DIY mounting solar panels on roof

[paulca]

tldr;

Need a good guide on the various hooks, rails, t-nuts, clamps, brackets etc. for fitting a solar panel to a pitched, tiled roof.


So my panel is sitting on a ground mount in the garden, but it is badly shaded by the house on the east side and the hedge on the west side.

The garage roof is only about 7 foot off the ground, maybe 12 foot at it's peek, so it will lift the panel out of the shade of the hedge and can be moved to the west side to get the sun as early as possible when it passes out of the shadow of the house.

I want to mount both the current 50W panel and a new 100W panel on the garage roof.  Probably in series, but that's a different topic.

The garage roof is a pitched roof with "double roman" concrete tiles.  I have found bits and pieces about how they mount to the tiled roof and I'm prepared to get up on the roof to mount them, as I said it's not that high and roof and worse case I fall off, I am only likely to break an arm or leg.  A set of indoor step ladders is enough to get up onto it and worst case I could plausible jump off safely.

I have figured out the hooks I need and that I need to "notch" the upper tile with an angle grinder.  New step is to find rails and panel mounting clamps/brackets/T-nuts etc.  This is where I've started to lose my google foo and all I can find are sparsely informative commercial offers simply trying to push "their" particular system.

Surely there have to be actual DIY guides on how to pick components that match and fit the panels to the roof.

I have tried paying people to do it, but the solar installers don't want the work, they only do full roof grid tie systems, sparks won't touch it and roofers won't touch it either.

[paulca]

This is the best I have found so far, from a chinese company.
https://www.gtsunsolar.com/pitched-roof-solar-mounting-for-roman-residencial-house_p19.html

Don't know if these component names and purpose translate well to other manufacturers though.

[fourtytwo42]

Hi I found there are loads and loads of variations!! One of the variables you need to also know is the thickness of your panels.

Could you post a picture of your tiles ? You should not have to cut them, there should be a system designed for them.

Don't forget the dreaded building regs and permitted development requirements, so you will have to calculate your loadings (there are websites for that) and check the roof structure too I know it all sounds a pain but better than having to take it down again.............

The biggest problem is finding someone selling DIY quantities, there are some on the bay BUT you probably don't want to travel to far with 4M rails bungied to your roof 

[Stray Electron]

  My advice is to keep your solar panels in your garden and off of your roof!  In the first place most roofs are not aimed in the optimal direction or at the proper pitch for solar panels so you will most likely lose a lot of efficiency.  But the bigger problem is that any attachments such as screws through the roof, will eventually leak and if you don't catch them in time the leaks can damage the roof trusses and any wooden sheathing.  (Ask me how I found this out!)  On top of everything else, if you put on a house roof then you have to consider the added wind and/or snow and ice loading. 

[Someone]

My advice is to keep your solar panels in your garden and off of your roof!  In the first place most roofs are not aimed in the optimal direction or at the proper pitch for solar panels so you will most likely lose a lot of efficiency.  But the bigger problem is that any attachments such as screws through the roof, will eventually leak and if you don't catch them in time the leaks can damage the roof trusses and any wooden sheathing.  (Ask me how I found this out!)  On top of everything else, if you put on a house roof then you have to consider the added wind and/or snow and ice loading.

I'm not sure if you didn't read the OPs post or just don't have any experience of the rest of the world, but possibly nothing in here applies to their situation.

This is the best I have found so far, from a chinese company.
https://www.gtsunsolar.com/pitched-roof-solar-mounting-for-roman-residencial-house_p19.html

Don't know if these component names and purpose translate well to other manufacturers though.

That is a common style of system and the roof brackets can be swapped out to suit different situations. Sliding between the roof tiles you're not making any new holes in the roof, but consider carefully how to pass any cabling back into the house so that its held still and won't abrade the insulation.

You can source the parts direct from where ever they are manufactured, or try and find a local wholesaler, its unlikely electricians or roofers are importing them or buying in large quantities. There will almost certainly be some local shops with the parts available either in modular kits or piece by piece.

[paulca]

I didn't consider building regs.  I'll have to look into that.  The garage is detached from the house, so I believe that cuts me some lea way on a lot of things as opposed to an attached garage which must meet the same regs as the house.  To be honest, I'm not even sure I can't just "wing it".  Worst that will happen is someone complains and doesn't like them and local council says I need to take them down again.  That's unlikely though the only people who will see them are my immediate neighbours.

Finding small quantities will be a challenge.  I can find roof hooks on ebay/amazon, but not rails and haven't looked for the clamps et al.

It's presently an unheated and mostly unsealed garage, though it's dry.  So I might just resort to slipping the cables up between a seam in the underfelt.  There is actually a huge hole in the underfelt already where my oil burner flu used to be, I could just use that.

