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Solar Panels UK - is it worth it?
- Thread starter jdwuk
- Start date
we have a 30kw array on the farm, 2 strings.
looking at my graphs from a few days ago when there was reasonable sun, string 1 was getting to about 10.5 kw, but string 2 was reaching 11.0 kw.
Having said that my panels were installed in 2012, so by now there could be some low level shorting in some of the panels.
Interestingly string 1 seems to produce more power up until about 09:00, then string 2 is higher after that. (maybe some shading by trees)
I think there is variability in the panels, so they will never match...
ACarneiro
Active Member
I suspect a 5% variation is well within the acceptable limits, especially on a 10 year old system 
Just had our inverter converted from 8kw to 5kw (wrong one was delivered so installed with what was to hand). Cloudy day today and saw an instant doubling of output. Super result. The 8kw was fine on a sunny day, but on a dull day it really sucked, sometimes outputting only 30% of what solcast predicted. On sunny days solcast was generally within 10% of actual production.
Right size your inverter!
Right size your inverter!
Garry TheBiz
Member
Or lightly undersize it. That way it'll crop a little on the super sunny days, but start producing earlier and stop producing later in the day. It will also perform slightly better in the winter months.
Those who have set up solar, have you stayed on Octopus Go or is there something better to switch to? Can you use Go and get a FIT at the same time? (From googling it looks like you can’t)
Also are you charging your batteries fully from Go each night?
Also are you charging your batteries fully from Go each night?
PITA
Model 3 Performance
Our East / West Solar Array is 7.2 kWp
But the SolarEdge HDwave inverter is 5kW
Throughout the Summer I generally do not get 5kW clipping due to panel heat. Heat can knock 20% off the efficiency at times. Which is OK as I generally have more power than I can store or use on very hot days...
The only months where I may get clipping is March & April. The perfect conditions for bright sunshine and very cold days.
I've found the East / West array is perfect for our house because we get a wide spread of power throughout the day which is perfect when you work from home. Rather than a South facing array which is a later start, earlier finish and more likely to clip mid day...
SolarEdge HDwave Inverters allow for a 150% oversized array... again perfect.
Hopefully in the next 18 months I'm going to add another 4kWp East facing Array. With a 4 kW inverter, and two more Powerwalls (or a V2H capable car). Get more early morning sunshine to set us up for the Winter days.
Total of 11.2 kWp and 54 kWh storage is the plan.
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PITA
Model 3 Performance
Yes, I've stayed with Octopus Go. Currently on their 7.5p / 30p / 25p Standing Charge.
Don't have FIT... But do have SEG at 4p (not that I use it)
Charging batteries overnight all depends on the Sunshine during the previous day, and following days.
But during Winter, yes... the engine room is instructed to engage Warp Drive for battery charging.
Go works for me but it’s down to individual usage. I ‘m retired with no regular commute so can solar charge over a number days if necessary.
I use very little grid over summer and only off peak over winter.
I’ve been watching and reading this thread with interest for months now and think it is time for me to get some quotes for a PV and battery system.
Good thing is that I have a large absolutely south facing roof with zero obstructions such as trees. Plus an east/west facing double garage with a pitched roof.
Can anyone make recommendations for installers that cover south west Oxfordshire? Would be really appreciated.
Like the look of the GivEnergy system and any thoughts on that would be great. Tesla battery would also be good but with the current lead time…
Thanks in advance all.
Good thing is that I have a large absolutely south facing roof with zero obstructions such as trees. Plus an east/west facing double garage with a pitched roof.
Can anyone make recommendations for installers that cover south west Oxfordshire? Would be really appreciated.
Like the look of the GivEnergy system and any thoughts on that would be great. Tesla battery would also be good but with the current lead time…
Thanks in advance all.
PITA
Model 3 Performance
I used Stratford Energy Solutions in Warwickshire...
