Anyone got solar panels and Tesla Powerwall ?

[Silver-Fox]

It is because the home solar system feeds power into the grid so it has to match it.
Your van power stands alone and does not have to match anything.
You can have an ‘island’ switch for your home which isolates it from the grid properly at which point it no longer needs to match, but the inverter will need to have a mechanism for setting its own AC phase without an input in that case.

Thank you.

That makes sense

I would want an isolating switch.
I had one at the last house to run a small generator to keep the boiler and kitchen going.

 

[Silver-Fox]

For safety reasons most inverters need there to be mains power to trigger them to run.

Tesla and Victron don’t as they isolate the incoming power feed as soon as it loses power.

Thanks

 

[mikesue32]

Definitel;y worht researching all systems. Some allow you to recharge from poff peak as well as solar, others don't

 

[pau1phi11ips]

I’m sure there are more qualified out there that would know.

But why could you not just have an isolating switch to stop feedback.

Most of the solar inverters will be grid-tied. They need to have the mains input so they can sync up 50 or 60Hz waveform before they start outputting power.

For off grid use, you need to have a automatic transfer switch to disconnect your house from the mains and have an invertor that can generate the 230V AC on it's own for the solar inverters to sync to.

In a nutshell, it's do-able but gets complicated.

 

[EuroTrotters]

We had a 20 x 360-watt solar pv array fitted thirteen days ago, together with 13kWh (2 x 6.5) of Growatt lithium storage and a smart hybrid inverter.

Since then we've effectively been self-sufficient for electric and free of the grid, even though we've had to contend with storms Eunice and Franklin, together with extensive cloud and rain for the last four days here in the west.

Obviously cost a lot less than the Tesla Powerwall - the batteries were £4,737 inc 5% vat for the two.

However, it's early days and we've no intention of disconnecting from the grid. Nonetheless, we've been impressed how effective the set up has been so far, especially given the time of year. The batteries are warranted for 10 years, and I think it's 25 for the panels.

From my perspective, the batteries are a game changer.

View attachment 591370View attachment 591371

That looks a good setup. Wouldn’t mind something like that

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[Tombola]

Sorry to rake up an old thread but seems I didnt see any notifications of replies last year

I see Tesla are now looking to potential energy supply in the UK,
Im again thinking of going down the solar/powerwall route even though the house isnt best faced Im told better panels and some on each side of the house etc can help this.

Does anyone have different batteries that they would say are a good alternative, and Ejaydee did your install get done, how was it

 

[Howard B]

Sorry to rake up an old thread but seems I didnt see any notifications of replies last year

I see Tesla are now looking to potential energy supply in the UK,
Im again thinking of going down the solar/powerwall route even though the house isnt best faced Im told better panels and some on each side of the house etc can help this.

Does anyone have different batteries that they would say are a good alternative, and Ejaydee did your install get done, how was it

I have Givenergy batteries which I am happy with. Have two 8.25kWh batteroes, , but if I were updating Id go with this https://www.givenergy.co.uk/products#giv-all-in-one

 

[Swamp]

I’ve got 12 x 390w panels and two Tesla Powerwalls. The solar panels and one Powerwall were fitted in the Autumn of 2021 and I added the second in March this year.

I love the system. The control app is very smart. From mid March until mid October I don‘t use any grid power at all and export surplus power at 15p/kWh. During winter I have the system set to automatically top up the batteries as required overnight from the grid. I’m on an economy 7 tariff from Octopus and only pay 16p/kWh to charge. The system learns household use and guesses solar input at any given time of year to only top up as required leaving space for any solar generated during sunny winter days. I never use peak rate power at any time in the year.

I’ve switched to fully electric cooking and heat water using an immersion heater during the summer. In winter I switch to gas water heating.

It also provides instant protection in the event of power cuts - I am on a somewhat dodgy supply from National Grid and usually get half a dozen noticeable power cuts each year. I simply don’t notice them now - I only get to see them logged in the Tesla App. As a final trick, it has a “storm watch” facility which means that if a serious storm is forecast for the area which could knock out grid supply it will switch to charging to 100% in advance to give maximum power cut protection. This worked brilliantly for storm “Arwen” which hit just after the system was installed. Power did get cut off, batteries were at 100% - no problems!

