Inverter and solar PV hardware/software

[reg...@gmail.com]

Is anyone in this forum experienced with solar PV hardware and especially software? We're hoping to install a typical home roof 14-panel PV array, and the panels themselves seem pretty robust and standard.

I was slightly startled when it was pointed out the rather random inverter manufacturers have fairly familiar instruction manuals - for hacker components and cheap instruments. These don't seem to be "blue chip" white goods, at least their documentation is basic. Furthermore, they all seem to have 'cloud connection' and remote monitoring apps.

Is anyone concerned about longevity of inverter and battery storage control hardware/software that seems to be of unknown provenance? Could these be bricked via firmware update? Any security concerns, given home data will be shared with an overseas server in a totally unknown company?

I'm not especially paranoid and am aware using gmail/WhatsApp on my android phone is fairly loose with data, Alphabet and Meta own me already. I also appreciate if we don't make this stuff locally it's going to have to be shipped from somewhere with factories.

But my phone handset isn't directing several kW to and from my home.

And more importantly, to be worthwhile, solar PV installations should have 20-year lifespans. If my android phone handset is bricked, it's not such a big deal.

Maybe the inverter software/firmware isn't a big deal- and is more replacable than the rest of the installation?

Thoughts, wisdom, experience welcome? It's hard enough trying to find a reputable installer with any time/capacity.

Adding in trying to select trustworthy hardware as well, is putting off what should be a worthwhile installation.

Al

[Alex Gibson]

Hi Al,

 

My experience is a little out of date but currently researching a third install having recently moved house.

 

My first 2 were on the same roof at my old house and were 2 near identical rows of 7 BP solar panels, with 2 SMA Sunny Boy inverters, each with a separate FIT generation meter and install ID, done a few months apart.

 

I’m too out of date to advise on current market but having got halfway through the rated 25-year lifetime of my first install, I would say I believe the kit was built to last.  The panels had decreased in yearly average output less than 2%, below any reasonable threshold for seasonal variance.  An early incidence of bird guano from an old aerial I had removed had greater impact.  They were still >5% above original quoted output.

The Sunny Boy inverters made exactly the same slight electrical humming noise under full sun as on day 1.  Their LCD screens still worked, and had a nice choice – to eliminate fallible switches, you had to knock on the panel to activate the LCD.  I would buy those again.

 

I would not be put off finding hackable components inside an inverter – for example some Nest security products are being discontinued, their cloud services turned off and those aspects of the devices effectively ‘bricked’ – But – as they use the Zigbee protocol they are still able to minimally work as sensors, so could be repurposed into Home Assistant.

 

I am just getting into Home Assistant, so for me an inverter that I can potentially talk to via its non-proprietary protocols and hook into a thriving open source ecosystem without voiding the warranty would be great! 

 

As for made in China… well almost everything is, with varying levels of directness and quality control.  I was glad of my German made solar gear as an early adopter, but now China is well up to speed, I would now not hesitate to go for a Chinese brand if I can find out enough about it – ideally a teardown.

 

Who will actually do the install for you?  Your warranty would be from them and I would be more concerned with the backing and longevity of the company issuing the guarantee than the kit. 

 

We had to have roofing work done and found some of the bad hacks one of the solar installers did to fix up tiles broken during our install – they saved replacing the tiles by using mastic – which worked for several years but cost us a lot more to do right than it would have cost them to replace – so while the scaffolding is still up, check or even pay someone to have a look, and ask the installers – there should be no shame in them cracking a couple of decades-old roof tiles, this should be something they are ready to deal with and fix properly.

 

Don’t let any actual or potential issues put you off – it is a wonderful feeling to look back at your house and know it’s generating power, saving and earning you money and helping get carbon emissions down right now.

 

Cheers,

 

Alex Gibson

 

edumaker limited

 

+44 7813 810 765    @alexgibson3d  

 

Unit 3B Bacchus House, Calleva Park, Aldermaston, READING RG7 8EN

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[Frank in Woodcote]

Yep, exactly what Alex said. Good info.

I used to work in the PV field a while ago. If you want to look at a typical setup and how it all works, drop by. Easier to discuss all the bits when you have something in front of you... Send me a PM.

I've split my system into two inverters, but still the same set of panels (to stay on my tariff).

