Solar Panels UK - is it worth it?

[yessuz]

OK, this is learning stage...

Basically, today I got my Solar system comissioned. It consists of:

• 20 x 415 w panels (8.3 kwp) - 10 east & 10 west
• Growatt SPH6000 inverter
• 3 x Pylon US3000C batteries (total 10.5 kwh)

System in the Shine app showed that the PV was generating (rain and miserable, so very little, just 0.3 kw (maxed up to 0.73 kw for brief time). all that power was consumed by house. Battery sitting at 50%.
So all looked good.

But now, in the evening, I am drawing all my power from the grid. battery is still sitting at 50%.

Is there maybe some sitting which I need to look at or something, in order to enable the use of the battery? or I need to wait for some magic from Growatt side? as mentioned - system comissioned today, late afternoon :/

 

[Pete UK]

Not a lot of power though - worst day for solar in the midlands so far this summer!

Yeah today was really poor. 10.6kW generated for me. Powered the house and added 1% to the batteries.
Wife decided to charge the car this evening/overnight. So I reckon we’ll be down to 10% by sun up. Still no grid use yet but tomorrow…?

 

[phil4]

I'v

now the question is this:
who has Growatt inverter and what is the best settings for it?

My aim is everyone's I believe, priority being:
1) Cover whole house load by Solar.
2) If Solar is not enough - use the battery (during peak time).
3) if there is specific time of day (23:30 - 5:30 when I have the cheapest power and no solar and I charge the car: charge battery.

any advice is appreciated

On my system I can't set a limit for charging, but can tell it what to aim for, ie. what level to aim for with the battery.
My aim is pretty much as yours. Or rather its:
1) Don't run out of battery
2) Don't charge the battery to 100%.

So to that aim I've been playing around with formulas using forecasts to decide the target charge. I started with a notional aim of wanting the batteries at 80% on a poor day. less than that if it's going to be really sunny, more than that if it's 2 days of night.

I've ended up with this in Home Assistant:
{{90-(((((states('sensor.forecast_today') | float)+(states('sensor.forecast_tomorrow') | float))/6)/0.27) | int) }}

90 because we shift the scale, so if 2 days of night, we "add" above the target 80. So we add today and tomorrow (or tomorrow and D3 for tomorrow's plan), then divide by 6... this reduces the impact of the solar on target charge, lower number = bigger impact... this started as /2 to average the two values, but I needed to reduce it further. 0.27 turns the kWh into a percentage.

The thinking is on a day where the sun is blazing for 2 clear days, it'll drop the battery level down to below 50% each day, and on miserable days like yesterday it'll push it up to 70-80%.

I've yet to see how this pans out but modelling looks ok. I expect I'll just end up tweaking the scaling factor (6 on the above), to find a sweet spot where the prediction meets what's really needed. Part of the fun is the prediction isn't always right (actually, usually isn't).

 

[Mrklaw]

OK, this is learning stage...

Basically, today I got my Solar system comissioned. It consists of:

• 20 x 415 w panels (8.3 kwp) - 10 east & 10 west
• Growatt SPH6000 inverter
• 3 x Pylon US3000C batteries (total 10.5 kwh)

System in the Shine app showed that the PV was generating (rain and miserable, so very little, just 0.3 kw (maxed up to 0.73 kw for brief time). all that power was consumed by house. Battery sitting at 50%.
So all looked good.

But now, in the evening, I am drawing all my power from the grid. battery is still sitting at 50%.

Is there maybe some sitting which I need to look at or something, in order to enable the use of the battery? or I need to wait for some magic from Growatt side? as mentioned - system comissioned today, late afternoon :/

for givenergy I have the following controls which may be different but perhaps only slightly