So I don't need to be anywhere near as careful as I would if this was the house roof.  That is on the list, but I will wait till I see if the government changes and provides incentives or wait until I can budget a proper 4k roof system and get that installed by a professional company, get full electric board grid tie certified system.

[fourtytwo42]

Hi Paul, I think you can wing it as long as it looks pro and you can show your loading calcs to anybody who turns up lols
I seem to have mislaid the web refs but if you search for MCCS certification you can come across some docs that specify exactly what's required.
In the meantime here is an excerpt from one of my docs giving details of suppliers etc for mounting stuff, I eventually bought it from the same guy who was selling of panels in Colchester but he is no longer in business AFAIQ

2.3.4   Mounting components
There are several different systems with different profile rails and they are NOT interchangeable. All prices inclVAT, excl shipping (MOQ in brackets).
The ones we now have are by CLENERGY (stamped on hooks) http://clenergy.com/.
System   From   ~3M rails   Tile brackets   Mid clamps
K2   dragonsbreathsolar
£10.60(2)   £5.22(5)   £1.26(20)
Schletter   windandsun
£16.45(1)   £12.04(1)   £1.43(1)
VFM   vfmsolar
£10.30(1)   £4.52(1)   £0.83(1)
Fischer   Ebay   4M/£22 incl deliv(1)   £6(1)   £0.99(1)
Fastfix   Ebay   2.1M/£40 incl deliv(1)   £30(1)   £4(2)
Given high MOQ of mid clamps, adapt them as end clamps as well.
Based on the K2 system and MOQ’s a 2 rail(3M) installation will cost £72.50 excl shipping, add at leat another £5 for screws & bolts. This could be extended to 4M for an extra £7.
This site mountsolar has an unpriced system BUT a useful loading calculator, this is very useful as it shows we must use 6 roof hooks on 3M span (see tif file).
A 4M (using 5.8M rails) from VFM (3 brackets/rail) and 4 end + 4 centre clamps (4 panels) would be £83 + carriage.
2.3.4.1   Hook spacing
Max allowed span is 1600mm & end overhang is 400mm, this means a 4M system requires only 3 hooks per rail.

Hope you can decipher all that

[paulca]

Thanks very much 42.

I did a quick check for building regs here in Northern Ireland and I see that for pretty much all building except nuclear shelters (WTF?) and small plant houses are covered.  However...  the building regs are really only required to get your MCS cert for Microgen grid connection.

So for now I'll just wing it.

Your list helps a lot, so I will start contacting suppliers.

The most I expect to put up there is 3x100W panels.  I'll leave the 50W in the garden for now, or just sell it as it's going to make it awkward to mount without using 3 rails, although I'll double check to see if I can get away with 2 rails clamping the 50W right on it's edges and mid-points on the 100W panels.

So I probably only need 2 meters of rails (2 sets of 2 meters). 

I suppose it's probably a good idea to buy clamps for all 3 panels, ie 8 clamps in advance rather than trying to source them later when I add a panel.

Good idea on the end clamps.

[paulca]

So based on your figures for up to 3 100W (Renogy for now) panels which are 1074 x 498 x 35mm means I need rails 1500+mm long.

My 50W panel is 676 x 571 x 30mm, so if I measure my roof tile spacing and can find a way to put the hooks, say roughly 600mm apart, I should be able to mount this as well.  So starting with 1x100W and 1x50W and if I upgrade I can go 250W then 300W and remove the 50W panel.

This would have a 200mm overhang vertically on the 100W panels.  I'll position them so there is even spacing above towards the peak and below towards the eves in case future panels are larger.

So I would need:
4 x portrait hooks w/ rail T nut fixings (+ rafter screws )
2 x 2m rails ( + end caps )
8 x panel clamps

I also need to get some MC4 connectors for my 50W panel and an MC4 distribution box for 3 panels or just MC4 Y connectors to provide the ability to wire in parallel or series. 

I believe I can use 100+50W in parallel @ 12V with my existing charge controller, giving short circuit amps of around 9.38Amps into a 10Amp charge controller.  Series doesn't really get me anything as the controller is limited on the 12V charge side to 130W as follows - the controller only support 130W @ 12V charge power but will self limit if the panels exceed this, as long as they don't exceed 50V or the rated 10 Amp.  For more I need to go to a 24V battery system when it supports upto 260W.  I could also upgrade the controller later if need be.

EDIT: On the tiles, they are very close to these:
https://www.marley.co.uk/products/concrete-tiles/double-roman

The angle grinder is required as the overlap of the tiles sit flush against each other, if you have to bring the hook bar though there it makes the upper tile sit proud.  The grinder and a stone disc can "notch" the tile to allow the upper tile to sit properly.

