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I just moved in into a new build and I am considering installing solar + battery. I managed to get a quote for solar + Powerwall and solar + Givenergy battery.

I also just realised the tariff for the Tesla Energy plan jumped from 12p to 24p with a higher daily fixed charge as well.

Now because I don't know exactly my consumption in this new house, I'm not sure what would be the best solution for me between the two

Pro-PowerWall:
- access to Tesla Energy Plan which seems very good if I can produce more than I consume but not sure otherwise.
- bigger capacity (13.5 vs ~10 kWh)
- nice Tesla environment next to my Model3 and the Tesla Charger on the wall :)

Pro Givenergy:
- very short delivery time (8 weeks vs 14 months for the Powerwall)
- still a very good product I suppose for off peak charging and benefiting from the solar
- slightly cheaper overall

Please give me your thoughts on what is the best move
 

Dilly

Active Member
Feb 24, 2020
3,384
3,026
Norfolk
I have Powerwalls and know nothing about Givenergy batteries.
My gut feeling would be to the quickest given the current environment.
I’ll add a small caveat; depending upon solar space, I’d be tempted to add a Powerwall as well with a couple more panels to get reduced VAT
23kWh+ storage is very useful
 

Darreno

Member
Apr 5, 2022
689
1,230
Kent
I just moved in into a new build and I am considering installing solar + battery. I managed to get a quote for solar + Powerwall and solar + Givenergy battery.

I also just realised the tariff for the Tesla Energy plan jumped from 12p to 24p with a higher daily fixed charge as well.

Now because I don't know exactly my consumption in this new house, I'm not sure what would be the best solution for me between the two

Pro-PowerWall:
- access to Tesla Energy Plan which seems very good if I can produce more than I consume but not sure otherwise.
- bigger capacity (13.5 vs ~10 kWh)
- nice Tesla environment next to my Model3 and the Tesla Charger on the wall :)

Pro Givenergy:
- very short delivery time (8 weeks vs 14 months for the Powerwall)
- still a very good product I suppose for off peak charging and benefiting from the solar
- slightly cheaper overall

Please give me your thoughts on what is the best move
I am in the same situation however no room for solar so I am looking to add a PW to the house to make the most of Octopus Go. Purely to charge over night and discharge in the day.

I have not looked at Giv yet.
 
Unless you use an obscene amount of electricity or are off grid (which by some peoples answers they think they are), you do not need battery storage the size offered by likes of power wall to take economically financial advantage of > 90% benefits of battery storage.

Learn your energy usage then base your decision based on your energy usage.
 
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Darreno

Member
Apr 5, 2022
689
1,230
Kent
Unless you use an obscene amount of electricity or are off grid (which by some peoples answers they think they are), you do not need battery storage the size offered by likes of power wall to take economically financial advantage of > 90% benefits of battery storage.

Learn your energy usage then base your decision based on your energy usage.
Our household uses on average 13kwh a day (excluding cars). Which would be perfect for the 13.5kwh capacity of the PW. I have been on a 'list' with an installer since April which was due for October however it is now looking more likely to be December. They have already said new order are now at least a 12 month lead time.

My napkin maths suggests ROI would be fairly quick given the upcoming leccy increases in Oct and then Jan. The prospect of running the house on 7.5p pkw is very temping given we could seeing 50-70p on a price cap over the coming months.

I would like to find someone who uses the PW in the same way without solar to understand how reliable it is.
 
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Not sure I understand your maths.
What’s going to make the business case for the powerwall alone is not so much the price of the electricity as such but the difference in price between the cheap rate and the expensive rate.
Last year my cheap rate was 5.5p and expensive rate was 15p so I was saving 9.5p per kW used (I’ll ignore the losses inherent to the PW charge/discharge cycle for simplicity, but they are not trivial).
On my current tariff, night time costs 8.25p and Day time costs 35.05p, so just under 30p saved per each kWh used during the day. The benefit of having the battery to load shift has trebled for me.
I really don’t know what to expect when the piece cap gets reviewed and I have to renew my tariff next June. Will the delta increase? Decrease? I don’t know, although it’s safe to assume both rates will go up significantly.
With so little certainty about future day/night price differences it’s very difficult to make any reliable projections on the ROI for battery storage alone.

What it DOES get you, however, in a significant element of energy security. Especially when there are grumbling rumours of potential rolling blackouts over winter. To me that has a significant non-monetary value, but different people will have different opinions on that.
 

PITA

Model 3 Performance
Sep 2, 2021
1,078
1,047
West Midlands, UK
Our household uses on average 13kwh a day (excluding cars). Which would be perfect for the 13.5kwh capacity of the PW. I have been on a 'list' with an installer since April which was due for October however it is now looking more likely to be December. They have already said new order are now at least a 12 month lead time.

My napkin maths suggests ROI would be fairly quick given the upcoming leccy increases in Oct and then Jan. The prospect of running the house on 7.5p pkw is very temping given we could seeing 50-70p on a price cap over the coming months.

I would like to find someone who uses the PW in the same way without solar to understand how reliable it is.

Well that's how I started... just one Single Powerwall 2, no Solar Array... single Phase backup with Tesla Gateway 2.

