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Solar Panel Angle Calculator – SPAC FAQ

What is SPAC ?

SPAC, or Solar Panel Angle Calculator, is a web
application. It was developed by mechanical engineer Miroslav Mimic.
The project started in 2021 as a theoretical calculator for sun ray
angle and sun irradiation. The first version.beta release was in
August 2022,

The next version

    • 1.0. Real-data calculations are added. A new algorithm is


  • 1.1 Switching to MySQL
    Possibility of choosing panels and inverters from the database
  • 1.2 The user interface has been changed. The database has been
    extended. Add the possibility to the annual profit calculation.
  • 1.25 Bugs fixed, database extended


What can I use SPAC for?

SPAC can be used for any kind of solar
investment estimation. SPAC
is primarily intended for prosumers and aspiring prosumers. In other
words, SPAC is intended for anyone who intends to invest in solar

Btw What is prosumer ?

what angle calculations can I use SPAC?

SPAC can be used for fixed-angle applications
(roofs and power plants), one-axis trackers (mechanical or manual),
and two-axis trackers. In all cases, you will get results.

Is SPAC free?

SPAC is free, has been free, and will remain free. It is written in
PHP, JavaScript, and MySQL, and it runs on the Apache2 web server.

What is the current version of SPAC?

The currently released version is 1.25 beta, published on March 27, 2023.

What advantages does SPAC give me over other similar applications?

SPAC is more oriented on angle setup optimizations. Rough
assumptions are kept to a minimum.
SPAC does not
calculate what you need, but the energy you can achieve with the
desired PV module configuration.

makes SPAC innovative?

Unlike classic calculations that approximate the zenith of the sun and Liu
Jordan’s formula, SPAC uses time irradiation for each hour, the
incident angle, and all that depends on the statistical value of
climate factors.

What is Liu Jordan method ?

Is SPAC safe?

SPAC is virus-free and type-safe software.SPAC does not use cookies
or any technology to gather user privacy.

I use SPAC for project design?

Although, with the help of the SPAC application, you can get all the
relevant data from the desired PV module configuration (energy gain,
annual money gain), SPAC is not yet intended for the creation of
ready-made projects.

additional data requires SPAC?

In order
to get the final estimate of the annual profit, you need to know the
price of electricity in USD/kWh.

Is SPAC hard to use?


Only three data points are required for the basic calculation:
latitude, tilt, and orientation to the south.


SPAC is written in PHP and uses a MySQL database for storage. At code, he
uses the maximum amount of object-oriented functionality that PHP can

Miroslav Mitić

Mechanical engineer and programmer for 25 years. Solar energy expert

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