#1 Oct. 15, 2016 14:50:40

SteveRogers
Registered: 2011-12-08
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Raspberry Pi & SBFspot for data logging and transfering to pvoutput.org (SMA inverter)

I've been using pvoutput for several years and uploading data at 5 minute intervals using PvBeanCounter software on my Windows PC. You can see my outputs here - http://www.pvoutput.org/intraday.jsp?sid=12290 . This arrangement was not ideal as I do not have my PC (an ageing Dell tower system) on 24/7 and there was often a problem in bringing the website up to date after a holiday when the PC was powered down for weeks.

So, I decided to investigate using a Raspberry Pi computer for the purpose as this has low consumption and can be left on full time. A quick estimate put the electricity used at around 15-20 kWh per year, assuming the Pi is not used for other purposes and so is in idle mode most of the time.

I bought a Raspberry Pi 3 starter kit (computer, 16Gb microSD, case, cables) plus a heatsink and an hdmi to vga converter (so I could use an old monitor; you can use your television) for a total cost of £62. I loaded Raspbian as OS from the NOOBS distribution provided on the microSD card), got the Pi connected to my LAN and wifi and then downloaded SBFspot software from https://sbfspot.codeplex.com/ . The documentation provided on this site is excellent and holds your hand through the whole process of compiling, installing and setting up a script to automatically log data every 5 minutes (during daylight hours only) and transfer it to pvoutput.org.

Some unix experience might be helpful (I hadn't used unix for over 6 years) in using the file editor to set up the configuration, but probably not essential. It probably took me around 3 hours.

After getting everything running I shutdown the Pi, removed the keyboard, mouse and monitor and relocated it next to my inverter in the loft before powering up again. Interestingly, I note that the data logged includes inverter temperature and AC voltage as an extra.

The Pi 3 is overkill for the purpose but it comes with integrated wifi and Bluetooth unlike earlier versions and saves on hardware cost as a result. Currently, I don't log consumption (other than meter readings) or export data but I guess this could be done in a similar way if the hardware is suitable e.g. ecoeye

I don't know if similar free software is available for non-SMA inverters.

I did have an initial, abortive attempt to use a different logging system (Google code called sma-bluetooth / smatool) but this had errors whilst compiling the program and the documentation is poor. I'm happy with SBFspot so far.

I guess the scripts in SBFspot could be hacked to provide a method for uploading detailed data to Microgen. I am not clear if Sheffield would routinely need/use such detailed data e.g. for modelling purposes.

Steve
URN 215

Edited SteveRogers (Oct. 17, 2016 15:12:49)

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#2 Oct. 20, 2016 08:16:30

SunnySouthwell
Registered: 2014-01-22
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Raspberry Pi & SBFspot for data logging and transfering to pvoutput.org (SMA inverter)

Thanks for the detailed posting Steve, I'm a bit tempted to follow your lead. At the moment I upload daily data by hand as and when I feel like it, automating it would be a much better way, see http://www.pvoutput.org/list.jsp?id=10474

Steve
URN 6390

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#3 Nov. 1, 2016 11:55:51

martint123
Registered: 2013-01-09
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Raspberry Pi & SBFspot for data logging and transfering to pvoutput.org (SMA inverter)

I'm currently using one of the earlier £80 HP Microservers to get data to pvoutput. Definitely overkill but it isn't too bad for consumption and is also running other stuff like my PVR system, security camera (at present keeping an eye on the loft mounted boiler pressure gauge!) and big dumping ground as a NAS. I use a EoN supplied thingie for consumption measuring and I think I would miss that.

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