An expensive system but it just works really well

 

[Tombola]

I’ve got 12 x 390w panels and two Tesla Powerwalls. The solar panels and one Powerwall were fitted in the Autumn of 2021 and I added the second in March this year.

I love the system. The control app is very smart. From mid March until mid October I don‘t use any grid power at all and export surplus power at 15p/kWh. During winter I have the system set to automatically top up the batteries as required overnight from the grid. I’m on an economy 7 tariff from Octopus and only pay 16p/kWh to charge. The system learns household use and guesses solar input at any given time of year to only top up as required leaving space for any solar generated during sunny winter days. I never use peak rate power at any time in the year.

I’ve switched to fully electric cooking and heat water using an immersion heater during the summer. In winter I switch to gas water heating.

It also provides instant protection in the event of power cuts - I am on a somewhat dodgy supply from National Grid and usually get half a dozen noticeable power cuts each year. I simply don’t notice them now - I only get to see them logged in the Tesla App. As a final trick, it has a “storm watch” facility which means that if a serious storm is forecast for the area which could knock out grid supply it will switch to charging to 100% in advance to give maximum power cut protection. This worked brilliantly for storm “Arwen” which hit just after the system was installed. Power did get cut off, batteries were at 100% - no problems!

An expensive system but it just works really well

brilliant info thanks for taking time

 

[MisterB]

I've got 14.3kw and will be adding another 14.3kw in September. Just about to change my inverter
Batteries are self built from fogstar. A massive saving on a commercial system and it really is mainly plug and play

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[Ejaydee]

Sorry to rake up an old thread but seems I didnt see any notifications of replies last year

I see Tesla are now looking to potential energy supply in the UK,
Im again thinking of going down the solar/powerwall route even though the house isnt best faced Im told better panels and some on each side of the house etc can help this.

Does anyone have different batteries that they would say are a good alternative, and Ejaydee did your install get done, how was it

Hi yes, powerwall was installed in mid February. The install went very well and the system has been brilliant. I have just looked at the Tesla App display, and we are on a ‘saving’ of £847 to date. At this rate, the battery will be paid for in about 5years, possibly less. That is in an all electric house with ASHP for heating and hot water, and two EVs. The EVs at the moment are charged from solar and Powerwall as we have not needed to do any long journeys, so it has cost us nothing to charge them (other than the investment costs). Most days at this time of year our only electricity cost has been the daily standing charge. Hope that’s helpful, PM me if you want any more info.

 

[andykim]

Do your batteries cut in automatically and provide backup power in the event of a power cut?

I don't think they do unless you have a completely separate electrical set up from the mains supply,this I think is a safety issue to stop engineers being electrocuted from an outside source ie solar feed and batteries.

 

[Swamp]

I don't think they do unless you have a completely separate electrical set up from the mains supply,this I think is a safety issue to stop engineers being electrocuted from an outside source ie solar feed and batteries.

The Tesla system does provide automatic (and effectively uninterupted) power in the event of a power cut. It has a central control box, the gateway, which handles all the smart stuff like stopping export in the event of a power cut to protect engineers who may be working on repairing the grid. I‘m on a pretty dodgy grid connection and used to get numerous power outages. I no longer notice them at all.

 

[ManTheVan]

I’ve got 12 x 390w panels and two Tesla Powerwalls. The solar panels and one Powerwall were fitted in the Autumn of 2021 and I added the second in March this year.

I love the system. The control app is very smart. From mid March until mid October I don‘t use any grid power at all and export surplus power at 15p/kWh. During winter I have the system set to automatically top up the batteries as required overnight from the grid. I’m on an economy 7 tariff from Octopus and only pay 16p/kWh to charge. The system learns household use and guesses solar input at any given time of year to only top up as required leaving space for any solar generated during sunny winter days. I never use peak rate power at any time in the year.

I’ve switched to fully electric cooking and heat water using an immersion heater during the summer. In winter I switch to gas water heating.

It also provides instant protection in the event of power cuts - I am on a somewhat dodgy supply from National Grid and usually get half a dozen noticeable power cuts each year. I simply don’t notice them now - I only get to see them logged in the Tesla App. As a final trick, it has a “storm watch” facility which means that if a serious storm is forecast for the area which could knock out grid supply it will switch to charging to 100% in advance to give maximum power cut protection. This worked brilliantly for storm “Arwen” which hit just after the system was installed. Power did get cut off, batteries were at 100% - no problems!

