Solar Equipment

What difference does the orientation of my panels make?

We can model that for you! We are a company run by data so we can give you very accurate figures of how solar panels facing different directions would perform in the case of your house.

Installing on a slate roof

Most of the time there’ll be no issue or change to setup. In some cases we might use Solar Limpets for slate roofs, and these would come at an additional cost of ~ £300.

How are panels attached to the roof?

To start with, we slide a tile out of the way so that roof hooks can be attached. They’re typically screwed into the rafters or beams of your roof so that the weight of the panels rests on the load bearing beams, rather than the tiles. We then put the tiles back and attach rails to these hooks which the solar panels can then sit on.

Will shading affect my system?

Yes it will. Panels are set up in strings, so if one panel is fully shaded, it will limit the performance of the whole system. We generally use half-cell panels which can manage small amounts of shading by themselves, but still require optimisers or shade protectors in certain situations. In these situations, while optimisers do add a small cost to the installation, there is a large benefit to the system as a whole.

What size panels do you offer?

We offer a range of panel sizes. We typically opt for 390W panels. However there are 410W, even 490W in the market. However these panels are typically brand new to the market and are very expensive per kW. They are also considerably bigger. Hence we find 390W to be the sweet spot for panel size. The only time we'd really recommend increasing this is in cases where roof space is significantly limited.

What kind of panels do you use?

We use monocrystalline, silicon based panels. It’s more efficient (~19% efficiency), than thin film and polycrystalline panels.
They also utilise PERC cell technology (Passivated Emitter and Rear Cell), which basically improves efficiency. But in detail, it improves light capture near the rear surface of the panel and optimises electron capture.
New technology called “dual capture” makes use of two P-N junctions in each solar cell, leading to an improved efficiency of 30%. They’re not large-scale manufactured yet, so they are very expensive.

What brand of panels do you offer?

We offer high quality, monocrystalline panels. These are mostly of the same size and performance. Whilst inverters and batteries have differing technology, we find panels are much the same.

Do you do all black panels?

Yes, we do.

Can I increase the angle of my solar panels above the angle of my roof?

Not really. The reason for this is that if we lift the panels up, it creates a risk of casting a shadow on the other panels, which can have a big impact on performance. This means that we need to space them out more. So a very small increase in performance yields a reduction in the number of panels we can place on the roof. It also makes the panels less secure.

What is the best angle for my solar panels?

Typically the best angle is around 35 degrees. If you'd like we can find out what's the optimal angle for your property, just book a consultation call and one of our Guru's will walk you through it.

Can I get panels on my garden shed?

Typically it is not a good idea. There are two reasons for this:

1. It needs another string on the inverter which increases the cost.This is because each inverter can support two 'strings' of solar panels, and any solar panel in a different environment needs to be on a separate string. So say you have two strings on your main house (over two different roofs perhaps), the shed will then need its own string, which will require another inverter.

2. The roof is not typically structurally sound enough for solar panels. However, it is possible and we could understand the feasibility more on a remote survey.

Why is 20+ panels more expensive?

Related to strings again - you can only have 10ish solar panels on a string. So with 20+ panels, you will need a second inverter.

Is it possible to put solar panels on a flat roof?

Yes, this is possible.
We’d need to set up panels at an angle to optimise solar gain. This will have an additional cost that can increase depending on the size of the system.
Also worth noting is that because we have raised the profile of the panel, the wind exposure will be increased, and so the roof will need to be structurally sound. A structural survey can be arranged if needs be.
Lastly, if the flat roof in question is at the top of the house, and therefore more than 20cm proud of the roofline of the property, you will need to get permission from your local planning authority.
You can read more about the adjustments required for putting solar panels on a flat roof under the title: "Can I put solar panels on a flat roof?" in our Green Guide on how you know whether solar panels are right for you.

Do you do in roof systems?

Yes, we do in roof systems, but you’ll have to book a consultation call to get a quote on this.

Can an Electric Vehicle act as a battery?

Electric Vehicles could act as a battery, in fact most can already but are limited by their software.

The batteries we are discussing today are between 2.5-8 kW. A Tesla is 45kW. So an Electric Vehicle is great for soaking up excess solar, it's like having a big battery outside your house. This provides free fuel.

However, pulling back from the car will have an impact on the degradation of the battery. People are still trying to work out whether the fact that the car battery will last less long offsets the benefit from the improved solar. So our view is that it’s great for free fuel, but probably won't be something you can pull from to power your home.

Our systems are compatible with most EV car chargers. We have performed installations with Zappi car chargers.

How large are the batteries?

About 0.5mx0.5mx0.2m. Larger batteries a bit larger. Smallest a bit smaller. 25kg.

Should I get battery ready?

If you go for a non battery ready inverter, and you change your mind in the future we will have to put in a new inverter which would be an expensive change (~£1,000 for the kit, plus labour ~£450). For around £500 more you can get a battery ready inverter right off the bat. Whilst solar panels have stabilised in price, battery technology is likely to change a lot in the next 5 years, so being battery ready allows you to take advantage of any future developments in battery technology.

Will battery prices come down?

In all likelihood yes, as battery technology is constantly evolving, with the rise of Electric Vehicles and the electrification of the grid.

