Solar Panels UK - is it worth it?

[RichardTheKing]

With a single Powerwall, if you wait until there is no solar power (if you have solar panels), switch on a kettle and oven, or plug your car in at full rate.
if you PW is capped it will discharge at 3.6 or 5 if it isn’t and the rest will come from the grid. You’ll see that happening in the Tesla app

On the Powerwall specs it is written 5 kWh max discharge, then how could it be possible to be cap at 3.6? without anything (solar or panel- do not have but on order) I have switch on hobs/oven/and ev car and my Smart meter was at 16kWh

 

[scdoubleu]

When restricted to 3.68 kVA, the Powerwall's inverter will supply (or charge) up to that and no more. Anything over that will come from solar and/or grid. The restriction is something imposed by the DNO as a condition of connecting the PW to the grid where the local cabling/substation is under par.

 

[RedMod3]

That's normal behaviour. The option for Time Based Control will appear in a few days.

Yes, it has now appeared, but it will not let me save the rates. The good news is today that after my manual top-up between 00:30 and 04:30, I had just sufficient stored charge to see me through until the solar cut in, so I have only used power at 5p kWh since 00:30. And I have not exported anything to the grid FOC

 

[RedMod3]

On the Powerwall specs it is written 5 kWh max discharge, then how could it be possible to be cap at 3.6? without anything (solar or panel- do not have but on order) I have switch on hobs/oven/and ev car and my Smart meter was at 16kWh

The installer sets the cap and whether it will export to the grid when they commissioned the system. I watched my installer go through the options when he commissioned mine this week.

 

[Lx2m3]

Finally got to a proposed install date \o/ yay! In June waaaaaa.

I too am waiting patiently (not), didn’t get a proposed date yet, but a likely installation time frame!
PV installed in early May, Powerwall due in June.

 

[Dilly]

Yes, it has now appeared, but it will not let me save the rates. The good news is today that after my manual top-up between 00:30 and 04:30, I had just sufficient stored charge to see me through until the solar cut in, so I have only used power at 5p kWh since 00:30. And I have not exported anything to the grid FOC

Saving the rates was a faff. I tried changing what was there and it wouldn’t save. Start afresh and it should work. Use peak and super off-peak rather than off-peak. I can’t remember why but it works better for some reason. I set my sell (export) rates to zero. I found that any other amount caused my Powerwall to export to export to the grid when it had no business doing so!

 

[Mrklaw]

Saving the rates was a faff. I tried changing what was there and it wouldn’t save. Start afresh and it should work. Use peak and super off-peak rather than off-peak. I can’t remember why but it works better for some reason. I set my sell (export) rates to zero. I found that any other amount caused my Powerwall to export to export to the grid when it had no business doing so!

US focused software again? I think US tends to have ‘shoulder’ rates so peak/off peak/super off peak.

Still seems odd to me that there isn’t a mode that simply lets you set a ‘get to x% by the time my peak time starts’ so you can adjust based on preference rather than letting the AI guess - and charge from solar when possible.

The focus on self consumption over all else, or off peak only seems odd

 

[Dilly]

US focused software again? I think US tends to have ‘shoulder’ rates so peak/off peak/super off peak.

Still seems odd to me that there isn’t a mode that simply lets you set a ‘get to x% by the time my peak time starts’ so you can adjust based on preference rather than letting the AI guess - and charge from solar when possible.

The focus on self consumption over all else, or off peak only seems odd

We’ve been gnawing over that same lack of control for charging cars too. The Tesla focus seems enshrined in AI rather than simple common sense!

 

[RichardTheKing]

The installer sets the cap and whether it will export to the grid when they commissioned the system. I watched my installer go through the options when he commissioned mine this week.

I am going to prepared few French bottle of wine for the installer for not triggering that

 

[RedMod3]

Saving the rates was a faff. I tried changing what was there and it wouldn’t save. Start afresh and it should work. Use peak and super off-peak rather than off-peak. I can’t remember why but it works better for some reason. I set my sell (export) rates to zero. I found that any other amount caused my Powerwall to export to export to the grid when it had no business doing so!

Nope, still does not work after trying that. The Time Based Settings appeared this morning, so maybe the ability to enter times and rates and have them saved will work tomorrow.

On a plus, I've only been billed to electricity at 5p/kWh since 00:30 this morning and my Powerwall still has 49% left, so I would never sign up to the expensive Tesla Plan at 11p, when power costs me 5p (or less for the solar).

 

[RedMod3]

I am going to prepared few French bottle of wine for the installer for not triggering that

OK, but the installer will only set what he has been allowed to set by your DNO application; he would get in big trouble is he didn't.

