My experience - 2.6kW solar panels I can move home with

Obukit
Obukit Posts: 670 Forumite
edited 20 February 2019 at 1:12AM in Green & ethical MoneySaving
Hi all,

I hope it is okay to share my experience - I couldn't find similar online so cobbled things together. Hopefully it may save someone some searching.

I've wanted solar panels for a long time, both from the money saving and eco friendly point of view. But I've always been stuck with the fact the payback is over years, and they last for thirty years. So unless you are sure you aren't going to move soon, it's difficult to make the investment.

However, with the FIT tariff being axed (boo! :mad: ) there is a lot of good kit around for very little money - so I had to take the plunge. However, I wanted to design it so it could be dismantled and put in the back of a removal van within an hour. And of course it had to be cheap. :money:

There is perhaps the opportunity to get in before the government launches a scheme where you can shop around for the best price for the solar energy you export to the grid.

I'm not an expert but to be honest it isn't a difficult task to do if you have basic DIY and electrical skills. You only really need normal tools, a power drill and something to cut aluminium - I used an electric tile cutter because I already had one but an angle grinder or a junior hack saw and patience would work fine.

Where to mount
The key question before you start. Solar panels are big - 2m x 1m - you don't realise how big until you are next to them. They require a lot of space. The options are.

Ground mount - the easiest because there's no messing around on the roof and no worrying about weights. You also get the most production because you can vary the tilt each season. However, few people have the 4m x 3m area you would need to mount eight solar panels.

Flat roof - a good option if you have one in terms of space vs easiness. The things you need to think about are weight bearing - four solar panels + frames will weigh over 100kg and you don't want them falling through - and also spacings. If you angle the panels at 10degrees (less than ideal) you will need to leave 68cm between each panel so they don't shade each other. If you increase the angle to make them more efficient you need to leave more space. So you can see you need to not only have room for the panels, but also to space the panels.

Sloping roof - the usual option for a reason, it's already at the right angle and you're not using the space. However, to mount the panels you have to drill through the roof into the rafters below which meant it wasn't an option for me. Also, I am very clumsy, and breaking a leg isn't money saving. However, if you are braver than me it is probably the preferable option.

So when you've decided where to put the panels, you need to buy the panels. I spent about £2.2k on everything. What I bought was

Solar panel kit - these seem to come in two types - "plug in solar" kits aimed at DIYers, which come with instructions and more hand holding. You can also get essentially trade kits - from what I could see these were about £1,000 cheaper and you get better quality components.

However, the trade kit comes with no hand holding, just a pallet delivered to your door.

One of the big things that swayed me is that most of the DIY kits seem to come with mini inverters attached to every panel, converting the DC to AC in situ. My experience of putting any electronics on the roof is it's a bad idea, and much preferred the idea of one inverter inside. I ended up going for this kit here although other similar ones are available.

https://www.ebay.co.uk/itm/Complete-Solar-Panel-System-8-x-JA-Solar-325W-Poly-Black-2-6kWh-TRADE-PRICES-/323671128616

The kit comes with the solar panels and also the inverter, clamps for the panels, an isolation switch, MC4 connectors, wiring, and lots of scary stickers to put on your fuse box.

Frames and clamps for the panels - the same seller supplied these for me for £180. I was sceptical at first - after all, it's a chunk of money - but I was pleased in the end. The solar panels have narrow frames, and catch the wind. The frames and clamps are heavy duty, aluminium (so light and not corroding) and secure the panels well. Worth the money for piece of mind.

Overall frame - for this I used a ladder for three reasons. Firstly, it is cheaper than any other frame. Secondly, it collapses so fits in with my aim to have it portable. Thirdly, they already have a rated weight so you can be sure it will hold your panels. You need to have one as long as your groups of panels are. I wanted two groups of four so got 4 x four metre ladders. The ones I got were from Vonhaus at £60 each - they've since put up the price but it is easy to compare.