Expert Solar Panel Installation | Based In The UK | Stratford Energy
Stratford Energy are a trusted solar panel installation contractor specialising in solar pv systems, ev charging & energy storage.
www.stratfordenergy.co.uk
Awesome thank you. Will take a lookI used Stratford Energy Solutions in Warwickshire...
Expert Solar Panel Installation | Based In The UK | Stratford Energy
Stratford Energy are a trusted solar panel installation contractor specialising in solar pv systems, ev charging & energy storage.
I'm sorry if I'm missing the point here, but if you can get an Octopus deal that enables you to charge your car and solar battery for 7.5p kWh, why bother with solar panels, Why not just have a solar battery that will cover 24 hrs of usage in mid-winter (typically highest demand) and only pay 7.5p for all your electricity? As I say, I'm sure I'm missing something here. Sorry if this is a dim question!
The 7.5p kWh price will keep increasing. Any solar energy you create is 0.0p kWh, and if you install solar at the same time as a battery, you don’t pay VAT on the battery which you would do if you purchased it on its own.
But yes, battery only is worth considering.
Free is even better than 7.5p? Enough battery to last all day unsupported by panels will also require a pretty hefty investment. Interested in seeing the math if you can be bothered?
Definitely a use case there in the modern world tbh.
Really it’s a timing thing. Batteries Are only just becoming a viable consumer offering, but we’ve had consumer solar for over a decade including heavy government incentives at the start
I can imagine that will shift with batteries providing more options - including virtual power plant/net metering options. But at the moment solar is the ‘default’ and batteries are an add-on to that
And most people don’t have 7.5p off peak - we’re likely quite a small minority that allows octopus to play with data. Most are paying 30p and soon 52p per unit, and at that level the ‘free’ solar is valuable in itself, and batteries also useful to improve your % self consumption
I can imagine that will shift with batteries providing more options - including virtual power plant/net metering options. But at the moment solar is the ‘default’ and batteries are an add-on to that
And most people don’t have 7.5p off peak - we’re likely quite a small minority that allows octopus to play with data. Most are paying 30p and soon 52p per unit, and at that level the ‘free’ solar is valuable in itself, and batteries also useful to improve your % self consumption
PITA
Model 3 Performance
That's exactly how I started my Tesla journey.
I bought a Single Powerwall 2 with Gateway 2... and that was it.
I downloaded cheap electric overnight to use during the day, and give me blackout backup.
After about 8 months, I then started expanding the system with a Solar Array, another Powerwall, Water Heater and EV Charger.
I then converted to 3 Phase power, smart meters, added another 22kW ev Charger and bought a Tesla Model 3 Performance.
Once that lot was established I then bought a Heat Pump, an Inverter cooking hob, and went 100% electric
RedMod3
Member
Just been modelling my current system of 2PW and 5.5kW gross against 3PW and 8.5kW gross, with current and expected rate changes. It's kind of confirmed my decisions. At the start of the year, I had 0PWs and 4kW gross. Prices have changed business case.
Now for expected rates when I renew in March next year.
| Off-Peak | 5.000 | |||
| Peak | 15.590 | |||
| PWs | 0kW | 4kW | 5.5kW | 8.5kW |
| 0 | £1,668 | £1,465 | £957 | |
| 1 | £1,216 | £1,022 | £759 | |
| 2 | £911 | £810 | £600 | |
| 3 | £751 | £676 | £499 |
Now for expected rates when I renew in March next year.
| Off-Peak | 10.000 | |||
| Peak | 60.000 | |||
| PWs | 0kW | 4kW | 5.5kW | 8.5kW |
| 0 | £5,930 | £5,148 | £3,193 | |
| 1 | £3,795 | £3,062 | £2,260 | |
| 2 | £2,333 | £2,055 | £1,507 | |
| 3 | £1,600 | £1,428 | £1,029 |
ACarneiro
Active Member
Why do you expect off peak power to increase so modestly?
I hope it does, but it’s by no means a certainty…
I hope it does, but it’s by no means a certainty…