 

[73henny]

I have a surveyor coming tomorrow to look at panels, battery and Zappi. They're suggesting a 4.something kW array and a Givenergy 5.2 kW battery with a hybrid inverter.
If that is what I go with how does the Zappi know if its the battery or solar that is feeding the inverter, and as such it could dump all of the battery into the car? I assume I can set the battery to charge overnight on a Go rate (once a bloody smart meter is fitted) and then the panels will just keep the battery topped until all the solar energy stops?

 

[Avendit]

I have a surveyor coming tomorrow to look at panels, battery and Zappi. They're suggesting a 4.something kW array and a Givenergy 5.2 kW battery with a hybrid inverter.
If that is what I go with how does the Zappi know if its the battery or solar that is feeding the inverter, and as such it could dump all of the battery into the car? I assume I can set the battery to charge overnight on a Go rate (once a bloody smart meter is fitted) and then the panels will just keep the battery topped until all the solar energy stops?

They put a thing called a CT clamp on your supply which can measure the overall current direction and size into or out the house, and is attached to whatever your extra power sink is. In your case the car charger, but could be an Eddie water heater etc.

If it sees any power leaving the house it turns it's load thing on to the level of what it sees leaving, then everything works to manage the import/export to 0. It's slightly more complex for car chargers as the car has a minimum charge rate that your export needs to get to before the charger can start.

 

[novemberRomeo]

I've asked the five nearest companies to me (from the authorised dealers list on tesla.com) for quotes on installing a Powerwall. A week on, only one have got back to me, and it's the same company who installed my solar (who I think are good, but perhaps expensive). As installing a powerwall is relatively simple (compared with installing solar) I am more price conscious.

They have quoted:
* Current prices on Tesla Retrofit is £8,353.00 Ex VAT - again VAT on this aspect is 20%. Earliest installation date would be August.

How does this compare to quotes other people have received? If it's similar then I'll just go ahead and book it in. If it does sound high I will try to keep shopping around....

 

[Mrklaw]

I only have one back but that was £9100 inc vat subject to site survey. So about £1k less than yours. Also August/September which is a shame to miss the summer solar period

I’m hesitant though hearing how ‘smart’ the PW is - I need it to pretty much load up on off peak most of the time and use solar for top up, but sounds like it prefers to focus on one or the other?

 

[73henny]

They put a thing called a CT clamp on your supply which can measure the overall current direction and size into or out the house, and is attached to whatever your extra power sink is. In your case the car charger, but could be an Eddie water heater etc.

If it sees any power leaving the house it turns it's load thing on to the level of what it sees leaving, then everything works to manage the import/export to 0. It's slightly more complex for car chargers as the car has a minimum charge rate that your export needs to get to before the charger can start.

How does it determine whether the power from the inverter is coming from solar or the battery though? I understand the solar can be fed back to the grid (if my car isn't being charged) but whats to stop the battery feeding the grid?

 

[Avendit]

How does it determine whether the power from the inverter is coming from solar or the battery though? I understand the solar can be fed back to the grid (if my car isn't being charged) but whats to stop the battery feeding the grid?

Ah, sorry, into a system specific question there! I would presume there is some logic upstream of the inverter that can decide what goes where when??

 

[73henny]

Ah, sorry, into a system specific question there! I would presume there is some logic upstream of the inverter that can decide what goes where when??

I'll try and find out from the surveyor tomorrow. I want a simple system that I can set and forget. Not sure I'm on the right track or not though

 

[Mrklaw]

I think you can prioritise in the myenergi settings which device gets excess energy. Assume you can count the EV charger as not a core grid device so it won’t use the battery but worth checking - report back as I have a zappi and looking at batteries too

 

[94jdh]

I only have one back but that was £9100 inc vat subject to site survey. So about £1k less than yours. Also August/September which is a shame to miss the summer solar period

I’m hesitant though hearing how ‘smart’ the PW is - I need it to pretty much load up on off peak most of the time and use solar for top up, but sounds like it prefers to focus on one or the other?

I've asked the five nearest companies to me (from the authorised dealers list on tesla.com) for quotes on installing a Powerwall. A week on, only one have got back to me, and it's the same company who installed my solar (who I think are good, but perhaps expensive). As installing a powerwall is relatively simple (compared with installing solar) I am more price conscious.

They have quoted:
* Current prices on Tesla Retrofit is £8,353.00 Ex VAT - again VAT on this aspect is 20%. Earliest installation date would be August.

How does this compare to quotes other people have received? If it's similar then I'll just go ahead and book it in. If it does sound high I will try to keep shopping around....

£8750 for 1 powewall 2 and £16500 for 2 powerwall 2's