Energy monitors - you will need to be able to monitor the energy your panels are producing, and the energy currently coming into your charging meter, so you use as much of your electricity as possible.

The cheapest proper meter is called an Eco Eye but it is also really, really ugly. So if you can do without the data recording I bought two Geo Minims - £80 total - which look a bit nicer.

ifqxi1.jpg

Self drilling roof screws - make fixing the frames to the ladder easy.

Ballast and attachments to hold down the frame - panels catch the wind and you don't want them blowing away. I got a load of dense concrete blocks from Wickes @ £1.65 each plus some wire rope & wire rope clamps.

Wooden planks - if you're putting onto a flat roof to spread the load across the joists.

Conduit - to tidy everything up.

Step one - mount the inverter
Yes you want to get onto the roof but it makes sense to mount the inverter first, so you can think about where to run the wires. My advice if you have a kitchen with an external wall is enter the wires there, that way you can run them under the kitchen cabinets rather than mess around with conduit.

Once you have identified a place to mount the inverter you just need to connect the AC side though the isolation switch (supplied with kit) into the meter (supplied with kit) and then connect it to anything on your sockets ring main. Despite the size of the inverter, the maximum it will kick out on a <3kw kit is 13amps, so it's not an issue.

I've removed the conduit here to make it a bit easier to see.

33ncl86.jpg

Unless you are connecting it into your bathroom (stupid idea) this is not Part P notifiable.

Step two - mount the frames
Pretty simple here - screw the frames to the ladder. If you are using a three section ladder, as I was, you need to mount them so they all align. With a hammer drill and 8mm socket you can screw them directly in without needing to drill first, which makes things quick.

Personally for the bottom section I removed the bottom section of the supplied frame, cut out sections for the ladder rungs, and put the frame so that it straddled the ladder frame. This makes no sense to explain but it's clearer if you try. Probably more secure, probably overkill, but might as well make use of/ruin the blade of the tile saw.

Step three - position the ladders
In the UK the ideal angle is about 45 degrees - see the ridiculously detailed Solar Panel Tilt website - but as above if you have limited space on a flat roof you may want a less ideal tilt in return for more space.

This will be specific to your setup - suffice to say the frames will apply both horizonal and vertical force and you need to use planks and supports as appropriate so the roof can bear the weight and the panels don't slip.

Step four - mount the panels
If you've paid extra for the frames and clamps then this is a fairly easy job (especially if you have a second person) - just position the panels, put the clamps in and tighten with a 5mm allen key.

10zs9xx.jpg

If you're opting to mount them yourself - good luck.

Step five - connect the panels
There are two broad options here - series or parallel. I won't bore you with the details as there isn't much difference except to say.

Most trade inverters require a minimum of 70V so you will probably have to wire them with at least two in series.

If you have them at different angles/locations you should wire those groups in separate paralel circuits, because if they are in series a poorer performing group will affect the better performing one.

If they are all in the same location it is easier if they are all in series.

Each group of panels can be daisy chained together - the connectors between each one will only fit one way. That means the only MC4 connectors you will need to fit are ones at the inverter itself, and any connections you make from the solar wire to your panels.

MC4 connectors are easy to fit - don't believe the nonsense about needing a £35 crimper, normal pliers are fine.

The kit I had came with 50m of solar wire which was more than enough to go from inverters to panels - as I said connecting the panels together is the easiest thing imaginable.

Step six - launch!
Connect the energy monitors both to your normal meter, and your solar meter.

And then... turn on your inverter! With any luck within thirty seconds you will be generating your own, eco friendly, free electricity.

If for whatever reason it doesn't work you need to check your connections. Because the panels can be daisy chained and so the number of manual connections are limited, this should be easy. Each panel should output circa 40V, so just test each MC4 connector with a multimeter until you find the culprit.

Step seven - paperwork!
Within 28 days of free electricity, you need to notify your "district network operator" although if it is less than 4kWh it is essentially a paper filling exercise.