An expensive system but it just works really well

We have a similar system (5kW of PV and a Powerwall). The panels were fitted last November and we have just gone over 3mWh produced since then.

The Powerwall was delayed so didn’t go in until April this year, but has been great too.

I’d be very interested to see your settings in the Tesla app. We are on Intelligent Octopus which gives us overnight charging for the EV (and any other consumption) at 7.5p/unit. When it comes to winter, I’d like to set the app to charge the Powerwall overnight too, when we might not generate much if it’s dull. I’ve set up the tariff in the app and it’s all saved.

I tried setting it to Time Based control last night, and saw, in the early hours, that it had put the Powerwall in standby at 82% and was taking power from the grid to cover the house’s background use of 0.2kW. I thought it might have been charging the Powerwall instead?

Any advice on settings to achieve winter overnight charging would be really helpful.

 

[Swamp]

We have a similar system (5kW of PV and a Powerwall). The panels were fitted last November and we have just gone over 3mWh produced since then.

The Powerwall was delayed so didn’t go in until April this year, but has been great too.

I’d be very interested to see your settings in the Tesla app. We are on Intelligent Octopus which gives us overnight charging for the EV (and any other consumption) at 7.5p/unit. When it comes to winter, I’d like to set the app to charge the Powerwall overnight too, when we might not generate much if it’s dull. I’ve set up the tariff in the app and it’s all saved.

I tried setting it to Time Based control last night, and saw, in the early hours, that it had put the Powerwall in standby at 82% and was taking power from the grid to cover the house’s background use of 0.2kW. I thought it might have been charging the Powerwall instead?

Any advice on settings to achieve winter overnight charging would be really helpful.

During the summer months when there’s plenty of solar and no risk of fully discharging the batteries I run the Powerwall in “Self Powered” mode. This will never take power from the grid if there is power available in the batteries.

In the Autumn, as solar levels drop, I switch over to the “Time based” setting. I have an economy 7 type tariff from Octopus (I don’t yet have an electric car so don’t qualify for their Intelligent Octopus tariff). I get cheap rate from 00:30 to 7:30 and during this time the Powerwall will draw from the grid to cover background house use and, if it estimates that it is needed, will top up the battery to a level which should cover the following day’s use leaving a bit of spare capacity for any solar that is available. The system learns your household use and also the solar it typically gets at any time of year so its estimates improve with time.

Overall it seems to work well.

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[Tombola]

I know this is a "piece of string" question, my house point just a little south than east (east south east)
asking I was told as panels can be fitted on the front and back to catch it up to midday and after midday then there is negligable loss.

I always thought if it wasnt south facing its not worth it?

can anyone expand ?

 

[MisterB]

I know this is a "piece of string" question, my house point just a little south than east (east south east)
asking I was told as panels can be fitted on the front and back to catch it up to midday and after midday then there is negligable loss.

I always thought if it wasnt south facing its not worth it?

can anyone expand ?

The old mantra was to fit them to south facing roofs or as close to it. That was based on a max production of 4kw (actually around 3.6). As it's ok with approval to fit a larger array (panels are well in excess of 250w now) then trying to catch the sun at different times of the day is becoming more recognised as a way of maximising solar energy. Plus of course not many people have a single roof capable of taking up to 8kw if panels.

Even when the sun isn't directly on our panels we can still pick up 0.5kw an hour easily. However whether that translates into it being cost effective to fit 'non south' is really for you to consider.

You might be better off rather than spending the money on solar panels non south facing and spend it on battery storage instead. There needs to be a balance between what you would use at the time of production and what you could use if stored. I get fed up of watching how much power I send back to the grid through excess solar generated power, only to have to buy it back again! So for me increased battery storage provides a more economical outcome. What we should also consider are garden or garden fence or wall mounted panels ....

 

[DavidG58]

Ours have been fitted 1/3 facing east 2/3 south, in summer we generate well over 1Kw soon after sunrise

 

[Coolcats]

Do your batteries cut in automatically and provide backup power in the event of a power cut?

Many or most systems don’t as you would be powering the network and any linesman would be zapped. What you can have are eps (emergency power sockets) that can be used in the event of a power fail.

 

[MisterB]

Many or most systems don’t as you would be powering the network and any linesman would be zapped. What you can have are eps (emergency power sockets) that can be used in the event of a power fail.

