Solar panels and battery - any real world reccomendations?

Yes, fitted it myself. Probably shouldn't have - but wasn't particularly difficult. Just waiting on an extra bit of trim for the trunking and some more appropriate cable for the grounding cable.

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It's not a par on what Ronski is doing. I've only really connected up a couple of well engineered and relatively safe commercial products using quite a fairly well documented installation guide.

Today I made myself up a custom 'smart meter' for the battery out of my daughters old £45 Chinese phone and a 3d printed enclosure. Needs a bit of black paint to tidy it up.

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From what I read technically any generation or storage over 1kwh is notifiable to the grid (local DNO), assuming its grid connected and not standalone such as in a shed.
Also I believe fully notifiable to local building control

As ever you pays your money and takes you choice.

The inverter(s) will shut down with no grid signal anyway (default setting).
I suspect the main drivers for grid wanting to know are 1) should it NOT isolate itself they know the properties within an area that could be the issue, 2) obviously the issue with local cabling if many people exported.
 
I'm off to read the entire thread, but if someone wants to give me some quick answers/guide on the below that's cool:

1: We use about 20kwh a day average on elec. I consider this high usage. Is this fair to say?
2: Would we benefit from solar and is it feasible on our property (more info below on our house)
3: Does solar installation have to have large wires going back to the main electric box where electricity enters the property and/or the main fuse box?
4: What rough cost are we looking at and what should I start looking at in terms of product specs?
5: If we got an install on the loft converted dormer flat roof, would the panels need to be tilted towards the south or could they function lying flat?


Our house is an end of terrace 4/5 bed house with a loft conversion. In the below image, down = south.

Green = loft conversion flat roof.
Yellow = Converted garage with pitched roof facing east and west.
Orange = extended lower roof kitchen in shade until later in day
blue = Shed roof with very slight pitch angle but mostly flat
red = pitch area of original roof mostly always in shade
pink = pitch area of original roof more in light
purple line is just the whole rough property line including garden and drive


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The first 14.4 KW's of my DIY install. Its really good fun building this type of thing.

Monitored/run/configured via Raspberry Pi and Victron VenusOS

Ordered the 4th JK BMS yesterday for 4th battery build.

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jaybee said:
I'm off to read the entire thread, but if someone wants to give me some quick answers/guide on the below that's cool:

1: We use about 20kwh a day average on elec. I consider this high usage. Is this fair to say?
2: Would we benefit from solar and is it feasible on our property (more info below on our house)
3: Does solar installation have to have large wires going back to the main electric box where electricity enters the property and/or the main fuse box?
4: What rough cost are we looking at and what should I start looking at in terms of product specs?
5: If we got an install on the loft converted dormer flat roof, would the panels need to be tilted towards the south or could they function lying flat?
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1: Not really. Electric usage is only ever really going to increase when you factor in heating, EVs etc.
2: If you have a roof, you'll benefit. Will it be cost effective - definitely in the long run. But some of the prices I'm seeing being charged recently will take years to recover.
3: It has to have wires and they have to get to your main consumer unit. How large depends on a number of factors.
4: Most quotes are looking between £10k and 20k - but this is highly variable depending on what spec you want.
5: I don't think most installers would want to add panels to a flat roof loft conversion. Angle is important for efficiency - but so is not damaging the dormer.

My guess, they'd likely suggest putting an EW array on your converted garage. Most hybrid inverters can take two strings, so is quite an easy cost effective way to do it. Not working at height should also be cheaper (but depends on the installer).
 
jaybee said:
I'm off to read the entire thread, but if someone wants to give me some quick answers/guide on the below that's cool:
Click to expand...

Ideally you want panels on the highest roof you can get with the least shading. Rooftops can shade each other.

E facing = earlier generation.
S facing = best central generation.
W facing = later generation.

E and W facing will never do the same generation as S facing.

Optimal roof incline is 30 degrees. More or less can work but will do a bit less. E or W facing perfectly at 30 degrees with no shading would do about 80% of the same panels on a perfect S facing 30 degree roof.