I hope that helps someone. I'm happy to answer any questions.
«1

Comments

  • agentk
    agentk Posts: 187 Forumite
    Eighth Anniversary Combo Breaker
    edited 20 February 2019 at 2:50AM
    Once you have identified a place to mount the inverter you just need to connect the AC side though the isolation switch (supplied with kit) into the meter (supplied with kit) and then connect it to anything on your sockets ring main. Despite the size of the inverter, the maximum it will kick out on a <3kw kit is 13amps, so it's not an issue.quote


    Oh dear & DC isolation.

    Why not just fit a 3 pin plug with a rusty nail as a fuse!
    3.55kw 2 systems 2.3 se 1.25 sw installed may 2011 and oct 2011..

    I have never been mis sold anything but i have bought a few things i didnt need!
  • Martyn1981
    Martyn1981 Posts: 15,210 Forumite
    Part of the Furniture 10,000 Posts Name Dropper Photogenic
    agentk wrote: »
    Once you have identified a place to mount the inverter you just need to connect the AC side though the isolation switch (supplied with kit) into the meter (supplied with kit) and then connect it to anything on your sockets ring main. Despite the size of the inverter, the maximum it will kick out on a <3kw kit is 13amps, so it's not an issue.quote


    Oh dear & DC isolation.

    Why not just fit a 3 pin plug with a rusty nail as a fuse!

    Yes, I think in the UK, the law requires that the system be hardwired into the consumer unit. It can't be plugged into a socket, nor connected to a ring main that has any other devices or sockets also on it.

    But the idea/advice for safely and correctly installed DIY PV is very useful. However I couldn't see any info on planning permission, which is needed if the panels don't match the pitch of an existing roof, or if mounted on a flat roof, or if wall mounted?
    Mart. Cardiff. 8.72 kWp PV systems (2.12 SSW 4.6 ESE & 2.0 WNW). 20kWh battery storage. Two A2A units for cleaner heating. Two BEV's for cleaner driving.

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • Obukit
    Obukit Posts: 670 Forumite
    agentk wrote: »
    Once you have identified a place to mount the inverter you just need to connect the AC side though the isolation switch (supplied with kit) into the meter (supplied with kit) and then connect it to anything on your sockets ring main. Despite the size of the inverter, the maximum it will kick out on a <3kw kit is 13amps, so it's not an issue.quote


    Oh dear & DC isolation.

    Why not just fit a 3 pin plug with a rusty nail as a fuse!
    I believe from the documentation with the inverter that the master inverter switch acts as a DC isolator in terms if minimum requirements in the UK.

    However, belt and braces I've fitted a three pole isolation switch outside, where the cables enter, and put the location on my consumer unit.
  • Obukit
    Obukit Posts: 670 Forumite
    Martyn1981 wrote: »
    Yes, I think in the UK, the law requires that the system be hardwired into the consumer unit. It can't be plugged into a socket, nor connected to a ring main that has any other devices or sockets also on it.

    But the idea/advice for safely and correctly installed DIY PV is very useful. However I couldn't see any info on planning permission, which is needed if the panels don't match the pitch of an existing roof, or if mounted on a flat roof, or if wall mounted?
    I'm not an electrician but as companies are selling "plug in solar" kits I assume its permitted. Of course in an ideal world you connect straight to the CU but as I said I wanted this to be portable.

    Logically bearing in mind you are removing rather than adding to the load its difficult to see any significant safety issues.

    I believe that only roof mounted panels are classed as permitted development so if you want to flat roof mount you need to get on okay with your neighbours.
  • mmmmikey
    mmmmikey Posts: 2,186 Forumite
    Part of the Furniture 1,000 Posts Homepage Hero Name Dropper
    edited 20 February 2019 at 12:24PM
    Hi


    I think this is a useful post and provides a good overview of what's involved in installing panels yourself. However, I have very serious concerns about the safety of your installation.


