Installing panels on a garden room.

Radders said:

We have a South facing flat roofed garage approx 10mtr x 4mtr. In Yorkshire Anyone able to give a laymans opinion on best way forward. We also have an EV

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LOL... my brain can't process "a South facing flat roof". If it's flat it's not facing south or east or west or north . Guess you mean one of the sides is south-facing? If so, which one?

The good news for you is that since Dec 2023, installation of PV on a flat roof comes under 'permitted development', provided that you are not the curtilage of a listed build or within a conservation area. You will need to check that the roof structure will support the weight of panels, taking into account wind down-force, uplift and snow-loads.

The permitted development allows the panels to extend to a max of 600mm above the highest point of the roof, excluding any chimneys. This limitation will suggest that a 'landscape' rather than 'portrait' configuration would be best, to achieve the highest tilt, without exceeding the height restrictions - alternatively you could apply for planning permission outside of the permitted development rights.

Going back to your south facing roof - is the 10m or 4m side to the South? Either way you will need to work out the max number of rows of panels you can achieve at any given tilt, without causing shading on the panels that are not at the south-facing edge. If it's the 10m side on the south, then I suspect you will achieve two rows of panels at around 15 - 20 degrees, but I haven't done the maths.

If you have 10.5m, rather than just 10m width, then you may be able to get 6 common size (1.7m x 1.1m) panels per row - if not then 5 panels, giving a total of 10 to 12 panels.

EV convert said:

However, home owners have to consider the potential consequences of not following the guidelines - would house insurance become invalid in the case of a fire (not even one involving the battery)? Would you be able to rent out or even sell a house with a non-compliant battery installation (look at the problems 'rent a roof' solar installations have created)?

And would registered installers even fit batteries in non-compliant locations as their registration status could potentially be compromised?

Alternatively, if you have to build an enclosure or fit a fire rated window and/or door, the cost will increase dramatically and it becomes a financial non-starter.

For all those reasons I believe PAS 63100:2024 does ban a large proportion of the housing stock from having battery storage installed.

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I suspect that this PAS is the first step towards the much stricter rules and regulations that we see in other countries (like USA NEC Code compliance, UL listed equipment and inspections for sign-off). So far, IMHO, we've been lucky in the UK to not have too many restrictions in the solar field.

I don't believe that house insurance would be legally permitted to decline a claim for not meeting an advisory recommendation, but I can see that non-compliance is best avoided wherever possible. And it makes sense that reputable installers will go beyond their legal responsibilities to deliver safe solutions.

My 2p worth, having spend quite a bit of time going through PAS 63100:2024, is that it is far off becoming a legally-binding standard. Ignoring the fact that is only addresses fire risks, it fails to distinguish between different battery chemistries. I suspect this is why there are the restrictive recommendations (such as 6.5.4) for ventilation ports and those ports being > 1m away from doors, windows and other ventilation ports.

Neither does it address any detail regarding type of overprotection devices. For example, there have several cases reported of fires caused by the limited arc fault protection afforded by the fuses used, whereas (IMHO), those fires may have been avoided with the correct use of Class-T, NH or BS88 type fuses.

EV convert said:

Never mind installing indoors, Under PAS 63100:2024 even positioning batteries outdoors is banned within 1m of a door or window - even if there are two or more exits! So if you have a terrace house then forget about installing a battery.

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What's their take on car charging? My car has 60 kWh battery, double what I have as house batteries and it gets charged within a metre of two windows and an exit door. What about people (like Rolfe) they have an integral garage and the charger is in the garage?

Johnb80. I don't know but I have considered that myself - and for exactly the same reason!

In the response from BSI, it did add that the standard was up for review every 2 years so perhaps we won't have to wait too long before getting some answers (or common sense??).

Must go now I've got to plug the car in (literally).

johnb80 said:

What's their take on car charging?

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Not within scope. – PAS 63100:2024 addresses "Fire safety in the installation of small-scale electrical energy storage systems (EESSs) in domestic dwellings that utilize stationary secondary batteries as the medium for energy storage" only.

EV convert said:

In the response from BSI, it did add that the standard was up for review every 2 years

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Minor, but significant point is that a PAS is not a 'standard. In fact, it specifically states "This PAS is not to be regarded as a British Standard".

johnb80 said:

Good choice, you can then get usage like this:-

View attachment 33500

This is typical of how my system runs, some nights we have much higher consumption if we charge both cars and run the washing machine and tumble drier.

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Its been 4 weeks since my 8kWh house battery was installed. No problems so far (touch wood) and not expecting any.

Following a review of the conversations regarding Tomato Energy, I have just signed up to Lifestyle Tarrif switching on 20th Feb. Switching from Octopus Go but Leaving my Gas with them.
My Watts signed on and waiting to go.

UPDATE 24TH Feb
Switching did not occur as planned. Emailed them and received the following reply. Looks like Facebook is showing lots of us in this situation.

"Good Morning,
Thank you for reaching out to us and we truly do apologise for the inconvenience and delay in getting back to you.
We regret to inform you that we have been unable to complete your transfer at this time. This is due to ongoing issues with our switching servers and MPAS system.
Due to this, we have been unable to register this.
Once the switching servers are running, we will attempt to switch this supply over to us. We are currently in the process of getting this issue fixed, this has been logged and once this has been resolved we will then register this site accordingly. Our teams are actively working on combatting this.
We sincerely apologise for any inconvenience this has caused and greatly appreciate your patience and cooperation."

Grandadgeorgec said:

Its been 4 weeks since my 8kWH house battery was installed. No problems so far (touch wood) and not expecting any.

Following a review of the conversations regarding Tomato Energy, I have just signed up to Lifestyle Tarrif switching on 20th Feb. Switching from Octopus Go but Leaving my Gas with them.
My Watts signed on and waiting to go.

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Im sure you will make a good saving using Tomato Energy for your electricity supply. This morning I ran the figures through a spreadsheet comparing Tomato Lifestyle EV and Intelligent Octopus GO. In the 5 months since I transferred I have saved over £280, average over £56 per month saving. Tomato don't have the marketing gimmicks like referral fees, cinema tickets, free coffee etc, they just have rock bottom pricing which I feel is much better.

Since November, I've saved £354 against Eon Next tariff 12 months ago, that's an average of £118. Although that's not an apples to apples comparison as I have gotten rid of gas heating and cooking, which was horrendously inefficient.

I'm a professional in the field of renewable energy. PV modules (panels) are at an all-time low cost, you can get e.g. 540W half-cell mono for ~£55inc. (~48+VAT) they tend to be larger than older panels, efficiency of 21.5% not uncommon. 670W is available, but these are bigger, 233x 115cm
You are MUCH better mounting them on a south/SE/SW pitched roof, because the sun is not straight up in UK. (That would be the tropics!) As Everest said, on a flat roof, you'd have to put them landscape orientation, and have them slightly sloping, He's correct about the 20cm limit, but with permitted development you can exceed this, and put them at a sensible angle, like 30-40deg. Higher the better, they'll get more sun. I spoke to an experienced installer friend, and he says "The solar police aren't around anymore!" so as long as your installation isn't taking the mick, it's highly unlikely to be noticed by the local council.

[ Moderator: "all-time low" → "all-time low cost" ]