What type of battery do you use?

We use Lithium-Ion.

Will my battery system power me in a power cut?

No, unfortunately your battery system won't power you in the event of a power cut.

If my usage is always higher than my solar output, why is my battery not always empty?

Yes, by looking at the graph, your usage will exceed solar production, but this is an average over the whole year. In the summer, solar power production will be higher than usage. Also, usage in a common day is spiky, so in the troughs (nobody’s in the house, just the fridge on for instance), your solar energy will be able to charge up those batteries.

How does an inverter work?

An inverter converts the power from your panels into power you can use in your home. The inverter can then connect to a battery, and put excess power into it, or pull from the battery when there is not enough solar. They can also connect to the internet and give you values on how the solar is performing.

How does clipping work and where does the excess power go?

Essentially, when the power output is about to breach the limit of the inverter, the inverter forces the panels to work in a less efficient way and convert more of the sunlight energy into heat energy. Since panels are only ~20% efficient in this conversion process, the resultant increase in temperature of the modules is relatively low.

For example: In a 12 panel system, if all panels are producing at their maximum 365W, the total power is 4380W. To get down to the 3680W that the inverter will allow, the panels would be forced by the inverter to dissipate 700W across them all i.e. 58W each, essentially becoming 15% less efficient in converting light to electricity. This is the "worst case scenario" for a brand new system in the peak period of sunlight. Especially in the UK, the heat created is not a problem and can be easily handled by most modules. In addition, as they increase in temperature, they become less efficient which means that as they get hotter, they produce less electricity and therefore less excess (that would be converted to heat).

How large are the inverters?

The same as batteries, so about 0.5mx0.5mx0.2m. Larger inverters a bit larger. Smallest a bit smaller. 25kg.

How does an EnPhase Inverter work?

Enphase inverters (most expensive option - see model), are microinverters installed on each panel. As such, each panel can be optimised individually without the need for optimisers. However, if one fails, you would need to go up onto the roof to reinstall (scaffold, etc). They do have a longer warranty on them (25 yrs), so failure is not likely.

When an EnPhase inverter is coupled with a battery, an additional inverter will be installed as well. This means that the system is compatible with Agile tariffs. DNO permissions for systems of this sort will take longer, however.

How do agile tariffs work?

Agile tariff optimisation charges up your battery with cheaper wholesale energy at night,  when it’s available, so that you can use it during the day. This is particularly useful in winter when there is less solar to charge your battery.

To benefit you, you will then need to switch to a tariff with different rates. The night rate will be very cheap, the day rate expensive. But this will work for you since during the day you will be using your solar. The easiest way to get one of these tariffs is to get a smart meter.

At the moment there is not much benefit from having an agile tariff, as the night time rates are not particularly discounted owing to rising wholesale costs.

A note on Economy 7 tariffs - these provide fixed rates, one for the day and one for the night. The benefit to these are that, unlike agile tariffs, they are not dependent on wholesale energy prices, and are thus not subject to fluctuation in the market. Unless you are an Economy 7 house, you will need a smart meter to use this tariff.

What size inverter should I get?

We do a lot of maths to work out the inverter size as we are a tech company first. We look at where in the UK you are, slope, angle of roof, batteries etc… So we are very confident our sizing is right. A larger inverter will allow an increased peak performance, but will then be less efficient in lower sun levels. We can increase the inverter size if you'd like, but we would not recommend it.

Also worth noting, if you install an inverter >3.68 kW, you must get approval from the District Network Operator.

What is the breakdown cost of a battery-ready system?

This cost difference from a panels only system comes down purely to needing a hybrid inverter, which are more expensive.

Wi-Fi Connected?

All inverters have Wi-Fi dongles included - also known as a Data Logging Stick.

What's the cost of a replacement inverter?

Inverters may not last the lifetime of the panels so they may need to be replaced. Inverters are unlikely to last the lifetime of the panels, with a working life of roughly 12 years. At 2023 prices, an inverter replacement can cost between £600-£1200 depending on the make, model and type, and would require a qualified electrician to install (not included in cost estimate).

A note on the nature of optimisers

These need power to run, and therefore act as a slight drain on the system. This should be considered before putting them on a system.

String size and the necessity for second inverters

The typical string maximum for panels is 10. Each inverter has two slots for strings, hence a maximum of 20 panels.
Each roof needs it’s own string. There is some flexibility here, however:
• If a roof is the same direction and only 2 or 3 degrees different in pitch, these panels can be placed on the same string.
• If you want to place a single panel on a different roof, but don’t want to add a second inverter, this can be achieved by optimising this single panel, allowing it to be placed on the string for another roof.
• For larger inverters (Solis 8.0kW, for example), the slots can support more than the usual 10 panels.

Where is the equipment made?

It depends on the equipment chosen. The vast majority is made in China, regardless of where the company is based.

Why China? Lowest cost, higher quality. They have the best infrastructure in place, and so produce the most cost effective, robust option.

Do you do in-home displays (IHD) for my output?

Yes we can do. The inverter manufacturers we use come with tracking apps which allow you to monitor a range of performance-related information for your system, including how much electricity you are generating.

What size are the wires you use?

Two wires, each around 5mm in diameter to connect inverter to panels and battery.

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