Thats exactly what we have, we have our inverter in an outside utility room which also houses our larger fridge and freezer. if power fails then it feeds just those two appliance, basically using a DPDT relay. Its a lot easier than it sounds to set up.

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[ManTheVan]

During the summer months when there’s plenty of solar and no risk of fully discharging the batteries I run the Powerwall in “Self Powered” mode. This will never take power from the grid if there is power available in the batteries.

In the Autumn, as solar levels drop, I switch over to the “Time based” setting. I have an economy 7 type tariff from Octopus (I don’t yet have an electric car so don’t qualify for their Intelligent Octopus tariff). I get cheap rate from 00:30 to 7:30 and during this time the Powerwall will draw from the grid to cover background house use and, if it estimates that it is needed, will top up the battery to a level which should cover the following day’s use leaving a bit of spare capacity for any solar that is available. The system learns your household use and also the solar it typically gets at any time of year so its estimates improve with time.

Overall it seems to work well.

Really helpful Swamp, much appreciated.

We’re in self-powered mode now and have been since installing, but your post has explained why the system wasn’t charging the Powerwall in the early hours.

It would be brilliant if there was some automatic setting to tell the Powerwall not to use its energy to charge the EV, but I think I’ll just have to manage this manually.

 

[ManTheVan]

I know this is a "piece of string" question, my house point just a little south than east (east south east)
asking I was told as panels can be fitted on the front and back to catch it up to midday and after midday then there is negligable loss.

I always thought if it wasnt south facing its not worth it?

can anyone expand ?

That used to be the case, but today’s efficient panels will generate well when facing bright conditions (ideally South, then East/West).

We have 7 x 390W facing directly East and 6 x facing South. The system generates masses of power from sunrise and through until late afternoon/early evening (depending on time of year and cloud cover). But for the trees on the W side of the house we would have fitted on the W side too.

 

[ManTheVan]

BTW, for anyone that’s interested, we applied for SEG from Scottish Power who appear to be totally incapable of providing any sort of service. They rejected our application, saying we needed a smart meter that could measure export, despite me having to provide photographic evidence of the meter showing an export reading, as part of the application.

The only way to communicate with the SEG department is by a single email address. However, the SEG department do not and have never replied to any communication sent. The customer services team cannot help with SEG and just refer you to the SEG email. The CEO doesn’t reply to emails either.

They are a complete disaster to deal with so I’ll find another supplier for SEG that values customers. Any suggestions?

 

[Ejaydee]

Been travelling back home from the Highlands End Fun Meet, in 'interesting' weather to west Cornwall.

ManTheVan Like yourself and Swamp, we have an Economy 7 type tariff but it is with EDF, not Octopus. I have set the Tesla app onto 'time based charging', really just to test the system while we are making lots of solar.

I have noticed that the battery only charges to 70% to 80% if the weather forecast for the next day has any sun expected in the forecast, but it does charge to the high 90's % if rain and overcast conditions are forecast. The guys that installed the battery said the app was relatively smart, but to be honest I took that with a pinch of salt, but I am beginning to wonder if that is correct or whether it has been coincidence.

EDIT. Ah ha, I have just reread the thread and notice that Swamp has said as much in post #75

We have two EVs, so are also experimenting with charging them up from the solar/powerwall and also from cheap overnight rate. and so far it has worked very well. Obviously, it will not be as easy during the winter months, but if we can get one off the cars and the power wall charged during cheap rate, that will be really good.

 

[Swamp]

BTW, for anyone that’s interested, we applied for SEG from Scottish Power who appear to be totally incapable of providing any sort of service. They rejected our application, saying we needed a smart meter that could measure export, despite me having to provide photographic evidence of the meter showing an export reading, as part of the application.

The only way to communicate with the SEG department is by a single email address. However, the SEG department do not and have never replied to any communication sent. The customer services team cannot help with SEG and just refer you to the SEG email. The CEO doesn’t reply to emails either.

They are a complete disaster to deal with so I’ll find another supplier for SEG that values customers. Any suggestions?