    When I fitted a new light fitting in my lounge a few weeks ago, I did what I always do and switched off the power at the main switch on the consumer unit to avoid any possibility of electrocuting myself. I know I could do this by just switching off the relevant lighting circuit, but that involves identifying the correct breaker, so I've always done this the belt-and-braces easy way by flicking the main switch.



    If I did that in your house, the lighting circuit could still be live if the sun was shining and as such I could have ended up electrocuting myself. For a grid tie inverter, that shouldn't happen, but there's loads of dodgy Chinese kit on eBay so you have to ask if your inverter is fully compliant and functioning. Sure, I could have switched off the inverter and/or the individual lighting circuit if I'd remembered to do so, but would I have remembered if I'd installed the panels 5 years ago? Would, say, a boiler repair engineer think to check for solar panels?



    My own solar panels connect to the incoming power side of the consumer unit, meaning that the consumer unit functions as expected and flicking the main switch kills the power to the house. I don't know this for a fact but I would imagine this is good practice and how this would be done in most if not all professional installations (i.e. meaning done by a qualified electrician fully aware of the relevent standards, not meaning to cast aspersions on your DIY skills).



    I haven't checked the regulations on this, but my point is you shouldn't assume that because what you've done doesn't need approval and works means that it is safe and good practice.



    Also, have you considered the implications of this work for your house insurance? In the event of an electrical fire (which may be unlikely) you may well find your insurers wouldn't pay out.


    I hate to pour cold water on this as I do think you've put together an interesting post. My suggestion would simply be that you (and anyone else thinking of doing this) employs an electrician to wire in the inverter. That doesn't stop the system being portable, but does give you a degree of confidence over the safety.


    Thanks, Mike
  • Martyn1981
    Martyn1981 Posts: 15,210 Forumite
    Part of the Furniture 10,000 Posts Name Dropper Photogenic
    edited 20 February 2019 at 1:40PM
    Obukit wrote: »
    I'm not an electrician but as companies are selling "plug in solar" kits I assume its permitted. Of course in an ideal world you connect straight to the CU but as I said I wanted this to be portable.

    Hiya, can I check that if you are not an electrician that the install was checked by one so that the DNO notification could be signed off by them?

    Regarding 'plug in solar' you are right, some companies do advertise them, but they are not legal in the UK, please see page 26 2.3.1 a.c. cabling:

    Photovoltaics in Buildings - Guide to the installation of PV systems.
    An inverter supplied from a PV array must preferably be installed in a
    dedicated circuit in which:
    ● no current-using equipment is connected, and
    ● no provision is made for the connection of current-using equipment,
    and
    ● no socket-outlets are permitted.
    An inverter must not be connected by means of a plug with contacts
    which may be live when exposed.
    Where an electrical installation includes a PV power supply system
    without at least simple separation between the a.c. side and the d.c.
    side, an RCD installed to provide fault protection by automatic
    disconnection of supply must be type B RCD according to BS EN 60898
    (IEC 60755, amendment 2).
    a.c. cables are to be specified and installed in accordance with BS 7671.

    Of course you could keep quiet and not tell anyone, but be advised that such an install of PV would void all your buildings insurance. So hardwiring it into the CU seems sensible on all counts.
    Obukit wrote: »
    Logically bearing in mind you are removing rather than adding to the load its difficult to see any significant safety issues.

    Think why all leccy connectors have the female end connected to the mains, and the male ends connected to the appliance, such as a lawnmower? You really wouldn't want to grab hold of the 'prongs' if they were live. Similarly (and I accept that the inverter should have shut down) but you don't want a plug that is connected to a live supply, such as a PV system, nor a ring main that has power coming into it, during a powercut.
    Obukit wrote: »
    I believe that only roof mounted panels are classed as permitted development so if you want to flat roof mount you need to get on okay with your neighbours.

