My new system has now been commissioned

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Bob Smith

Well-known member
Joined
Jul 13, 2022
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Dear all,

First of all, please let me wish you all a merry Christmas and an excellent festive end-of-year celebration. I would also like to express my sincere thank you to all of you (too many to thank them all) who have been patiently answering my questions for over 18 months.
I came to this website around Summer 2022 because I started to lose faith in the installers I met. I had a clear idea of what I wanted to achieve and many of them tried to convince me it was a bad idea, (see my original diagrams attached). I had done some evaluations of my needs and set clear requirements in terms of storage charge/discharge, wanting to keep my FiT yet use my existing PV array from 2016 to load new batteries along side the new PV.
It has been a long and exhausting journey. I started to contact installers in April 2022 and thought it would be straightforward.
I will not name any companies or people because I understand they have their objectives and interests first and no damage was made apart of wasting my precious time. I do not like their attitude but this could be the topic for another post. This said one company REST were honest upfront and told me that they would not achieve my requirements with the material they sell. I even paid 25% deposit to a company whom I thought understood my requirements but after 6 months of arguments, they ended up saying they could not meet them and gave me my money back (I did have to ring HIES though). At that point, I thought why? why is my project so difficult yet forums like this one helped me to understand it was not my requirements which was the problem but my project was not the typical one either.
Furthermore, as time went, prices dropped and I ended up meeting a company that has been excellent from the beginning til the end and now I have an even better system that I would have had, had that other company convinced me they were right.

So what did I get?

My requirements first:

  • Make the best of the 3 surface areas (small roof, wall and flat roof to produce as much electricity as possible.
  • Use of batteries (2x 5kWh with a provision to reach between 20 to 40kWh).
  • Use both set of panels (existing and new) to charge the batteries. The choice between AC and DC coupled batteries will need to be technically justified.
  • Charge and discharge of the batteries minimum 7kW
  • Preserve the FiT. ie the generation of the 16 existing panels must continue to receive the full FiT as per the 2016 FiT agreement.
  • Continue with the use of the PowerDiverter which heats the water when there is an excess of electricity generated.
  • Possibility to charge the batteries from the grid as and when required either manually or following a programmed sequence.
  • Priorities management: The system must be flexible and user friendly in order to set the priorities between the batteries charging, the hot water and EV charging in the future.
  • Complete monitoring of the system free of charge for the life time of the installation.
  • Possibility to sell the excess of electricity (This will depend on the DNO’s requirements and constraints).
  • The equipments must have at least 10 years warranties.
  • The batteries must be capable of sustaining the house’s electricity needs and this includes the electric underfloor heating.
  • <10 years Return On Investment.

Because of the 12 months struggle with so called professionals/expert and what I have been learning along the way, I decided to get even more technical and design it myself. I have found good documentation and a breakthrough was to learn about Victron ESS. It has exactly the "box" I wanted. The box, as I called it, was to get the new panels, the DC coupled batteries and an AC input from my existing system. I tried to get Victron and Fogstar batteries.
I contacted 4 installers of Victron brands and despite compromises on the panels (they only offered smaller panels) or the batteries, I never received any quotes from any of them despite promises. This was last August and September. I ended up throwing a bottle at the sea on a social media platform and 3 companies were interested. 1 never heard back, 1 send me a quote that did not fit the bill and trying convenience me SolarEdge was the best ever thing that could exist (yet his design did not meet all my requirements) and a 3rd one who first responded to me. "This looks like a fun project".
That last company spent time to understand my requirements, agreed it made sense, however he was not keen on Victron because he never installed it but suggested a brand I never heard of which provided the same functionality than the Victron. The company took care of the applications and never asked for any money even for the G99 application and only a week before the installation only asked for 500GBP. The rest after commissioning. During that time, I was still looking for my large N-Type panels since I had the space. The company has been very patient because until the last minute, the brand changed (mainly because I could find what I wanted but then there was no availability in the UK.) until I discovered AIKO

PS: Due to the 10 000 limitation I had to split the post into two.
 