I’ve found Octopus to be pretty good

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[MisterB]

i visited the solar show last year at the NEC, it was on at the same time as the motorhome show, so i took advantage of a wander around.

i spoke to several different providers of storage batteries (power wall is a trade name) and inverters and they were all talking about the new 'weather forecast app' that had been developed and applied to lots of inverters - supplying the inverter with times and scheduling of when to charge/discharge etc. I think they actually 'just' use the local weather forecast where ever you are, but its still a clever and smart application

my issue was and still is, unless you have sufficient storage facility (and how big is sufficient) then you will lose harvested power to the grid at some point.

there is a 'spot' where you use most of it and the rest goes into your storage and very little gets fed back. but that would entail having massive storage facilities and it just wouldnt be cost effective. No point spending 5k on a battery (as an example only) to save £5 a week! So you need to find a happy medium of cost versus benefit and each scenario/location will be different.

for me at the moment, its having 4kw of solar, 28.6kw of storage and an inverter that can draw 5kw per hour from the grid in winter during octopus go periods (4 hours). If i increased my battery storage, i would have to massively increase my solar or increase the capacity of my inverter to charge the batteries but it would potentially take around 10 years to recoup the cost!

 

[Bessy765]

We have. A 16 panel array on our garage roof which faces just east of south inclined at 10 degrees. (Would have had it at 30 degrees but our Victor Meldew got a couple of neighbours to object and was a councillor. This is throttle to 4.6 kw as the max allowed. But the just under 6 kw. Array was to help in the lower sun and shorter daylight hours. This is linked to a 3.7 kw solax inverter (this should have been 5 but apparently this was all that was available.) This charges 2 x 5.8 Triple Power batteries. (These should have been 6.5 growatt but again this was all available) complete and utter bunch of cowboys but legal states I cannot mention them at this moment in time. Installation finish October 2022 but still waiting for MCS certificate. When the rep first came during the conversation he gave me a leaflet from HIES it has a picture of George Clark the architect on the front and promises a trouble free installation backed by them. having not discovered the difference in the batteries or inverter as was not too well at time of installation and they refused payment by credit card found the discrepancies after. They had left. Dos contacted HEIS no reply for 5 weeks and then only by chasing them on the phone which with COPD is hard for me. I was told as I had paid the there was nothing they could do (fat lot of good and at odds with their pamphlet. Having still not recived the MGS or warranty documents contacted HEIS as the boss of the installing company said I had caused him a lot of trouble and not to phone him again. HEIS said to contact NAPIT as they dont deal with the certificate or documents so what is the point of them?? So contact NAPITT they asked for screen shots of any documents I had and wouid investigate, haveing not heard from thhe for some time e mailed them again, was told my certificate is being processed in a system but they do not have access as this is done by another department. So ten oaths later stilll not resolved. I have tried to e mail George Clark to see if he is aware of just what he is endorsing as having his name promoting a company was reassurin. (Not) I also have a 1.12 kw system on our house roof that faces due south which performers very well this was one of the first installations in our area about 12 years or so ago. We still benefit from a 68p per unit for all that we generate on this stand alone system wether we use it or not so it seems it would outway transferring to the SEG tarriff which only pays you for any excess generated it returns around £650 per year. The garage roof system has generated 2.63 kw from Oct 2022 until present day and we have spent not counting standing charges 27p in June and 13 p to date for July. This is the result of having a 3 kw inverter and occasionally going over its output of 3700w
sorry such a long post currently in Turkey having had the last of my teeth removed and 8 implants. So have to stay indoors today because of the heat and sunshine 45c at the moment.

 

[amyjones329]

I find that amazing! I have one fridge , & 2 new small top rated freezers , The lights are all led's & even if on 24hrs/day consume only 0,75kw. Apart froma couple of lap tops there is no other electric consumption & we cannot get it below 4 kw/day?

=

I've got 14.3kw and will be adding another 14.3kw in September. Just about to change my inverter
Batteries are self built from fogstar. A massive saving on a commercial system and it really is mainly plug and play

We have a solar panel setup that takes us down to 2 kw/day but I can't seem to get it lower? Any suggestions would be much appreciated! Thanks in advance!

 

[MisterB]

=

We have a solar panel setup that takes us down to 2 kw/day but I can't seem to get it lower? Any suggestions would be much appreciated! Thanks in advance!

2kw from the grid is pretty good to be fair, is that an average over a 12m period ?

Do you have storage batteries?.

 

[amyjones329]

2kw from the grid is pretty good to be fair, is that an average over a 12m period ?

Do you have storage batteries?.

Yes , I have four 6V batteries wired in series for a total of 24V.

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