Also.. "MidsummerWholesale" confirmed on the phone that they will do small low quantity orders for domestic customers, they deliver to Northern Ireland have the  option of a Dublin branch if that makes shipping cheaper for me.  They do several different setups to choose from.

[SpeedyDave]

I have just been thru this, I am in Oz.

Here are my findings.

Over the last 10 years, there have been many types of rail profile developed, and each rail has its own unique mounting hardware.

Here in Australia, the tech is at a point where people are removing "old" systems and upgrading.
Because the rail profiles have changed, they are no longer upgradable, and so people just remove every thing and start over.
So for me, the second hand market was the easy and cheap choice. (for Panels as well)

One thing to really pay attention to is your areas weather/wind.
Wind loading on the panels can be large, and so following the guidelines is strongly recommended.
So is rail end overhang (the amount of unsupported rail, after the last roof bracket) is important, as well as the rail spacing, so that the panels are clamped down in the correct areas.

I've attached some docs that you should be able to relate to your local weather.

The SunLock install manual is very helpful with the tech aspect of mounting.

[Red Squirrel]

Roof top is a pain, especially if it's not a steep roof, because it's very hard to see the panels, and reach them with a long pole to take the snow off every morning.  I have a small setup on my shed as a pilot project as I have no yard room for a ground mount and I've come to the conclusion that I really need to automate the snow removal process if I want to do the house.  So if you have the room for ground mount then stick with that as they are easier to access.

That said, for racking what I used is PV Quickmount mounting system, and Unistrut for the actual rails.  I have a video here of the installation:



Bought the PV Quickmount here: https://www.modernoutpost.com/product/qmse-quick-mount-e-mount-pv-roof-attachment-mill/

Unistrut I got at Nedco locally.

One of the main reasons I went unistrut is that it's a more established standard.  I feel there's lot of racking systems for solar but will they be around in 5, 10 or 30 years from now?  Will I still be able to get parts if I want to upgrade or modify something?  Even if the PV Quickmounts change, as long as I have something that involves a giant bolt sticking out I can always put unistrut on it.

[SpeedyDave]

We don't get much snow here.

Cement tiles on timber rafters and battens. 17 degree pitch.

All either stainless steel or anodized aluminium (no rust here)

A nice bright day yesterday saw 46.8kWh generated 

Inverter ran at full power (5kW) from 9am till 3 pm.

[SpeedyDave]

11 panels due west

[SpeedyDave]

11 panels due east



east and west strings are paralleled via diodes at the breaker before feeding into one of the MPPT's of the inverter

Another 20 (2 parallel strings of 10) due north

all panels are 190watt Suntech

Oh, and NO SHADE

[Red Squirrel]

Nice setup!    Wish I had that much roof room but my house is awkward as it's split level,  though snow is still a huge issue here but with a big enough system I would just figure out a way to automate it better.  The shed one is just for fun so not worth spending too much time on it.

We got some wet snow and freezing rain the other day which turned into ice so my panels are more or less out of commission till May-June now.   My driveway is an even bigger mess, have to wait till the jagged ice gets packed in with hard snow before I have a smooth driveway again.

[SpeedyDave]

Certainly a different set of issues than we have here.

Our biggest is temp degradation of the panels.

When ambient is pushing 45 degrees, the panels can be well over 70.  I can actually see the drop off in performance !

I have heard that PV solar panels are electrically just like a string of diodes.
I heard that if you reverse bias them with a current limited supply, the heat dissipated will melt the ice/snow, leaving them able to function correctly.

That might make for an interesting project !

[rs20]

I have heard that PV solar panels are electrically just like a string of diodes.
I heard that if you reverse bias them with a current limited supply, the heat dissipated will melt the ice/snow, leaving them able to function correctly.

That might make for an interesting project !

One of the "ideas" behind solar roadways...

[Red Squirrel]

Certainly a different set of issues than we have here.

Our biggest is temp degradation of the panels.

When ambient is pushing 45 degrees, the panels can be well over 70.  I can actually see the drop off in performance !

I have heard that PV solar panels are electrically just like a string of diodes.
I heard that if you reverse bias them with a current limited supply, the heat dissipated will melt the ice/snow, leaving them able to function correctly.

That might make for an interesting project !

Yeah I had started a thread last year asking for suggestions and that came up.    One thing I think I will eventually experiment with though is nichrome wire. (or just thin wire really) and sending a current through it.   That way I have better control over the heat and I don't risk damaging the panels if I put too much voltage on it.    Essentially I would stick nichrome wire and a temp sensor then glue foam board and ramp up the voltage slowly until it hits a certain temp point.  I'd lose a bit of efficiency in summer but not really a huge deal as the days are super long for those months and summer itself is very short.   Would not melt all the ice but perhaps melt it enough that I can go in with the brush and make it slide off.