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You are now wondering what I got.
I got:
16 x 610W AIKO panels (they exist in All Black but not available in the UK, shame unless I ordered a full container)
2 X 450W AIKO (those are all black because they were available and cheaper than the white one)
8 Tigo optimizers (for the panels on the wall and the small roof because they are exposed to shading)
Lux Power Tek 12k Hybrid inverter I thought at some point going with the 7K (the 8 and 10 are not available in the UK) because it was enough to charge and discharge at 7kW and has a AC input. However, I went for the 12 and I'll explain why it is better.
4 x 9.4kWh HanchuESS I originally estimated I'll start with 10 to 12kWh but one battery can only charge discharge at 5kW, so had to go with 2, but then the 7kW hybrid inverter would have charged them at 7kW and not 10). At the last minute I negociated a deal for 2 more batteries.

The company has also been very good with me because I originally wanted to have the inverter and the batteries in the attic. Each battery is 72kg and they were OK with that. However, I learnt that the 12k Inverter can be noisy and the company measured the sound level for me. I then decided to build a soundproof booth in my attic. However, I could not get it wrong, then I realized I could get a shed made of proper bricks in my garden for the same price. The company waited for me to have it done (as well as a 21m trench in my garden for all the cables. I am an expert in trenching now lol).

Installation took place on the 6th December, coincidently the day I got my smartmeter (now waiting to be on an export tariff but got on Agile on the 17th of December).

My impression so far,
The 6kWp array facing North West do generate under the worst condition (end of December and very cloud, so they will definitively live up to my expectation unlike many comments made that it does not make sense to have panels facing North.
The wall panels facing South West, as expected, in Winter when the sun is low do generate!!. I have 3kWp and one afternoon reached 2kW (only for 1h or so because the clouds came back again).
The batteries. I can charge and discharge them at 12kW. This is 3kW each so 3/5 of their maximum capacity which is an added advantage when the temperature are cold (by cold I mean 0°C). With a 12kW charge I can really make a difference with the 30min slots of Agile. In total I can charge my 37.4kWh in 3 hours. That's only 6 slots. As you can imagine, I never drain my batteries so it takes less than 3 hours. In addition, with the bad weather, I have already ran 48hrs with the batteries alone (before being on agile). This said, I did not buy 4 just for my own usage. I intend to export too. so I'll keep 50% for the House in Winter (and surely 25% or even less in summer) and the rest will be for the export (once I have on my export tariff).

The system uses correctly my 2016 array to charge the battery or the house.

G99. I have been authorized 8kW. Which is OK. This means that if I want to discharge the batteries, the system still has 4kW available for the House.

This is how I started with

View attachment 16457

Then learning about Victron ESS, I wanted this

View attachment 16458

As mentioned above, it has been impossible to get any quotes from Victron, so I ended up getting this ( I removed the Lower Roof NW )

View attachment 16459


The Lux app is OK, It does provide good metrics. eg the input of my Fit Array (showing 655W, and the 3 strings (2 strings for the Main North West roof PV2 and PV3) and PV1 the string with my 5 panels on the wall and the 3 on the lower roof SE. This string also has Tigo and I can get more granularity if I want (there is an integration of Tigo into Lux but it does not give as much info as the Tigo website). (ignore the red battery and the notice, one battery was not fully set up at the time of the screenshot).

View attachment 16460


Another screenshot from the mobile app (PV1, PV2 and PV3 are put together)
View attachment 16461


The inverter provides me also with a lot of information from the batteries such as temperature and cell temperature, cell voltage and battery voltage etc.. In total when I export the data I have an excel file with over 130 columns (I have not yet figured out what they are all for. Yep there isn't much documentation !!!)

The Lux app can be easily programmed but only allow 3 times for charging and 3 times to discharge, I would have like to have more. Maybe one day. Maybe one day I try to become good enough with Home Assistant. I am only at the beginning of my new journey :)

Warranty:
Lux 12 years
Tigo 25 years (but their internet relay only 5 years...)
Panels 30 years performance warranty and 15 product
Hanchu Batteries (the distributor and Hanchu provide a special warranty for the UK. (Unlimited cycles, 12 years warranty min 70% SoC).
2 years workmanship and support

Bonus:
View attachment 16463

As you can see the additional panels despite not being oriented to the premium location (already taken by my 2016 array) allows me during this very grey days) to double my production.

Maybe one day I publish data about the import/export.