Mixture of panel orientations can work well, if you can do all 3 and make it work, that could be an idea.

You will need to run cabling to a central inverter or two, and these must be connected somehow back to your main CU, as I understand it.

Consider optimal location for inverter/battery and work the rest backwards. Might be that your garage would be ideal location for the main components.

Flat roof definitely adds more complexity, and may need planning permission depending what you're doing. Although if you have a pitched roof at a higher level than the flat one, it may also be OK.

As a rule of thumb, a good 1kW of panels on a decent location will generate roughly 1kWh per year. 20 kWh per day usage and you're looking at 7300 kWh usage per year. You probably want about as many panels as you can get here. May as well go big or go home. Gun for a 7-8kW of panels if you can.

If considering battery storage you want probably at least 50% of usage as storage, so 10kWh would be good, more can give you better utility in the winter if you can get onto something like Go with cheap charging overnight.
 
Why is it more complex doing it on a flat roof? Why would that need planning? The flat roof is almost at the same height of the absolute highest pitch part of the main roof so very high.
To be honest, I think my garage roof might be in shade by next door at certain points of the day, especially in winter. May have to look into that first.

HungryHippos said:
.....

As a rule of thumb, a good 1kW of panels on a decent location will generate roughly 1kWh per year. 20 kWh per day usage and you're looking at 7300 kWh usage per year. You probably want about as many panels as you can get here. May as well go big or go home. Gun for a 7-8kW of panels if you can.

If considering battery storage you want probably at least 50% of usage as storage, so 10kWh would be good, more can give you better utility in the winter if you can get onto something like Go with cheap charging overnight.
Click to expand...

Run that maths by me again? Are you saying a SINGLE panel produces 1kw per year!? Can't be right. Per year? As in, with 7/8 panels I'd generate less than half a days worth of my daily elec usage... per year!?
 
jaybee said:
Why is it more complex doing it on a flat roof? Why would that need planning? The flat roof is almost at the same height of the absolute highest pitch part of the main roof so very high.
To be honest, I think my garage roof might be in shade by next door at certain points of the day, especially in winter. May have to look into that first.



Run that maths by me again? Are you saying a SINGLE panel produces 1kw per year!? Can't be right. Per year? As in, with 7/8 panels I'd generate less than half a days worth of my daily elec usage... per year!?
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Apologies I meant 1kW (2 or 3) panels would generate around 1000 kWh per year.

Planning permission may be needed if the roof height is going higher than the current height. Which it will if you're adding panels on mounting brackets at an angle!

If panels on brackets at the highest point are below the pitched height you may be OK, best to seek advice from the experts.
 
I can't see an easy way of running wires back from my garage roof, or in fact any external part of the house, back to the main consumer unit which is by my front door in the downstairs toilet, without having great big ugly black wires stapled to the brickwork on the outside if the house. Got enough black wire on the outside of my house as it is! :O I guess I could have it all in the loft space above the garage and then somehow run a wire back to the consumer unit but that is a horrible job. It would have to go through multiple ceilings and lift up several carpets and floors from above. In fact, it's not realistically possible internally I don't think. Hmm.
 
Mercenary Keyboard Warrior said:
Planning rules limit panels installation
If roof is east or west facing flat is best
If its south facing best is 30-40 degrees
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So I have the worst of both, flat which would be good for south (but I suppose they could be tilted, but would look awful from a distance.)
And then East/west I have a garage roof pitched.
Assume I could get an install for 10k, it would definitely take years. We use about £2800 a year elec on current projection. Assume I had an install even generating half that (over 3500kwh per year, not sure if doable), it's going to take 7 years to pay back by my very quick man maths.
 
There's two types of wiring. The DC cabling that will carry power from your panels to the inverter. The inverter could be mounted anywhere. Then there has to be a connection from the inverter to your main consumer unit. Being AC, this doesn't require the same kind of thickness. But, that does depend on system size.

I'm sure any competent installer would be able to do it quite tidily.
 
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