Powerwall versus Givenergy batteries

[khyros]

this is all super confusing to me.
We use around 15kwh/day on summer and anywhere between 20 and 50 kwh/day in Winter, as we have a heat pump.
We are also getting a Model 3 next month.

What is the best solar/battery set up that would allow us to

1) charge the batteries during the day
2) have the car charge at night and use any left over Go Faster cheap time slot to top up the battery
3) have the house run on battery power most of the day when it's more expensive. We are barely at home during the week.

From a remote solar survey we should be able to get around 16 panels (total 6.40 kWp system)

 

[browellm]

this is all super confusing to me.
We use around 15kwh/day on summer and anywhere between 20 and 50 kwh/day in Winter, as we have a heat pump.
We are also getting a Model 3 next month.

What is the best solar/battery set up that would allow us to

1) charge the batteries during the day
2) have the car charge at night and use any left over Go Faster cheap time slot to top up the battery
3) have the house run on battery power most of the day when it's more expensive. We are barely at home during the week.

From a remote solar survey we should be able to get around 16 panels (total 6.40 kWp system)

Heatpump is the killer here. Probably best going with a couple of Powerwalls if you can afford it because of the throughput capability. I think @PITA also has a heatpump and can provide some insight.

 

[RedMod3]

Contacted 5 solar installers and only 1 has responded.. which coincidentally happens to be a local one.

I'd rather multiple quotes but I guess they're all so busy they can pick and choose at the moment so getting a quote from someone who might have to travel across the country is going the be hard.

this is all super confusing to me.
We use around 15kwh/day on summer and anywhere between 20 and 50 kwh/day in Winter, as we have a heat pump.
We are also getting a Model 3 next month.

What is the best solar/battery set up that would allow us to

1) charge the batteries during the day
2) have the car charge at night and use any left over Go Faster cheap time slot to top up the battery
3) have the house run on battery power most of the day when it's more expensive. We are barely at home during the week.

From a remote solar survey we should be able to get around 16 panels (total 6.40 kWp system)

Khyros

Your consumption is identical to mine; we are all electric and use heat pumps for heating in winter and cooling in summer. I would suggest:

Two powerwalls and 5-6kW of solar. We have 5.1kW solar net and our second PW will be installed when it arrives.

I have accepted that our two EVs will always be charged at night at 5p on the GO tariff; I will not complain at 1.25p/mile. The PW will also charge at 3.6kW each at night.

You will get extreme solar on some days and the PWs will fills up, and here my solar diverter cuts in to heat our water by the immersion heater. If I still have excess energy, then I'll manually connect one of the cars up to use it.

One tip, make sure you really understand the wiring diagram of your installer. Our 5th terminal power does not go through PW and this supplies the bottom immersion heater and our off-peak circuit for the Granny. The 7.4kw EV chargers are on non-backup.

 

[PITA]

this is all super confusing to me.
We use around 15kwh/day on summer and anywhere between 20 and 50 kwh/day in Winter, as we have a heat pump.
We are also getting a Model 3 next month.

What is the best solar/battery set up that would allow us to

1) charge the batteries during the day
2) have the car charge at night and use any left over Go Faster cheap time slot to top up the battery
3) have the house run on battery power most of the day when it's more expensive. We are barely at home during the week.

From a remote solar survey we should be able to get around 16 panels (total 6.40 kWp system)

This is our setup and how we use it.

7.2 kWp Solar Array (East / West) with a 5 kW SolarEdge HDWave Inverter (18 x 400w Sunpower Maxeon-3 panels). This means we produce a maximum of 5 kW of Power from our Solar Array.

27 kWh Tesla Powerwall Storage (2 units) & Tesla Gateway 2. This means we can discharge at 10kW, and charge from the Grid at 10kW, and isolate from the Grid during a blackout which means our system stays operational. The two Powerwalls and gateway backup a single phase to the house.

22 kW 3 Phase Ev Charger. This means we can charge a car directly from the Grid Power at 11 kW or 22 kW (including Night Cheap Rate)

7 kW Single Phase Ev Charger. This means we can charge a second car directly from the Powerwall Batteries (Solar or Cheap Grid), or Grid at 7 kW (including Night Cheap Rate)

8 kW Heat Pump Air to Air. This means we can Cool or Heat the House during Summer and Winter.

3 Phase Smart Meter and Octopus Go Tariff (7.5p off-peak / 30p peak / 25p Standing Charge)

Octopus Smart Export Guarantee Tariff (4p) for exported power

>>>>>>>>>>>

On a perfect Summers Day we generate about 45 kWh of Solar Energy during each day, which is just about enough. But in Winter it can be as little as 65 kWh a MONTH. A 6 kWp Array South Facing would be good, get as much as you can.