I had promised you all some feedback once my system is installed. I could explain all the rubbish talks I had with installers but this post is already quite long and I believe you are more interested in the end results than the journey :)

Once again, thank you very much all (and especially @binky and @johnb2713 ),
I hope too that during that time I have also been able to help others from what I have learned.

Happy to answer questions if you have any :)

Merry Christmas and Happy new year.
 
Hi Bob,
Sounds like you've achieved your goal after many hours of frustration, well done. It will be interesting to hear how it performs over time, please do keep us updated.

J
 
My observations so far:

The North West facing panels have generated 27% of my total generation so far (Total includes my 4kWp from 2016 array facing SE, the new string with panels on the wall (facing West) and 3 on a lower roof facing SE and of course the 6kWp facing NW on the main roof). I did not expect them to generate as much at that period of the year. As we all know the sun is very low, does not really set west but more WSW, and the number of hours of light is very low. I consequently now have high expectation for this NW facing arrays.


The batteries:
As mentioned, I added 2 more at the last minutes (also because I did not know the VAT will be removed for battery alone but managed to get 30% off).
I have 4 batteries 9.4kWh and a charge and discharge of 12kW (export to grid is limited to 8kW though).
This is more power than my original requirements I was aiming for 7kW. I am on Agile since 17th of December and Oye Boy, I don't regret the 12kW of charge. This means that I need 6 slots of 30min to fully charge the batteries. However, they are never empty. so I can really ping point the cheapest slots and charge my battery in no time and with a full battery I can go 48 hours off grid (ignoring the PV generation for now, weather has been cloudy, cloudy and cloudier). For instance, Monday night was the last night with negative prices, I charged the batteries and charged them again last night only (I actually force discharged a bit to ensure I could be paid even more :) )

I know the system ended up being more expensive (This said, it was the same price as a quote I accepted in December 2022 but with fewer panels, only 11kWh of storage and 7kW charge/discharge.)

Finally, my installer has been a real pleasure to work with. All in all, all my frustration has gone and my perseverance paid off.

I will be posting regular updates if you guys want to. Not sure what you are most interested in. The panel's generation? How much I save/earn with importing and exporting?
 
We should have met 18 months ago! I've just about completed what sounds like a similiar journey, I won't name names either but I contacted 6 x companies, 2 x quoted it, one was nothing like what I asked for and the one I bought it off turned out to be beyond a nightmare and completly incompetent. I have just agreed to cut ties with them and I am now sorting the commissioning and DNO signoff having done the entire AC + DC electrical design and installation myself already. In fact all the Solar Company actually did was get a subcontract roofing company to fit the panels, which was a debacle in itself. Then they attempted to overbill me... It went downhill after that.

I went for 2 x Huawei Inverter (6k/3.68k) 2 x Luna Battery 10kwh Each 25 x REC 370W All Black panels split across the roof E/S/W.

I will put a full post together with the whole system design at some point. I would be very interested to compare your generation with my setup. I am based in Southern Scotland.
 
We should have met 18 months ago! I've just about completed what sounds like a similiar journey, I won't name names either but I contacted 6 x companies, 2 x quoted it, one was nothing like what I asked for and the one I bought it off turned out to be beyond a nightmare and completly incompetent. I have just agreed to cut ties with them and I am now sorting the commissioning and DNO signoff having done the entire AC + DC electrical design and installation myself already. In fact all the Solar Company actually did was get a subcontract roofing company to fit the panels, which was a debacle in itself. Then they attempted to overbill me... It went downhill after that.

I went for 2 x Huawei Inverter (6k/3.68k) 2 x Luna Battery 10kwh Each 25 x REC 370W All Black panels split across the roof E/S/W.

I will put a full post together with the whole system design at some point. I would be very interested to compare your generation with my setup. I am based in Southern Scotland.
Yes we should have met. However, I see you joined the forum in summer 2023. I was a lot less active at that period having sorted pretty much everything at that point and finalizing the details with the installers. I see that I have been luckier with my installer. Real pro, patient, competent, there has been absolutely 0 surprise and now I paid it all, I am still in touch with him to resolve teething problems.

I would be more than happy to recommend them but he only covers 1h around Preston.

Yes. we can compare our systems even if we won't be comparing apples with apples.

Feel free to start DM me.
I am also curious about your "Onshape user" :)
 
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