How a solar PV and battery storage job comes together

In his latest article for Installer, Mark Allison outlines what’s involved in a solar PV and battery project.

I can’t believe its 2024 already, something that seems ever more obvious as I get older is the speed time actually passes. Happy New Year all the same!

We have an exciting year ahead as we ramp up our renewables work across solar PV, battery storage and EV charge point installations. I thought I would start the year with a run through how a solar PV and battery storage job comes together and the things we learned in 2023. I get a lot of questions around this as others look to enter the renewables space.

They come with unique requirements right from the proposal stage. As covered in last month’s article the maximum demand issue for new equipment such as PV, EV and battery storage is ever trickier. As neighbours add these systems to homes the capacity at a local DNO/Grid level gets ever more difficult. That’s before we even look at heat pumps!

DNO challenges

Thankfully the addition of PV and batteries can help to smooth out some of those issues, but the DNO are on a journey with us on that one!

We are seeing that as we make G99 applications on neighbouring properties, data logging plays an important part in evidencing maximum demand and advising the DNO design teams on the impact our equipment could make.

Point of note with those inverters, don’t forget to check the ENA register for approval. Sometimes equipment is released pre that and can catch you out.

We then have all the challenges around design both in terms of wiring, structure and performance. We use Modecsoft ElectricalOM to ensure our AC and DC designs are accurate with the performance and structural data delivered by Open Solar, Easy PV and engineer calculations. It is really important to ensure you are providing reliable and accurate predictions in terms of performance but also ensuring electrical and structural safety.

ElectricalOM is a fabulous way to produce schematic drawings and handover packs on the AC and DC side of things and helps massively with cable design and certification.

On-site installation

We can then move towards the installation works and these vary so widely from system to system. From the panels which can be roof mounted, in roof, flat roof or ground mounted as examples. Each with unique systems and methods to securely install them in compliance with MCS.

Not forgetting the inverters and batteries some of which will be DC coupled others AC and all with different requirements in terms of isolation and configuration. For example, the GivEnergy All in one battery system comes with a gateway to interconnect all components from the grid, house loads, PV and EV. Where a simple string inverter setup will integrate directly with a consumers existing setup.

Careful attention needs to be paid towards points of isolation in and around all of the equipment both AC and DC. I have shared my views on DC isolation across social media and my YouTube channel. My view is these are essential in the fixed wiring system to allow for safe maintenance of inverters and user operation. While statistics show these and MC4 connectors to be particular failure points we need to look at installation practices rather than the equipment itself. String DC voltages regularly exceed 400V and can be upwards of 1000V on commercial systems. Allowing safe working methods for future electricians should be priority number 1 in any system design.

Safety requirements

We also have the considerations around SPDs, RCDs and earthing which vary product to product especially so when optimisers or micro inverters are utilised. Things can really start to get confusing very quickly. Which is why both accredited training and manufacturer CPD is absolutely essential. Understanding how these systems operate and the requirements on safety can not be emphasised enough. With the requirements of BS7671 on earth rods and earth neutral bond/links in island mode we again need to ensure the equipment has these elements built in or design in suitable systems alongside them.

Once we have reached the commission stage, we get the pleasure of connecting everything to the internet and updating the software. This can often be a frustrating step as the time taken can be several hours. It’s a new element for electricians to consider as usually we design, install, test and turn on more quickly! However, it’s a vital cog in the machine to tick off.

Once we have everything up and running the testing can be completed. Again, with extra bits on top of our usual range of AC tests. We need to ensure the DC system is both safe and performing as expected. We have found the test instrument solutions PV check to be an essential tool on that front. With the ability to factor in current irradiance levels we can determine if the panels are outputting correctly in almost any condition. I say almost as the dark tends to throw a spanner in the works!

Handover process

After the system handover process and customer training we can look at all the paperwork and most importantly collating it. From those original designs and proposals to the final commissioning data. We have to provide manufacturer instructions on every product, serial numbers, G99, MCS, insurance guarantees, electrical installation certificates, building control notifications, solar performance data, cable roof penetrations, mounting system and lots more. The handover packs can become quite weighty documents.

I have to say our general admin processes have improved drastically due to the requirements of MCS filtering into our regular workflow. We use ServiceM8 to collate and manage every single process and document along the way.

We are stepping into some larger commercial systems in the coming months and can’t wait to get stuck in. If you want to learn more about our solar journey and the things we have discovered along the way we have a solar play list on the YouTube channel full of content around just that.

I will cover an install in full on a future article, next month is national apprenticeship week so it makes sense to visit that ever more difficult subject in next months, until then wishing you good health, happiness and every success in 2024!

If anyone would like to suggest topics for future articles, please reach out on social media or via the apprentice 121 website.

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@Mark The Sparky Allison on YouTube