We use about 20 kWh per day to run the house... another 15 kWh per day to run the Heat Pump, and up to 60 kWh per day for cars charging. Depending on time of year, Heat Pump use and how much vehicle charging we do.

>>>>>>>>>>>

Having two Powerwall Batteries gives you the option to discharge them at 10 kW power. This is important because you can wire in a 7 kW Ev Charger directly to the Tesla Gateway 2 box. Which allows you to manually discharge Powerwall battery capacity into the car at 7kW, allowing more room in the Powerwalls for more Solar.

During Winter, two Powerwalls will get you through to about 6pm and then they'll start running low. Ideally I'd like three Powerwalls. But I'm going to wait now until the Powerwall 3 is released (whenever)... and use that as my third Powerwall to get me to about 50 kWh hopefully.

>>>>>>>>>>>

If you ever get the chance to get a 3 Phase Supply... seriously consider it.

During Winter the Octopus Go cheap night rate, we can now charge our Powerwalls at 7kW, my Wifes car at 7kW, my own car at 11kW and run the house... all at the same time. It's a massive benefit to draw that much power from the Grid at limited low cost periods. We can get about 100 kWh per day on cheap rate in a 4 hour period

 

[khyros]

This is our setup and how we use it.

7.2 kWp Solar Array (East / West) with a 5 kW SolarEdge HDWave Inverter (18 x 400w Sunpower Maxeon-3 panels). This means we produce a maximum of 5 kW of Power from our Solar Array.

27 kWh Tesla Powerwall Storage (2 units) & Tesla Gateway 2. This means we can discharge at 10kW, and charge from the Grid at 10kW, and isolate from the Grid during a blackout which means our system stays operational. The two Powerwalls and gateway backup a single phase to the house.

22 kW 3 Phase Ev Charger. This means we can charge a car directly from the Grid Power at 11 kW or 22 kW (including Night Cheap Rate)

7 kW Single Phase Ev Charger. This means we can charge a second car directly from the Powerwall Batteries (Solar or Cheap Grid), or Grid at 7 kW (including Night Cheap Rate)

8 kW Heat Pump Air to Air. This means we can Cool or Heat the House during Summer and Winter.

3 Phase Smart Meter and Octopus Go Tariff (7.5p off-peak / 30p peak / 25p Standing Charge)

Octopus Smart Export Guarantee Tariff (4p) for exported power

>>>>>>>>>>>

On a perfect Summers Day we generate about 45 kWh of Solar Energy during each day, which is just about enough. But in Winter it can be as little as 65 kWh a MONTH. A 6 kWp Array South Facing would be good, get as much as you can.

We use about 20 kWh per day to run the house... another 15 kWh per day to run the Heat Pump, and up to 60 kWh per day for cars charging. Depending on time of year, Heat Pump use and how much vehicle charging we do.

>>>>>>>>>>>

Having two Powerwall Batteries gives you the option to discharge them at 10 kW power. This is important because you can wire in a 7 kW Ev Charger directly to the Tesla Gateway 2 box. Which allows you to manually discharge Powerwall battery capacity into the car at 7kW, allowing more room in the Powerwalls for more Solar.

During Winter, two Powerwalls will get you through to about 6pm and then they'll start running low. Ideally I'd like three Powerwalls. But I'm going to wait now until the Powerwall 3 is released (whenever)... and use that as my third Powerwall to get me to about 50 kWh hopefully.

>>>>>>>>>>>

If you ever get the chance to get a 3 Phase Supply... seriously consider it.

During Winter the Octopus Go cheap night rate, we can now charge our Powerwalls at 7kW, my Wifes car at 7kW, my own car at 11kW and run the house... all at the same time. It's a massive benefit to draw that much power from the Grid at limited low cost periods. We can get about 100 kWh per day on cheap rate in a 4 hour period

Wow these are all very detailed replies, thanks a lot. I guess I know very little.
Considering the trouble I'm even getting to get solar surveys done, not sure how will I ever get an installer to do such a complex project.

 

[PITA]

Wow these are all very detailed replies, thanks a lot. I guess I know very little.
Considering the trouble I'm even getting to get solar surveys done, not sure how will I ever get an installer to do such a complex project.

What helped me, is I did a lot of research... Read articles, read case studies, asked people who'd got it all.

Then I knew what I wanted, and was able to direct the installers on what the target goal is.

How they got there is up to them...

Otherwise you run the risk of getting what they want to install... and it's not always optimised for your requirements.

 

[Tony Hoyle]

Problem is getting an installer to talk to in the first place at the moment..

 

[Plagued]

If you ever get the chance to get a 3 Phase Supply... seriously consider it.