- standard mode during the day uses solar to charge the battery if there is excess and uses the battery during the day to top up house load. All good
- you have a minimum discharge level to protect the battery - mine is set by default to 4% as its LFP. If this is set to 50% it won’t go below that. Worth checking.
- for offpeak charging I would prefer not to drain the battery as it’ll barely touch the sides of the car. So for that time period I have the battery set to charge. But on givenergy its a bit odd. You set it to charge to a %. if its higher than that % (common in summer at the start of off peak) it’ll still allow drain for covering house loads until it gets below that, then it starts to charge. Eg if I have it set to 25% during summer it’ll almost never get below that just from house use, so its more a safety net. If I plug the car in it’ll quickly hit that and then use grid to keep at that level and prevent further discharging. So when the morning comes around with peak rate, I’ll still have that 25% to get me to when solar starts coming in. That % can be adjusted in the app

 

[Pink Duck]

Just 17.4 kWh for me yesterday too, not enough to fill a single Powerwall 2 for the first time since install 3 weeks ago.

 

[yessuz]

so I am trying to get to the bottom of the issues.

currently the battery is not being discharged or charged from PV. it looks like battery is not being used to anything other than just charging it during the specific time I set. but once it is charged - it is not discharged.
Also, on the Growatt dashboard it does not show any load from grid (i.e. yesterday I see that solar generates 0.7 kw, put kettle and washing machine on, it shows nothing
Also it shows that house consumes all power what solar generates, which cannot be true as it shows that house consumes 4 kw while actual load in the house is at region of 200w.

some setting somewhere is wrong.

 

[Avendit]

so I am trying to get to the bottom of the issues.

currently the battery is not being discharged or charged from PV. it looks like battery is not being used to anything other than just charging it during the specific time I set. but once it is charged - it is not discharged.
Also, on the Growatt dashboard it does not show any load from grid (i.e. yesterday I see that solar generates 0.7 kw, put kettle and washing machine on, it shows nothing
Also it shows that house consumes all power what solar generates, which cannot be true as it shows that house consumes 4 kw while actual load in the house is at region of 200w.

some setting somewhere is wrong.

Have they finished commissioning it all? Sounds like some sensors (probably master CT clamp) aren't reading right, but that's a really basic check.

 

[yessuz]

Yeah got the message drom installer. Growatt and installer identified issie and will sort on monday.. fingers crossed

 

[Mrklaw]

away from home at the moment but just checked energy dashboard. Yesterday we generated 6.6kwh! only got the battery up from 50% to 80% before the solar stopped. Still managed to get to the start of this morning with 66% thanks to no dishwasher and nothing during the evening.

Oddly I have quite high home load showing - 700w in little bursts during today but should be nobody at home..wish I’d set up remote access for home assistant now, or a camera in the living room (at least when I’m out)

whats all this about? nobody in the house since yesterday afternoon..

 

[Avendit]

Fridge?

 

[Mrklaw]

Fridge?

Scarily that was my first thought after dialling in and checking the sockets I could - till out leaving the amp and tv on (although they power off)

The on/off might suggest compressor cycling?

But why 1pm today? Nobody has been in the house since yesterday. Maybe left the fridge/freezer door ajar but only now causing an issue?

Nobody back in the house until Wednesday at the earliest.. might see if I can drop into the kitchen Alexa and hear the fridge alarm

 

[Pete UK]

away from home at the moment but just checked energy dashboard. Yesterday we generated 6.6kwh! only got the battery up from 50% to 80% before the solar stopped. Still managed to get to the start of this morning with 66% thanks to no dishwasher and nothing during the evening.

Oddly I have quite high home load showing - 700w in little bursts during today but should be nobody at home..wish I’d set up remote access for home assistant now, or a camera in the living room (at least when I’m out)

whats all this about? nobody in the house since yesterday afternoon..

View attachment 956505

If you look closely you might be able to see that these spikes coincide with an increase in PV generation and/or grid export. It could be something to do with a bit of lag when things are changing over which is seen as “house load”.

Or are you talking about the approx 4/500w increase continuously from about 13:30?

I’m finding with multiple batteries and inverters, I’m seeing the batteries being charged shown as “house load”. To be honest some of the data isn’t always showing properly in the app/portal in “away” mode. Like the generation etc. The only thing that I’m 100% confident with is data from the “inverter” tabs eg the PV/meter data etc. Which is accurate.

Looks like being in the Beta testing has 99% fixed the cross charging problem as well. Which is a relief. Just need to wait for the physical EMS to be completed and become available now. Maybe they are waiting for more data/ testing time before they release it?

