Corner turned

[Joeboy]

Lots of edge scatter from the clouds here today and getting some good consistent figures over 2kWp dropping to around 800Wp as the heavier clouds pass.

Bypass is steadily heating up the radiators and tube heaters around the cottage and the base temperature is 18 degrees.

I definitely need some additional panels to spread around on the shoulder days/ months when he solar is a bit more patchy so that I can both be consuming and charging for later as the people with larger arrays do.

Moxi

Sounds like a good idea. I plagiarised Nowty's setup, he's a good egg and helped me out plenty through the process. I honestly can't praise the combo of (Nowty), an oversized array and battery/storage system enough. All the worry just falls away and managing the pv to maximise home use becomes a lot less frantic.

Add to that a raised awareness of power consumption and home sealing/insulation and suddenly that oversized array in marginal conditions is doing the job of pushing back the shoulder months. Very satisfying indeed.

[Stinsy]

I definitely need some additional panels to spread around on the shoulder days/ months when he solar is a bit more patchy so that I can both be consuming and charging for later as the people with larger arrays do.

It is important to understand the pros and cons of an oversized array. In winter you still don’t see any noticeable benefit. You might use 20kWh of electric and 30kWh of gas in a day while your 4kWp solar array produces 1kWh (or less!). Even having an array 2x or 4x the size won’t make any discernible difference. In summer you won’t make use of the additional power. The same 4kWp array might produce 25kWh on a really sunny day. But seeing as you’ll need no spaceheating on those days, you’d probably struggle to use the power you’re already generating any additional provides little benefit.

It is easy to sit here mid-April on a rare cold-but-sunny day and imagine a slightly larger array being put to good use, but how many days a year is that really the case?

Don’t get me wrong, if I had room for more panels I’d be scheming. But you should be realistic about the diminishing returns.

[Joeboy]

I definitely need some additional panels to spread around on the shoulder days/ months when he solar is a bit more patchy so that I can both be consuming and charging for later as the people with larger arrays do.

It is important to understand the pros and cons of an oversized array. In winter you still don’t see any noticeable benefit. You might use 20kWh of electric and 30kWh of gas in a day while your 4kWp solar array produces 1kWh (or less!). Even having an array 2x or 4x the size won’t make any discernible difference. In summer you won’t make use of the additional power. The same 4kWp array might produce 25kWh on a really sunny day. But seeing as you’ll need no spaceheating on those days, you’d probably struggle to use the power you’re already generating any additional provides little benefit.

It is easy to sit here mid-April on a rare cold-but-sunny day and imagine a slightly larger array being put to good use, but how many days a year is that really the case?

Don’t get me wrong, if I had room for more panels I’d be scheming. But you should be realistic about the diminishing returns.

A fair point yet I disagree as the oversized is a massive difference maker, obviously it can't cover everything (Dec & Jan are woeful for me as theres nothing to harvest). I'll screengrab a photo of my solar graphs and show the gains I have seen for posterity and assistance. I am using everything I am producing..

[Stinsy]

I definitely need some additional panels to spread around on the shoulder days/ months when he solar is a bit more patchy so that I can both be consuming and charging for later as the people with larger arrays do.

It is important to understand the pros and cons of an oversized array. In winter you still don’t see any noticeable benefit. You might use 20kWh of electric and 30kWh of gas in a day while your 4kWp solar array produces 1kWh (or less!). Even having an array 2x or 4x the size won’t make any discernible difference. In summer you won’t make use of the additional power. The same 4kWp array might produce 25kWh on a really sunny day. But seeing as you’ll need no spaceheating on those days, you’d probably struggle to use the power you’re already generating any additional provides little benefit.

It is easy to sit here mid-April on a rare cold-but-sunny day and imagine a slightly larger array being put to good use, but how many days a year is that really the case?

Don’t get me wrong, if I had room for more panels I’d be scheming. But you should be realistic about the diminishing returns.

A fair point yet I disagree as the oversized is a massive difference maker, obviously it can't cover everything (Dec & Jan are woeful for me as theres nothing to harvest). I'll screengrab a photo of my solar graphs and show the gains I have seen for posterity and assistance. I am using everything I am producing..