During Winter the Octopus Go cheap night rate, we can now charge our Powerwalls at 7kW, my Wifes car at 7kW, my own car at 11kW and run the house... all at the same time. It's a massive benefit to draw that much power from the Grid at limited low cost periods. We can get about 100 kWh per day on cheap rate in a 4 hour period

Nice bit of info there. I'm looking for something almost the same as you, and strangely my house already has 3 phase, I'm just only connected to 1 at the moment (currently in discussions with Octopus about getting the other two connected, but unsurprisingly it's hard to get hold of them) I'm also fused at 100A so I could actually pull a fair bit without the other two phases anyway.
The thing for me is I can't see a real justification of getting the power wall over a much cheaper battery pack. I could get almost twice the capacity for the same price. I doubt I'd use the grid integration as I use too much power to really be in a position to sell battery capacity for grid stabilisation and having a single circuit covered for blackouts would be fine for me. And the other issue is availability with hearing people waiting over 9 months for a powerwall and still no delivery estimate. I'd potentially want to get the battery in before the solar as over winter I'd benefit more from storing off peak power than solar generated power.
But alas I'm in the same position as others here, with it being almost impossible to get quotes as everyone's too busy.
I'm tempted to do 90% of the work myself and just get someone into commision it all.

 

[PITA]

Nice bit of info there. I'm looking for something almost the same as you, and strangely my house already has 3 phase, I'm just only connected to 1 at the moment (currently in discussions with Octopus about getting the other two connected, but unsurprisingly it's hard to get hold of them) I'm also fused at 100A so I could actually pull a fair bit without the other two phases anyway.
The thing for me is I can't see a real justification of getting the power wall over a much cheaper battery pack. I could get almost twice the capacity for the same price. I doubt I'd use the grid integration as I use too much power to really be in a position to sell battery capacity for grid stabilisation and having a single circuit covered for blackouts would be fine for me. And the other issue is availability with hearing people waiting over 9 months for a powerwall and still no delivery estimate. I'd potentially want to get the battery in before the solar as over winter I'd benefit more from storing off peak power than solar generated power.
But alas I'm in the same position as others here, with it being almost impossible to get quotes as everyone's too busy.
I'm tempted to do 90% of the work myself and just get someone into commision it all.

I chose the Tesla Powerwall for a few reasons.

1) It can be installed outside in the rain. This is really important to me, as I don't want high capacity battery storage within the House. If it catches fire, it won't stop and poisonous gasses are also an issue. My family safety was too important. I even had all the Solar Electrics kept out of the Roof Space.

2) Tesla Gateway 2. Islanding our Solar & Battery kit was a priority. The Tesla Gateway 2 not only does this but it has 8 additional fused connectors. 4 connectors which are Backup Side, and 4 connectors which are Grid-Tied side. This means you can wire up a 7kW Ev Charger on non-backup side which can pull power from the Grid at night, or Powerwalls Stored Solar Power during the day. If the Grid has a blackout, then the Charger fails with the Grid (in my case) because I didn't want it draining the Powerwalls. Connecting stuff to the Gateway 2 unit free's up space (slots) in your Consumer Board.

3) Integration with the Tesla App. I can see my car, I can see my Powerwalls, I can see where all the power is coming and going... I can start charging from my App, I can reschedule Battery charging... it's my go-to house power controller.

4) Storage Capacity is important. But what is also very important is Discharge Capability. Powerwalls discharge at 5kW each. So if you have two of them, they can discharge at 10kW. This is very important because you can run reasonably high loads in the house, and not pull from the Grid (in Winter this'll be an issue). As an example, with two Powerwalls you can run a 7kW Ev charger straight from the Powerwall stored solar... at 7 kW !! ... you're not stuck with waiting for the minimum 1.4kW Solar generation level before it'll start charging your Ev. Having another battery setup with a low discharge capability just means you run the risk of pulling from the Grid all the time at peak rate. No point having all that storage capacity if your discharge capability stops you getting to it...

Your situation with 3 Phase Supply but Single Phase to the house, would be identical to my setup.

This means your Powerwalls would backup the Single Phase to the house. Provide the Solar to the house. Provide power to your 7kW Ev Charger.

Then if you really wanted to get going... fit a 3 Phase Smart Meter, fit a 3 Phase Distribution Board alongside it. Wire in another separate 3 Phase Ev Charger and have all the options open to you.

You can then charge your car at 7 kW from Grid, or from Powerwall Solar. Or you can use the other 3 Phase charger to charge from Grid Only at 11kW. This is good because the 3 Phase charger isn't interrupting your Powerwalls or Solar setup. It's just downstream getting Grid Power. So no unneccessary Powerwall drain. You can then use all of it, all at once, and get some nice charging speed benefit on 3 phase, no worries.

 

[nufan]

Can the Tesla Gateway 2 and/or app coordinate the solar/car to charge the car without grid or battery draw during the day? i.e. only with excess solar.