 

[DaveNN]

Scarily that was my first thought after dialling in and checking the sockets I could - till out leaving the amp and tv on (although they power off)

The on/off might suggest compressor cycling?

But why 1pm today? Nobody has been in the house since yesterday. Maybe left the fridge/freezer door ajar but only now causing an issue?

Nobody back in the house until Wednesday at the earliest.. might see if I can drop into the kitchen Alexa and hear the fridge alarm

Fridges, freezers etc will fire up the compressors occasionally.
Do you have external lights?

 

[DaveNN]

With the wallbox scheduled charge failing, with the car at only 20% (I've now binned the app etc) only 1kwhr of pv being generated , I was resigned to pay 30ppkwhr for the car charging.
I replug in an IO have given me 7.05ppkwhr until 4am tomorrow.

Yay.

 

[nufan]

@PITA - I know it was a couple of years back now - but what did your Haori setup cost all told? External unit + four rooms was it & quiet condensation pump?

Just wondering what the broad costs are.

 

[PITA]

@PITA - I know it was a couple of years back now - but what did your Haori setup cost all told? External unit + four rooms was it & quiet condensation pump?

Just wondering what the broad costs are.

At the time it cost me £6500 all in.

But every home is different because of the pipework routing.

We also had Aspen Peristaltic Pumps, not gravity draining. The Peristaltic Pumps allow us to position the internal wall units 'exactly' where we wanted them, rather than external wall only.

The Pumps sit in the loft well away from the bedrooms are are completely silent in living spaces. You can only hear them in the loft (just make sure they don't screw them to rafters or trusses, because the sound will resonate through the house). Each pump needs to have a small section of pre-lubricated pipe replaced every year as maintenance. Costs about £9 per part, and involves three screws. Really easy.

The outside compressor is 3 meters from our neighbour Boundary, and cannot hear it over ambient noise. But I do clean it myself every year to keep it in good condition.

The internal wall units are 'hotel' quiet. Just a whisper of air and easily don't impede sleep.

I went with Toshiba Haori wall units because they're WiFi enabled for App Control and remote access, scheduling, and connects to Alexa for voice control. Yes, you can ask Alexa to turn on Bedroom Air Conditioning.

Also have Plasma ion air filtering to capture particles as air passes through it.

Comes with infrared hand controller which is back-lit, for Guest rooms, or kids who don't have access to the App.

 

[Mrklaw]

Think maybe a power cut briefly whihc reset all the hue lights to on and set the towel rails to on (I’ll have to check the Shelly defaults when I get home). Still seems a bit high but the up/down is something I’ve seen before with the towel rails likely temperature cut off or something

Managed to see that via HomeKit that if exposed from home assistant and then turned them off. Seems better now but very odd - we rarely get power cuts

 

[PITA]

Something else worth considering with Air Conditioning at home... your large glass areas (like patio doors) are vulnerable for stress cracking / smashing.

Look at the screenshot below of our house last Summer. Outside was 40 Degrees... inside was 22 Degrees (which sounds hot) but that's a 18 degree drop from outside.

This temperature difference can Warp door frames bending the glass until it breaks. Toughened glass just shatters.

All our Windows and Doors are fitted with 6mm laminate double glazing (like hotels), which prevents this as the glass is MUCH stronger.

... and I know of this happening to people on here with Air Conditioning at home.

 

[nufan]

Many thanks @PITA - useful information there. I’ll mentally peg it ant £8-10k for planning purposes. Especially interested in the glass stress element as I want to replace the patio door arrangement sooner or later too with bifolds.

 

[PITA]

Many thanks @PITA - useful information there. I’ll mentally peg it ant £8-10k for planning purposes. Especially interested in the glass stress element as I want to replace the patio door arrangement sooner or later too with bifolds.

We went with PAS24 Security (Secure by Design) patio doors which included heavier frames, deadbolts, secure locks & hooks, plus 6mm laminate glass.

If you want to know the difference between standard glass, toughened glass, and laminate glass... watch the test below