the Sun Compass appears automatically. Rotate your device and watch two needles track in real time:
- Red needle — the direction you're currently pointing your device (from the built-in compass sensor).
- Yellow needle — the sun's exact position in the sky right now, calculated from your coordinates and the current time.
The locked direction appears on the results compass, showing you exactly which way to orient your panels for maximum energy capture.
Adjust for weather
Solar geometry assumes clear skies, but real weather reduces output. Adjust three sliders to match your site:
- Cloud cover — average percentage. 0% = desert clear, 100% = permanent overcast. The default of 35% approximates a mild climate. Fetch real data with one click.
- Daytime temperature — panels lose efficiency above 25°C. Hot climates see 8–15% power loss on summer afternoons.
- Days since rain — dust and dirt accumulate on dry panels, blocking light. Rain washes them clean. 7 days is a typical default.
Calculate & interpret results
Tap "Calculate optimal alignment" — SolMax runs a two-stage brute-force search across all possible tilts and directions to find the combination that maximizes sunlight capture for your chosen priority.
Understanding the outputs
- Tilt angle — how far the panel leans back from flat. Steeper tilts favour low winter sun; shallower tilts favour high summer sun.
- Direction (azimuth) — the compass direction the panel faces. This matches your locked sun direction for optimum energy capture.
- Effective sun-hours/day — the average daily equivalent of full-intensity, straight-on sunlight after accounting for geometry, weather, and system losses.
- Stand angles — the exact angles for the two-leg stand: front leg (vertical) and back leg (angled to achieve the tilt), plus the base width and leg heights.
Reading the charts
- Sun elevation chart — shows how high the sun gets at every hour for winter solstice, equinox, and summer solstice. The 10° dashed line marks the altitude below which light is too scattered to be useful.
- Bar chart — effective sun-hours per month. The tallest bar shows the best month. The pattern across the year tells you if your array is balanced.
- Month table — exact numbers for each month: productive window, day length, and effective hours.
The science in one page
SolMax uses standard solar-position equations from the solar engineering literature (Duffie & Beckman, 2013). The calculation chain is straightforward:
- Solar declination — where the sun is north/south of the equator on a given day (varies from −23.45° to +23.45° through the year).
- Hour angle & day length — how far east or west the sun is from the local meridian. Sunrise to sunset defines the daylight window.
- Solar altitude & azimuth — the sun's height above the horizon and its compass direction at any moment.
- Angle of incidence — the master equation. It combines latitude, declination, hour angle, panel tilt, and panel azimuth into one number representing how "straight-on" the sunlight hits your panel.
The optimiser evaluates thousands of (tilt, azimuth) combinations across representative days for every month, picks the best one, then refines with finer resolution around the winner. The result is the static tilt and direction that captures the most sunlight for your chosen priority.
Quick reference
Ready to optimise your solar array?
Open the tool →How high the sun climbs above the horizon at different times of year — low curves mean long shadows and shorter productive windows, high curves mean more direct light.
Location
Your latitude determines the sun's height in the sky all year — the single biggest factor in panel angle.
Fitting Height
Where will the panels be installed? This affects wind exposure and structural requirements.
Roof & panels
Tells the instrument what you're mounting to, and your panel specification.
Enter how many panels you'll install and each panel's wattage — this is all we need to estimate your total energy.
Weather & environment
Local conditions affect real-world output. Adjust these to match your site, or fetch typical data (free, no API key).
Which way to face — on the map
The green arrow points the exact direction your panels should face. Switch between satellite and street view.
Hold your phone flat and turn around until the red needle lines up with the green arrow — that's the way to face your panels.
How to build the stand
Your energy production
Hour-by-hour on a typical day
| Time | Sun height | Share of day's power | Approx. energy |
|---|
Strong sun-hours by month
| Month | Sun window | Day length | Strong hrs |
|---|
Important notes
Help SolMax improve — self-learning
Once you have actual production data, let us know how close the estimate was. This helps refine the model for your region.
The Science
Understanding the science behind your solar panel alignment
The problem it solves
Solar panels produce the most energy when sunlight hits them straight-on. SolMax finds the fixed tilt and direction that captures the most sunlight.
How the calculation works
SolMax uses standard solar-position equations. At its core are four key quantities:
The optimization algorithm
SolMax uses a two-stage brute-force search:
- Stage 1 — Coarse sweep of all directions and tilts.
- Stage 2 — Fine refinement around the best candidate.
The result is the static tilt and direction that captures the most sunlight for your chosen priority.
Row spacing
SolMax calculates minimum spacing using the worst-case solar altitude on the winter solstice.
Limitations
- SolMax models geometry only.
- It does not model cloud cover, humidity, dust, or shading.
- Clock times use standard time and your location's astronomical solar noon.
- Treat results as an optimal-aiming guide, not a guarantee.
Data sources
The solar-position algorithms are based on:
- Duffie & Beckman (2013). Solar Engineering of Thermal Processes.
- Cooper (1969). Klein's average-day approximation.
- NOAA Solar Calculator for verification.
No external APIs, no server calls, no data collection.
Contact
Questions, suggestions, or feedback? We'd love to hear from you.
Open source
SolMax is free and open source. Contributions, issues, and feature requests are welcome on GitHub.