    Correct, roof mounted PV is permitted development (in most cases), but the panels have to be at the same roof pitch, and mustn't increase the height of the roof. So they have to follow the roof pitch and stop short of the ridge tiles.

    For walls, and flat roofs, PP is required. Obviously putting slopped panels on a flat roof alters the pitch. PP is also need for ground mounts of 9m2 or more, but not for roof mounting on outbuildings (sheds, log stores etc) so a suitable frame for a triangular 'shed' gets around that problem.


    Can I also double check something here:
    Obukit wrote: »
    Most trade inverters require a minimum of 70V so you will probably have to wire them with at least two in series.

    If you have them at different angles/locations you should wire those groups in separate paralel circuits, because if they are in series a poorer performing group will affect the better performing one.

    If they are all in the same location it is easier if they are all in series.

    Firstly, and I apologise for the pedantry, but are you talking about higher voltage panels, say 72 cell panels, which might be 50V, as most panels are around 30V, so a string of two panels will struggle to meet minimum voltage. Also, it's important to check the minimum voltage of the MPPT too, as that is often higher, so strings of 4+ are usually needed.

    Secondly, you mention different angles, but does that inverter have more than one MPPT? I've looked for specs, and found 3 strings one MPPT, but I may have the wrong model. Whilst you can have more than one string on an MPPT (depending on the inverter make and model), all strings need to match and be balanced, so the same number of panels, same type, same pitch and same orientation. If you want varied pitches, orientations and panel numbers then micro-inverters are probably the route to take.

    Apologies again for pedantry, I think that's a great and detailed post, but due to some legal and technical concerns, I'm a bit too scared to thank it, sorry.
    Mart. Cardiff. 8.72 kWp PV systems (2.12 SSW 4.6 ESE & 2.0 WNW). 20kWh battery storage. Two A2A units for cleaner heating. Two BEV's for cleaner driving.

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
  • Obukit
    Obukit Posts: 670 Forumite
    edited 20 February 2019 at 1:50PM
    mmmmikey wrote: »
    Hi


    I think this is a useful post and provides a good overview of what's involved in installing panels yourself. However, I have very serious concerns about the safety of your installation.


    When I fitted a new light fitting in my lounge a few weeks ago, I did what I always do and switched off the power at the main switch on the consumer unit to avoid any possibility of electrocuting myself. I know I could do this by just switching off the relevant lighting circuit, but that involves identifying the correct breaker, so I've always done this the belt-and-braces easy way by flicking the main switch.



    If I did that in your house, the lighting circuit could still be live if the sun was shining and as such I could have ended up electrocuting myself. For a grid tie inverter, that shouldn't happen, but there's loads of dodgy Chinese kit on eBay so you have to ask if your inverter is fully compliant and functioning. Sure, I could have switched off the inverter and/or the individual lighting circuit if I'd remembered to do so, but would I have remembered if I'd installed the panels 5 years ago? Would, say, a boiler repair engineer think to check for solar panels?



    My own solar panels connect to the incoming power side of the consumer unit, meaning that the consumer unit functions as expected and flicking the main switch kills the power to the house. I don't know this for a fact but I would imagine this is good practice and how this would be done in most if not all professional installations (i.e. meaning done by a qualified electrician fully aware of the relevent standards, not meaning to cast aspersions on your DIY skills).



    I haven't checked the regulations on this, but my point is you shouldn't assume that because what you've done doesn't need approval and works means that it is safe and good practice.



    Also, have you considered the implications of this work for your house insurance? In the event of an electrical fire (which may be unlikely) you may well find your insurers wouldn't pay out.


    I hate to pour cold water on this as I do think you've put together an interesting post. My suggestion would simply be that you (and anyone else thinking of doing this) employs an electrician to wire in the inverter. That doesn't stop the system being portable, but does give you a degree of confidence over the safety.


    Thanks, Mike
    Hi Mike,

    Thanks for your post.