There are some 'reasonable' battery storage systems out there, but I still think the cost per kWh depreciated over their life-time is still way too high IMHO. They last 10 years max (with minimum guaranteed performance)- just like an EV battery. The solar immersion heater controllers are well worth having if you don't have a heat pump, as they save gas heating costs.

There's a technical-price investigation on PV battery storage by EEV blog on YT that might be of interest.

-frank 👍🏻

[David Price]

Hi Al,

We've had PV installed for 5.5 years now - a 5kW array of 18x 280W panels with microinverters feeding a SolarEdge inverter (3.8kW o/p) and an immersion diverter. Basically I filled the south-ish facing roof well above the invert output to cover a wider range of light level to give more daylight capture per day and days in the year generating around 5 MWh per year. I've used an EV for 4 years so even more of the surplus is used charging that. We have been on the lowest FITS generation/export tariffs and originally the payback was estimated at 12 years, however with the immersion diverter, EV, and recent hike in energy costs the system finished payback this summer.

From April to September our electricity draw from the grid has dropped from around 350 kWh per month (2016) to 100 kWh even with the EV. We use gas for heating and hot water and our average daily gas usage has dropped to roughly half for may - august, this includes occasionally forcing the gas boiler to heat the hot water to keep pump and valves in good working order.

We switched cooking and washers to daytime, appliances to battery powered where possible and of course the EV to maximise solar usage but have no house battery yet as I don't think they are cheap enough yet for their short lifetimes. The EV is a different case as the value of a car depreciates anyway but the EV runs at very low cost especially with PV charging and can provide a 240v/16A mains supply (on-board inverter) for necessary appliances in the event of a power failure. This reduces the justification for a house battery and bridge even more.

We have a standard variable rate tariff with Octopus and I am considering switching to agile and/or moving from FITS export to their Fixed Outgoing SEG.

The problem for solar in the UK is heating. I generate at least 100 kWh per month so and my next experiment is to get some electric heaters and see how they exploit PV and support our lifestyle in the cold months and whether a house battery then becomes a more effective investment.

The system monitoring involves cloud based storage and apps but I've had no issues todate, while all control is local. The only thing I don't have is a way to track actual energy export but that's down to having disparate components and no applicable industry standards.

If you have a roof I recommend filling it with panels, get an EV and above all have the panels pigeon proofed as once the bastards roost there they multiply like crazy, the noise and unbelievable quantities of guano will drive you nuts and it can take months to shift them.

david

[Malcolm Napier]

Having followed David's experience over the last few years, we have just taken the plunge.

We have 13 x Canadian Solar CS6R-405MS panels (5.25 kWp) on a virtually south facing roof with a low slope (around 15 degrees), pigeon proofing (David's experience was mirrored by that of one of my daughters), a FoxESS F5000 inverter and a Solar iBoost immersion diverter. It should have been 14 panels but our foul pipe vent got in the way of the 14th panel.

My main reason for posting is in reponse to Alex' search for an inverter. I came to the challenge in the opposite direction. Finding an installer that was able to do the work using reasonably rated componentry (rated in the sense of customer reviews) at a price that I regarded as value for money was the challenge. Having (eventually) achieved that, I then found myself with an inverter and cloud based service that made little or no sense in terms of the information that it provided. But help is apparently at hand (for Fox Solar/FoxESS owners at least) in the form of I AM Eccles on YouTube, a community on Facebook (which I am not prepapred to join) and a forum. It appears that Home Assistant plus the advice offered by these resources (which I think all emanate from the same person) offer a way forward based on Home Assistant. Hopefully the same support will be around for different inverters via different communities.

My approach was to have panels with an insurance backed guarantee - since that is the bulk of the cost (once the cost of scaffolding, etc. for the installation of the panels has been taken into account). The inverter and diverter (iBoost) are components that can be accessed and replaced much more easily and could be expected to be replaced in the lifetime of the installation - particularly if Alex' experience is shared more widely and the panels remain useful beyond the 25 year period. 

I contemplated a battery - as the optional price quoted seemed more attractive than I was expecting. But on further enquiry, I was told that they are in very short supply and linking the purchase of the panels to the supply of a battery would introduce significant delay. As with the inverter and diverter, I was told that they are easily replaced (or in my case could be added afterwards).

