Solar Power. A Mini Adventure.

[Sundayjumper]

I’ve been solar-curious for a while. The idea of free electricity is a winner but the cost of entry is still quite high for a proper system and the payback time can easily be 10-20 years which just feels too long.

I’d previously read about micro inverters and balcony systems (small DIY installs that sit on a balcony or flat roof and literally plug straight into an existing wall socket). Last week I was in the garden and looking at the garage wall I realised that would be a good spot. It’s about 7m long and faces almost perfectly south. And we’ve got an outside socket there. Hang some panels & plug it in. I don’t fancy climbing up on the roof to install stuff but down at ground level it’s easy. If I could get deals on s/h stuff and install it myself it would bring the payback time right down.

So I started trawling eBay & Facebook marketplace. I got eight LG 300W panels @ £25 each. They’re 1.67m x 1m and will fill the wall nicely arranged landscape as a 4x2 grid. Micro inverters are clever but get pricey with multiple panels so I went with a single grid-tied string inverter from eBay for £76. Some very basic wall brackets - £20. Other general hardware and cable I already have in stock. And the garage consumer unit is just on the other side of the wall so I can connect into that. I’m basically £300 in.

I lashed it together yesterday, panels propped up against the wall and lying on the ground as the wall brackets aren’t here yet and it seems to work It was peaking close to 1.5kW and my smart meter telling me I was giving the electricity company 700W for free !

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Now it’s obviously not going to churn out 1.5kW constantly. I need to fit it all together properly and monitor it for a few weeks. Which finally brings me to a question. The inverter is no longer supported by the manufacturer. The data logging was done via their website, not conveniently hosted on the inverter itself. Bugger. Has anyone here got experience of *cheap* data logging ? I can see some devices on Amazon that have an app but it’s not clear if you can extract the raw data. Ideally I’d like .csv files I can import into Excel or Power BI.

[Sundayjumper]

Amazon e.g.:

https://amzn.eu/d/fLEi9Gm

[Jobbo]

If you're putting power back into the grid, you'll need to notify the DNO - for your level of generation I think that would be after connecting but I'm not an expert. Here's some guidance:
https://mcscertified.com/notifying-dnos/

ETA: and notify your house insurance, obvs

[Sundayjumper]

So very definitively untriggered that you brought it into an unrelated thread

[Jobbo]

I'm enjoying the fact I touched a nerve. Call me Jobbroccers.

Genuinely, it could be a serious issue if you didn't tell your house insurer - even my professionally installed solar system needed to be notified.

[Sundayjumper]

On the bright side, you got the last word.

Anyway, original question, anyone here have any experience of data logging power consumption ?

[Sundayjumper]

Long article about security:

https://cybersecurity.bureauveritas.com ... rabilities

Including some detail about the connectivity of these kits being shared across many manufacturers, and a github link for a data logger !

https://github.com/Woutrrr/Omnik-Data-Logger

But I'm not enough of a geek to understand how to do it

I have a Synology NAS running 24/7, if that could run the data logging that would be ace ! (and free)

[tim]

Is your inverter an Omnik model Steve?

[Sundayjumper]

It’s not, it’s a Hosola, but as that article points out the same gubbins are used by a whole range of brands:

…a large range of PV inverter vendors such as Omnik, Hosola, Ginlong, Kstar, Seasun, SolaX, Samil, Sofar, Trannergy, GoodWe, Power-One and others. That's interesting because it means whatever vulnerabilities we discover affecting the Omnik kits apply to multiple different vendors.

And the web interface is absolutely identical to the screenshots in the article.

[tim]

See if you can get it to talk to this - worth a go. https://www.omnikportal.net/

It's the one i use for my system

[Sundayjumper]

Oh, cool, I'll check that out !

[Sundayjumper]

Bloody hell. It works. I think I probably owe you a drink for that !!

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[tim]

Ha, good job!

[integrale_evo]

This is the sort of solar install I would consider. I still don’t really get how it works.

Your install was making 1500w, but you were only pulling 800 and feeding the rest back to the grid? When you say for free I assume because you don’t have a feed in tariff, so overall you only pay for whatever you pull from the grid? So makes sense to use as much of your free solar when it’s producing and minimise energy consumption at other times.

Is it really as simple as wiring in the panels and plugging in the box?

Do you need the data logging or is it just for your own personal information and to keep an eye on how much you’re making / using and I guess ultimately find out the payback point and after that how much you’re saving?

[Sundayjumper]

Your install was making 1500w, but you were only pulling 800 and feeding the rest back to the grid? When you say for free I assume because you don’t have a feed in tariff, so overall you only pay for whatever you pull from the grid? So makes sense to use as much of your free solar when it’s producing and minimise energy consumption at other times.

That was a brief spike, as an illustration, but yeah. I don't think feed-in tariffs are really a thing any more, not like the fairly generous ones that some early adopters got, so it's just a reduction in what I draw from the grid, not an income-generating scheme. I basically wanted it to cover the power needed to run the pump (90W) & heater (650W) for the paddling pool. A big array with a big surplus during the day is when you want a battery. Then use the battery to run the house when the sun goes down. I'm at a disadvantage with the panels on a wall rather than high up & angled. But I've also only invested just over £300 so I don't mind experimenting a bit

Is it really as simple as wiring in the panels and plugging in the box?

Minimal "see if it works", yes, but I'm going to wire it properly. Isolators both sides (DC in & AC out) and then into an RCD on the garage consumer unit. I'm not entirely sure how the inverter works. When it fires up it runs a check on the house AC side to determine exact frequency & voltage and synchronises itself. It then regulates its AC output to a very slightly higher voltage than the grid so that it pushes power in that direction. There's some fairly clever real time control going on.

Do you need the data logging or is it just for your own personal information and to keep an eye on how much you’re making / using and I guess ultimately find out the payback point and after that how much you’re saving?

Yes - just geeky curiosity. Whether it covers running the pool, and trying to estimate the breakeven point.

[Jobbo]

In principle your plan to use it to harvest electricity to run the pool sounds exactly right - the times when the generation is highest are the times when you most want to use that power. I had that in mind with our solar panels but didn't bother putting the pool up this year

I do get 15p/kWh for export, and overnight pay only 7p/kWh, so I set the battery to charge overnight and export all the solar which isn't being used during the day. Not the way these setups are intended to work, I'd imagine, but if Octopus incentivise you with a tariff that encourages exporting rather than charging your battery, that's what'll happen.

[Mito Man]

I expanded my woodland off grid solar at the end of last year. Now have 2x 300w panels and a cheap Chinese 2kwh black Friday lithium battery that I would in no way trust in an indoors environment. It produced enough electricity in winter to run a router and a small dehumidifier in a metal shed which runs a few hours each evening. Works perfect.
I'm not confident enough to start messing with fuseboards, and I imagine you need a proper electrician and certificates for all that but I can see something like the above being decent for a garden shed/outbuildings.

[Sundayjumper]

<wellthatescalatedquicklymeme>

I now have a 3.6kW inverter / 4.2kWh battery combo. Aston for scale. That’s just the cover in the pic but it shows how much wall space I need to clear in the garage

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[DeskJockey]

I for one am shocked that you couldn't stop yourself from messing more with it. It is sort of your style!

[Sundayjumper]

I for one am shocked...

It's very much my aim NOT to be shocked during this project !