    The kit came with stickers to put on the consumer unit and meter reminding that it is dual supply and both must be isolated before working on the electrics.

    jubgix.jpg

    Its a Victorian house and to be honest I wouldn't do any work without turning off all the power in which case the inverter automatically cuts the power OR testing very carefully as you never know where people have connected circuits over the years.

    However, you are right that there is the risk if you rely on a circuit breaker and don't check the circuit is dead before starting work.

    Presumably every solar installation has the same risk though? I wouldn't like to be relying on the inverter cutting the power for sure.

    By the way not being defensive, genuinely interested on ways to improve from the experts on here :)

    Chris
  • mmmmikey
    mmmmikey Posts: 2,186 Forumite
    Part of the Furniture 1,000 Posts Homepage Hero Name Dropper
    edited 20 February 2019 at 1:51PM
    Hi again - although I'm advocating having this work done by an electrician, here's some additional information if it helps.....


    I've just looked, and my (professionally installed) system is wired as per yours up to the big red ac isolation switch and meter. From there a single 2.5mm2 T&E cable goes to a small, dedicated consumer unit in the meter box (the type of consumer unit you typically have in a garage or outbuilding). This protects the wiring and allows the solar system to be conveniently and safely isolated by anyone working on the meter etc.



    The other side of the mini solar consumer unit goes to Henley blocks on the house side of the main supply meter which connects it to the consumer units in the garage. (Note that I have 2 consurmer units as the house was originally wired for Economy 7).


    Also worth noting - there's a big warning sticker inside the meter box saying "Solar Panels on Roof".


    So I don't think there's too much to do to connect your system to the consumer unit, other than running a cable to the meter box or consumer unit, which compared to what you've already done shouldn't be too onerous.
  • mmmmikey
    mmmmikey Posts: 2,186 Forumite
    Part of the Furniture 1,000 Posts Homepage Hero Name Dropper
    ....I think we just crossed posts but hope my latest is useful :)
  • Obukit
    Obukit Posts: 670 Forumite
    Hmm, thanks. Looks like it is going to be best to wire it to the CU then.

    Was trying to avoid it if possible because the house is just a pain to run wires through.

    I was relying on this from the plug in solar website
    Can I Simply Wire My Plug In Solar Kit Into The Mains Circuit? Is It That Simple?
    Yes. Plug-In Solar can simply be wired into the Plug-In Solar Connection Unit that is provided with the kit. Under Part P building regulations (sections 2.7 and 2.8), the addition of a Fused Switched Connection Unit is classed as non-notifiable work (apart from in Bathrooms).
    Under the IET wiring regulations, an ‘electrically skilled’ person, who does not have to be a qualified electrician, can undertake the installation of a Plug-In Solar kit. All work must comply with the latest edition of the IET electrical installation wiring regulations, and if you are unsure please consult a professional*
    Why Can't I Just Plug It In?
    Under the IET wiring regulations you are not allowed to use a standard 3-pin plug to connect solar to the mains.

    Regulation 551.7.2(ii) states: “The Microgenerator (solar panels) must not be connected to the final circuit by means of a Plug and Socket”

    This is why we supply a Plug-In Connection Unit with all our kits. This ensures we abide by all the UK regulations.

    The idea that anyone would want to use a normal plug us a bit scary .
This discussion has been closed.
Meet your Ambassadors

🚀 Getting Started

Hi new member!

Our Getting Started Guide will help you get the most out of the Forum

Categories

  • All Categories
  • 349.8K Banking & Borrowing
  • 252.6K Reduce Debt & Boost Income
  • 453K Spending & Discounts
  • 242.7K Work, Benefits & Business
  • 619.5K Mortgages, Homes & Bills
  • 176.4K Life & Family
  • 255.6K Travel & Transport
  • 1.5M Hobbies & Leisure
  • 16.1K Discuss & Feedback
  • 15.1K Coronavirus Support Boards

Is this how you want to be seen?

We see you are using a default avatar. It takes only a few seconds to pick a picture.