My plan is to get to grips with what we can do with our system as installed with reasonable behaviour modifications and then look at the Octopus flexible tariff (as used by Robert Llewellyn) and whether that makes batteries a reasonable investment.

[David Price]

Notes:

1. An initial install carries VAT of 5% but I believe adding anything later carries full VAT

2. Get your roof surveyed and the trusses reinforced as necessary.

david

[Bob Dunlop]

Hello,

Well we've had 16 panels (4kW) on our roof for over eleven years now.
I would say "just runs" but actually the PV string input failed on our
original invertor at about fours years. No quibble warrantee
replacement with a newer model as they no longer had units from the
original manufacturer. Reset the clock on the warrantee as well which
I thought was good.

Both units had network connections at my insistance as this was before
the "cloud" and I wanted to monitor the performance myself. I did have
to open a port in my firewall on one occasion to allow the manufacturer
to push a firmware upgrade, but closed it again after.

First box supplied stats via JSON with absolutely no documentation at
all but not to hard to hack. The second only admitted to a web page
but again after a little playing wget and sed would churn out the
numbers I wanted.

System paid us back in 7 year and that without factoring in the 30%
reduction in the electricity bill at the time. Panel output is down
about 8% now but the invertor replacement gave us a couple of percent
boost.

On Wed, Dec 07 at 09:08, reg...@gmail.com wrote:
> Is anyone in this forum experienced with solar PV hardware and especially
> software? We're hoping to install a typical home roof 14-panel PV array,
> and the panels themselves seem pretty robust and standard.

--
Bob Dunlop

[Frank in Woodcote]

Good info on here!

After you've had the PV a few years, you only do the occasional system checks as the gear is pretty reliable (if correctly installed). In the beginning, you check a few times a day, then once a day, then once a week... Always run underated and it becomes even more efficient; like a 6kW inverter for a 4kW array, that kind of thing. You'll notice within 24h if something is wrong. In nearly 14 years, not a single problem. Panels still belting out the same power they used to. And it is really difficult to test if they are running at the same efficiency without a lab test setup as the sunlight is very variable. You need to check incidence angle, lux and panel temperature. Every year is different. Our payback was 7 1/2 years.

To avoid the pigeon (and mice/rats) problems, tray-mounting systems are the way to go. Lighter too, so you don't need to modify your roof at all. And you'll end up with a stack of spare tiles for future roof repairs. None of those ugly rails that allow creatures and leaves to get behind.

[Frank in Woodcote]

I have a full working design (CE tested) for a basic solar immersion heater controller divertor thing (hardware, software and pcb layout), for free, if anyone wants a copy to build themselves. About £30 in regular components.

[najey...@gmail.com]

Solar professional here. The concerns you've highlighted do come up more often than you'd think! The main one being that when an inverter manufacturer goes under, its monitoring software is usually rendered useless; the exception being if the monitoring is handled by a third party. Concerns of privacy aren't such a big issue as most inverters are pretty basic and can't really be remotely switched on and off (which doesn't stop people from phoning up claiming that they have (Yes, David the landscaper from Farnham, the Chinese Government has nothing better to do than switch off YOUR PV system))! A lot of inverters have APIs which allow you to export and process data such as total generation, spontaneous power output, and (in some more advanced inverters) shading and panel health. 

If you'd like to go down the path of independent energy monitoring (assuming you're not including your gen meter in all of this), some kind of CT monitoring is the way to do it. Neurio is a fairly easy brand to work with, but there are some others. Let me know if you want a comprehensive list. Just be aware that most of these would include or be limited to some kind of online functionality.

@David Price:

As part of the governments energy independence incentives, they've removed all VAT on any domestic PV installations. Almost every PV company (Spirit included) gets struccy done as a form of legal ass-covering.

Sorry if this is brief, as I'm just doing it in a break as my own two pennies and haven't had a chance to read the whole thread. If you want I'm happy to answer any specific queries you may have, just ask them in the form of a clear and concise question :) 

[Malcolm Napier]

I have just looked at my invoice (15/11/2022). It says "VAT 0%"

I wish that I had known about Frank's "solar immersion heater controller divertor". I would have forgone the commercial one and built one of his.

[Stuart Ward]

The only thing I would add to Alex answers would be to add a open energy monitor to the mix. 

Stuart

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