Really what I need to do is just tilt them vertical, but I do worry it might make them act like a sail and put too much force on the roof mounts, but it would be the best solution for me I think.

[fourtytwo42]

EDIT: On the tiles, they are very close to these:
https://www.marley.co.uk/products/concrete-tiles/double-roman

The angle grinder is required as the overlap of the tiles sit flush against each other, if you have to bring the hook bar though there it makes the upper tile sit proud.  The grinder and a stone disc can "notch" the tile to allow the upper tile to sit properly.

Hi Paul I reckon our tiles are the same, mine have been up since ~1975, the enclosed pics attempt to show what happens if you don't cut the tiles.
On my roof at least the tiles do not fit perfectly and there are often quite big gaps in the overlap (see last pic), this is partly caused by the thin warped woodwork underneath that seems typical of today's house construction. In the end I used a hammer and vice to bend the hooks to the twist of the wood at each hook location, most times the tile was almost as flat after the hook was fitted as before, where I considered the gap excessive I filled it with outdoor mastic. If your array fills your rails then all the hook locations will be under the panels anyway so only need to be drip-proof rather than driven rain proof. This solution suits me but probably not everybody 

[paulca]

Thanks guys.  We don't get much snow here, well, one or two days a year with maybe one year a decade when we get a prolonged few weeks of snow.  We also don't get extremely hot weather I think the record here is only 29*C or something.  We do get a lot of rain and a lot of wind though.  Also within sight of the sea putting salt in the air.

I think wind loading is my biggest consideration and checking that the hardware I buy is aluminium or genuine stainless to hopefully keep the fixing from rusting, binding or rotting.

On the wind loading, it's a low rough sheltered by houses, and as I'm only planning on mounting a small 2 meter x 1 meter array (3x1 small panels) So 4 hooks, 2 rails with equal 1/3 hook spacing should be over spec.  The rails will hopefully result in maybe 200mm over hang on the large panels and zero on the smaller one.

Basically I want the garage and garden to be off-grid low voltage solar.  With the exception being the laundry equipment of course as that has to run on mains.  So it will only be running some lights intermittently. 

The reason I need to do this and probably soon is my 100Ah marine battery is dying just running the charge controller and the Wifi monitor box.  We have got that little sun that my peak watts for the past fortnight has been 1 hour at 23Watts and most days it barely gets to 5W, yesterday it peeked at 0.85W!  The low winter sun is shaded by the house, the neighbours wall and my hedge so it only sees the sun for a few hours.  So the battery voltage is falling slowly each day.  I will soon have to use a DC wall wart to run the garage lights to do the laundry!  Up on the garage roof I believe it will get twice the sun hours due to less shading.

For proper solar, when I pay off the new heating system I will hopefully get an interest free loan around £4000 and get an actual solar installation company to put a 3-4k system on the roof with proper certificates and grid tie.

[SpeedyDave]

Good luck !
It is very satisfying when your ideas and tinkering achieve results.
With a 5watt generation though, you have some issues to overcome, but don't give up, it will be worth it !

As an indication of what clear late spring days can do down here, my system generated 47.17 kWh yesterday   

[bdunham7]

As an indication of what clear late spring days can do down here, my system generated 47.17 kWh yesterday 

Say what?     I've been following along and I thought you had 22 panels and a 5kW inverter--that seems like an impossible amount of power for one day...

[SpeedyDave]

42 panels in total, feeding an SMA SB5000TL inverter ( 5kW with two MPPT's)  see post # 13

11 east
11 west  *** I've actually got 12 panels connected as part of my experiment *****
20 north ( 2 strings of 10 panels, paralleled )

I had only been talking about the east and west strings, as they are the focus of my experiment to parallel two different strings using blocking diodes.

Sorry for the confusion

[paulca]

I still haven't put my panels on the roof yet.  However, after having to use the battery charger for a few hours on it two weeks in a row while doing the laundry I happened to look outside at noon.

The panel is actually below the shadow line of the neighbours fence!  So it was never actually seeing the sun at all since maybe early November.  Hence it never got above 5W when it was fully sunny.  Duh!

Plonked it up on the garden table, angled the panel much more upright to a fresh winter sunny day and ... wham, 28Watts!  Might get a few more if I give it a wash.

That will cover me until I get round to mounting them up on the garage roof.

The kit to mount on the roof came out at £102, but shipping is £42!  Need to see if I their Dublin branch can ship cheaper.