Two different scenarios I might want to coordinate (1) the above - wanting the car to suck in excess solar during the day once the batteries are full; (2) night time cheap-Go-period car charging - where the GivEnergy offering can be told to hold off discharging to the car, but I’m unsure if the PW2 offers the same functionality.

Can both battery solutions handle both requirements?

I spoke to GivEnergy the other day - their EV solar diverter isn’t on the market yet - so I suspect it can’t do (1) natively unless some API/Rpi solution is possible? They said their newer larger batteries are two months from these shores btw.

 

[94jdh]

" their newer larger batteries are two months from these shores btw.*

yes, spoke with them a while ago, it's also advertised/announced on their Facebook page for June release.

 

[PITA]

Can the Tesla Gateway 2 and/or app coordinate the solar/car to charge the car without grid or battery draw during the day? i.e. only with excess solar.

Two different scenarios I might want to coordinate (1) the above - wanting the car to suck in excess solar during the day once the batteries are full; (2) night time cheap-Go-period car charging - where the GivEnergy offering can be told to hold off discharging to the car, but I’m unsure if the PW2 offers the same functionality.

Can both battery solutions handle both requirements?

I spoke to GivEnergy the other day - their EV solar diverter isn’t on the market yet - so I suspect it can’t do (1) natively unless some API/Rpi solution is possible? They said their newer larger batteries are two months from these shores btw.

Yes, you can set up a MyEnergi Zappi Ev charger to charge the car during the daytime, and avoid Grid, and avoid home battery drain. The issue here is Ev Charging standards only charge at a minimum of 1.4 kW. So if your Solar is producing 1.3 kW, it'll export to the Grid... not the car. To avoid this limitation you could have two Powerwalls that discharge at 10kW... then charge the car from the Powerwalls manually... at 7 kW whenever you want. This'll release more storage for more Solar.

With the Powerwalls, yes you can use a Zappi Ev Charger to charge the car during the night time low cost tariff... and charge the Powerwall at the same time.

 

[Tony Hoyle]

Got this today from solarguide... "While we haven’t had any interest just yet, that doesn’t mean we’re giving up - quite the opposite! We’re going to keep working away behind the scenes to ensure you get your free quotes."

And this is just getting quotes! F knows how hard it is to get an actual install..

I may have to give up on the idea.

 

[Mrklaw]

Got this today from solarguide... "While we haven’t had any interest just yet, that doesn’t mean we’re giving up - quite the opposite! We’re going to keep working away behind the scenes to ensure you get your free quotes."

And this is just getting quotes! F knows how hard it is to get an actual install..

I may have to give up on the idea.

I didn't get any response from suppliers through them :/

 

[exlatccatsa]

I found this YouTube video from a guy who's has had both Powerwall and Givenergy and a few others and found shortcomings with them. He explains it all in the video.

Its reassuring to see he's settled on a similar setup to mine Victron and Pylontech, which hopefully means I'm on the right track. But he has a few good ideas that I may use for my setup.
I learned a lot from him so I thought I'd share it.

 

[Darreno]

Does anyone know the rough cost on a power wall to be installed currently. I have just been quite £14k installed (basic easy installation). To my calculation that’s £4k for a day installing.

 

[Tony Hoyle]

That seems high. From looking around a simple install should be about 9k (eg. Tesla Powerwall 2 - store excess solar energy, back-up power - Joju Solar).

Getting an actual quote though has proved rather difficult and the only one I've got that far with said there's no availability until 2023..

 

[spon88]

Does anyone know the rough cost on a power wall to be installed currently. I have just been quite £14k installed (basic easy installation). To my calculation that’s £4k for a day installing.

For comparison I'm paying just under 15k for a 7.9kwp solar array, 5kw inverter, 2 x 9.5kwh batteries, solar divert for water heating and a Zappi charger. Also an emergency power circuit in case of power cut (very rare where I live).

Negatives of my system versus Powerwall is that it won't do automatic house back-up in the event of power failure and I'm also restricted to 3.6kw draw - but that covers most of my usage when the batteries will be running. Positives are that I should have better integration with certain energy tariffs and safer battery technology.

I can afford Powerwall but value wise, it doesn't make sense for my particular needs.

 

[browellm]

Negatives of my system versus Powerwall is that it won't do automatic house back-up in the event of power failure

If you want this the GE system is capable. You'll have to ask your installer to design the circuit though, and would probably involve a secondary CU being fitted. It would certainly increase the overall price.

 

[RedMod3]

Does anyone know the rough cost on a power wall to be installed currently. I have just been quite £14k installed (basic easy installation). To my calculation that’s £4k for a day installing.

£18.9k for 2 Powerwalls, 1.5kW ( 4 x LG 375W Black panels 25yr warranty) and a 1.5kW Solaredge inverter.