Im not disparaging your array! And right now is when it really pays off. If you’re getting 2x or more of your kWp in kWh while you still need spaceheating then you really are golden.

You obviously have a lot going for you with your big-battery BEV and hot tub but I’ll be interested how you manage to use the power your big array generates 50kWh for several successive days in midsummer. I know it is a classy problem to have (more free energy than you can use) while everyone else is paying silly prices, but my point about diminishing returns means the bigger the array the harder it is to find a productive use for the power on the sunniest days.

[Joeboy]

It is important to understand the pros and cons of an oversized array. In winter you still don’t see any noticeable benefit. You might use 20kWh of electric and 30kWh of gas in a day while your 4kWp solar array produces 1kWh (or less!). Even having an array 2x or 4x the size won’t make any discernible difference. In summer you won’t make use of the additional power. The same 4kWp array might produce 25kWh on a really sunny day. But seeing as you’ll need no spaceheating on those days, you’d probably struggle to use the power you’re already generating any additional provides little benefit.

It is easy to sit here mid-April on a rare cold-but-sunny day and imagine a slightly larger array being put to good use, but how many days a year is that really the case?

Don’t get me wrong, if I had room for more panels I’d be scheming. But you should be realistic about the diminishing returns.

A fair point yet I disagree as the oversized is a massive difference maker, obviously it can't cover everything (Dec & Jan are woeful for me as theres nothing to harvest). I'll screengrab a photo of my solar graphs and show the gains I have seen for posterity and assistance. I am using everything I am producing..

Im not disparaging your array! And right now is when it really pays off. If you’re getting 2x or more of your kWp in kWh while you still need spaceheating then you really are golden.

You obviously have a lot going for you with your big-battery BEV and hot tub but I’ll be interested how you manage to use the power your big array generates 50kWh for several successive days in midsummer. I know it is a classy problem to have (more free energy than you can use) while everyone else is paying silly prices, but my point about diminishing returns means the bigger the array the harder it is to find a productive use for the power on the sunniest days.

I know that Stinsy, sometimes nuance gets lost in these typings, would be much easier if we were all in the pub!

Sept 20 the 1st part (half) of the new array went live, by Sept 21 the second half was in and live. This is the first Summer when we'll have had a full run at it. The Feb & march graphs show it well.



As you say, there's not that much point in adding a large amount of extra PV unless you can utilise the power. At the moment I am still taking from the grid overnight for spaceheating and to top up the stack, most of which I chuck at the EV the next morning if the sun shines. For anyone looking to enlarge i'd say its worthwhile but only after insulate, insulate, insulate. I am also a massive fan of storage heaters as you know. Having a 38kWh place to put the excess power has been handy and as the temps are still low this far North its a boon. Our total storage cap is 137kWh, If i hit that as a cumulative build up in Summer I'll be surprised (pleasantly)!

The weakness in our system is that when we go on holiday then the second array shuts down, doesn't export so no benefit. Just one of those things so we compensate by getting our son to use the place as much as he wants in our absence. At least that way his Octopus bills are lower.

To the end of March 22 the second array has generated 2.179MWh of power, that figure would be over 2.5MWh easily if i could have kept it on song the whole time. Scottish power charge 19.09p per kWh on the standard contract so that's £415.97 of my investment back, £470 if i'd not went holidaying. The second array cost about £2,500 give or take and allowing for the cost of the Victron and fuse upgrade during the second half expansion of the second system (it makes sense if i read it)!

As the second system went together in three stages I can't draw precise lines on the figures but I can say that Oct 20 to now is 1.5 years with the entirety of the system never seeing a full run at it. Nonetheless and even with the holidays and system shutdowns due to that we have seen a 16.6% return of our original investment or 11% pa. I can't stress enough how slanted that figure is towards poor performance, it is literally worst case to present as its patchwork build over time so can't see the true performance from day 1. Day 1 being Oct so not exactly a stellar month going into A Scottish Winter (that's two Scottish Winters on the 1.5 year timeline). Combine that with Leylandi shading, system shutdown due to my absence and it still manages to return 11% pa. On top of that are the extras costs of changing out the controller and fuses as I went larger. This isn't a brag btw, but if there's someone out there looking to expand their system this is a real world take on what to expect, Cheers!

