I’m Going Green!

I have finally decide to dip my toes into the Solar market. I have decided on a self build, as this gives me much more control over the system, how its installed and future expansion plans (More panels, home batteries, off grid etc)

Starting small with 3 x 400w panels (Trina 400w panels) giving me a max 1.2Kwh output, paired with 3 x Enphase iq7a inverters and an Enphase Envoy S (metered)

So as I bought this, the regulations have changed around “plug in” solar options (In the UK) and now must be wired into their own breaker on the distribution board, dashing my hopes of wiring it straight into the existing ring main. As chance would have it, there was no room left on my existing distribution board, so I took the opportunity to upgrade to an RCBO board.

Now the other challenges:

Mounting location is on a garden cabin, 1st issue is it requires a 45m run of armoured cable to get from the house to the cabin. 2nd issue is the pitch of the roof – only 10degrees, woefully too shallow for the UK! The first issue is relatively easy to sort, the second issue not so much. I originally purchased a Fastensol Hanger bolt mounting system that anchors into the roof beams on the cabin, with 2 aluminium cross beams to mount the panels too. This would give me a decidedly sub-par output and I had to do something.

I looked into some Solar tracking options, but most of these revolve around 2-axis tracking for panels mounted on a pole – these would not work for my flat roof.

I have decided to go full on DIY, with a linear actuator and 2 gas struts for each panel, linked to an ESP32 and a relay board for control.

Ok, so that makes them go up and down, but how do I know how much to move them?

I’m looking at using a MPU-6050 on each panel, wired back to the ESP32. The MPU-6050 is a 3-axis gyro that can be used to report the angle of the panels. It will report in 3 axis, although I am only using one axis for this project.

The next challenge is to wire all of these to one controller, for this I need a “multiplexer” – an in between device that will present all 3 MPU-6050s on different addresses. By default ,the MPU-6050 uses a fixed hardware “address”. For this, I used the cheap TCA9548a Multiplexer, which can handle 8 devices, more than enough for my requirements.

At this point, wiring was becoming an issue, 12v to the actuators, 3.3v to the gyros, and power for the ESP and Multiplexer. At this point, I took a break and spent the weekend learning the basics of Fusion 360 and modelling an enclosure. At this point, I leave you, part 2 to follow soon, with pictures, code and more sweat and tears!

Read Part 2 here

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