Inverter Monitor
My Story
In July 2021, I changed my petrol car for an electric one. Not surprisingly, this resulted in an increase in my electric bill, and a dramatic reduction in my petrol costs. Whilst I had always accepted that making my own petrol was not advisable, it seemed that making my own electricity was perfectly possible, and the most common way was with solar panels.
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In the UK (where I live), there is a Microgeneration Certification Scheme (known as MCS). Not all installers belong to the scheme, but if solar equipment is installed by a member of the scheme it is much easier to get paid for any surplus electricity. There are other advantages for the customer, such as someone else to complain to should things go badly wrong.
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MCS has a website, which lists all the scheme members and is searchable by area, so early in 2022, this is where I started my search. I contacted some local installers by email with my requirements, and eventually placed an order for a GivEnergy based system.
Welcome GivEnergy
Like any true geek, I love to have the latest stuff, and accept that products at the "leading edge" are still in development and likely to have flaws. A Unique Selling Point of the GivEnergy offering is the advanced Cloud Portal. Checking this out before ordering revealed that it needs a login which is only available once you have the equipment. However a Demo Portal is available with impressive made up numbers that add up perfectly, beautifully displayed on charts and graphs. There is also a mobile phone app, but downloading it just takes you to a login screen for the portal.
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After some supply chain issues and a catalogue of errors, the installation was completed in October 2022. Armed with Portal login credentials, my expectations of flaws were quickly confirmed. Real world figures don't add up precisely (I never really expected them too), but measurement inaccuracies up to 20% adrift from the true value, means that the Portal can only be used as a guide. My model is now called the Gen1, and within a year has been superseded by the Gen2 and the Gen3; a clear sign of a company improving it's products and offerings.
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Then came the mobile app. Bear in mind, I am talking about when I first saw this app, and not improved versions that have been released since. This app managed to combine the portal inaccuracies with illegibly small graphs, a clumsy interface, poor reliability, bizarre permissions requirements, and used different terminology to the portal.
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I have written a few apps before for Android mobile phones, and thought it wouldn't be difficult to write a better one ...
Enter Kotlin
In fact, a few days was all it took to make a basic app to collect figures from my inverter and display them on a screen. Once I had the basics working, I abandoned the app and started again! I had started writing the program the old way, which is slow and would take ages to develop into a full blown masterpiece.
In "olden times" (before about 2018) most mobile apps were written using the Java programming language, developed in 1995 by Sun to sell their big business computers (the kind of computers that utility companies use to send you bills). Nowadays, Kotlin is the new programming language of choice, and this was an exciting opportunity to learn a new skill.
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Starting from scratch, the app quickly developed into a useable form, and in March 2023 I decided to share my work on the Google Play Store. One downside of choosing Kotlin, is that the programs only run on Android 5 and above, but despite this it quickly gained over 100 downloads.
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There is no team behind this app, just one person who does a bit of programming every now and again when it's cold and wet outside. I hope you like the app and thank you for your support and the reviews on the Play Store.