I have bought a 20mtr run of 4mm PV cable so will make one 1/4 of the second array a moveable groundmount, would be smashing to see 1MWh in one month (June) but I'm going to be over in Europe with my son then and can't see SWMBO dragging a groundmount about to chase down a figure..

Last thing, If i was set up in Optimal or close to conditions in Southern England I reckon this system as a diy install firing on all cylinders from day 1 would pay itself back easily in under 5 years.

[Moxi]

My comment for additional panels comes off the back of realising that I’m not yet at a position where I can get sufficient space heating and recharge the batteries and all of that’s before I even investigate further how to manage to fit some form of electric powered or electric assisted DHW system in.

I’m fitting 2.3kWp in roof on the annex for the parents with a 4.4kWh battery to get them closer to being grid neutral part of the year and I bought us and them shares in WT 2 so that’s stacked away to help out in the winter once built and commissioned.

But there’s still a few places where I could sensible place individual or panel pairs to harvest a few more Wp and I have learned from my mobile array that a few panels that can be moved from point to point and angled according to needs can be more efficient than a whole roof of panels in certain conditions.

Equally I think my position is idea for a micro wind turbine but I’m not willing yet to experiment with that option while there’s scope for more panels.

Moxi

[AE-NMidlands]

it would be interesting to hear an answer to

I’ll be interested how you manage to use the power your big array generates 50kWh for several successive days in midsummer.

Can us newbies/yet-to-starters assume that in summer when the batteries are full and the cylinder is hot too the pv just stalls, apart from exporting whatever your permitted amount is? I can see that (if you have the money for panels and the controls needed) over-sizing is brilliant if you want to extend your off-grid/export period, but what does happen in midsummer?
A

[Joeboy]

it would be interesting to hear an answer to

I’ll be interested how you manage to use the power your big array generates 50kWh for several successive days in midsummer.

Can us newbies/yet-to-starters assume that in summer when the batteries are full and the cylinder is hot too the pv just stalls, apart from exporting whatever your permitted amount is? I can see that (if you have the money for panels and the controls needed) over-sizing is brilliant if you want to extend your off-grid/export period, but what does happen in midsummer?
A

If the system is grid tied it exports to grid once home demands are all satisfied. If it is an off grid system it switches off. The game is entirely in keeping the SOC of the battery stack sub 100% so the off gird system continues to generate. I have both systems as do others here yet each owners setup is unique to their lifestyle. It really is like a custom made suit.

[Fintray]

it would be interesting to hear an answer to

I’ll be interested how you manage to use the power your big array generates 50kWh for several successive days in midsummer.

Can us newbies/yet-to-starters assume that in summer when the batteries are full and the cylinder is hot too the pv just stalls, apart from exporting whatever your permitted amount is? I can see that (if you have the money for panels and the controls needed) over-sizing is brilliant if you want to extend your off-grid/export period, but what does happen in midsummer?
A

Apart from trying to use as much as possible (in a useful way) my system limits the export. Might be ok if you needed air conditioning to keep your house cool during summer (not a problem up here!) so more would be used. The main advantage for a larger PV system is the extra kWh during the colder months:
Averages for each month
Oct - 18.8kWh/day
Nov - 9.2kWh/day
Dec - 6.2kWh/day
Jan - 10.2kWh/day
Feb - 20.0kWh/day
Mar - 32.2kWh/day

[nowty]

it would be interesting to hear an answer to

I’ll be interested how you manage to use the power your big array generates 50kWh for several successive days in midsummer.

Can us newbies/yet-to-starters assume that in summer when the batteries are full and the cylinder is hot too the pv just stalls, apart from exporting whatever your permitted amount is? I can see that (if you have the money for panels and the controls needed) over-sizing is brilliant if you want to extend your off-grid/export period, but what does happen in midsummer?
A

Nothing bad happens, once everything is full as long as you have a G100 export limiter the inverter throttles the power from the panels back like a dimmer switch turning a light down.

If you don’t have export limitation then the export increases until either the export maxes out or the higher AC output voltage trips out the inverter.