Installed a single Phase Smart Meter and went onto Octopus Go... (at the time I didn't even have an electric car).

I cycled the Powerwall each day, charging at night, using power during the day.

The Powerwall 2 has a 13.5 kWh storage, and 5 kW discharge. I quickly started to realise that I needed two Powerwalls to get a minimum optimal system.

The main reason was the 5 kW limitation on discharge. 5 kW isn't enough, and there are items in our home which exceed that, which ends up calling on the Grid at Peak rate.

- Electric Showers (8kW)
- Induction Hob (7kW)
- Heat Pump (8 kW)
- Ev Charger (7 kW)
- Immersion Heaters, Cookers, Microwaves, Tumble Dryers, Kettles, Washing Machines.. they all add up

So... Two Powerwalls gave me 10 kW continuously which was enough.

Also, in Winter the Powerwalls battery management system uses power to keep the Powerwall warm... plus you'll probably increase your backup threshold (which reduces your availability useable storage).

Our house uses about 25 kWh per day, and two Powerwalls are the absolute minimum for us. Ideally I'd like four Powerwalls.

54 kWh for us is perfect... enough power capability for immediate demands, and enough energy (plus backup reserves) to last a good few hours during deep Winter).

In Summer I'm looking to increase our Solar Array to 11.2 kWp ... that extra storage is ideal for that as well. Able to charge the car from the batteries upon returning home if cars are away all day.

My experience has shown me that you can never have enough power, in an all-electric powered home. Solar Panels & Battery Storage is a luxury feeling allowing an abundance of cheap power. You'll want more, as much as you can get.

- Electric Cars
- Heat Pumps
- Domestic Appliances
- Smart Home Devices
- Air Conditioning
- MVHR Systems
- Big TV Movie / Gaming Systems
 
Last edited:

Mrklaw

Active Member
Mar 5, 2020
1,800
1,175
Berkshire
I’d go givenergy. They’re now LifPO, can be installed outside like the PW and can expand by adding batteries later (still recommend an electrician but it looks very simple. And available with shorter lead times.

For returns on investment (sigh) - for pure solar utilisation I estimated 8-10 to be enough for a house using 15kwh a day - you’re topping up while using, so you only need a battery for approx 60% size of your daily usage. Anything beyond that is incremental savings but high cost so arguably not worth it.

However consider winter, and if you have a ToU tariff then it may be worth looking at covering your full 24hr usage. Previusly that was difficult to justify as its only a big benefit around 4 months of the year, and you’re not saving the full price of your electric like with solar, only the difference between peak/off peak.

But now that difference is much larger - hopefully not for long, but then energy independence and stability of pricing comes in. I’d argue sizing a battery maybe 100-120% of your daily usage starts to make sense. especially if you can install with solar so 0% VAT
 
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Darreno

Member
Apr 5, 2022
689
1,230
Kent
Not sure I understand your maths.
What’s going to make the business case for the powerwall alone is not so much the price of the electricity as such but the difference in price between the cheap rate and the expensive rate.
Last year my cheap rate was 5.5p and expensive rate was 15p so I was saving 9.5p per kW used (I’ll ignore the losses inherent to the PW charge/discharge cycle for simplicity, but they are not trivial).
On my current tariff, night time costs 8.25p and Day time costs 35.05p, so just under 30p saved per each kWh used during the day. The benefit of having the battery to load shift has trebled for me.
I really don’t know what to expect when the piece cap gets reviewed and I have to renew my tariff next June. Will the delta increase? Decrease? I don’t know, although it’s safe to assume both rates will go up significantly.
With so little certainty about future day/night price differences it’s very difficult to make any reliable projections on the ROI for battery storage alone.

What it DOES get you, however, in a significant element of energy security. Especially when there are grumbling rumours of potential rolling blackouts over winter. To me that has a significant non-monetary value, but different people will have different opinions on that.
Thank you for the reply and details. With the current detla and with the 90% efficiencies of the PW ROI would be within the warranty period using the battery simply to shift load costs.

Well that's how I started... just one Single Powerwall 2, no Solar Array... single Phase backup with Tesla Gateway 2.

Installed a single Phase Smart Meter and went onto Octopus Go... (at the time I didn't even have an electric car).

I cycled the Powerwall each day, charging at night, using power during the day.

The Powerwall 2 has a 13.5 kWh storage, and 5 kW discharge. I quickly started to realise that I needed two Powerwalls to get a minimum optimal system.

The main reason was the 5 kW limitation on discharge. 5 kW isn't enough, and there are items in our home which exceed that, which ends up calling on the Grid at Peak rate.

- Electric Showers (8kW)
- Induction Hob (7kW)
- Heat Pump (8 kW)
- Ev Charger (7 kW)
- Immersion Heaters, Cookers, Microwaves, Tumble Dryers, Kettles, Washing Machines.. they all add up

So... Two Powerwalls gave me 10 kW continuously which was enough.

Also, in Winter the Powerwalls battery management system uses power to keep the Powerwall warm... plus you'll probably increase your backup threshold (which reduces your availability useable storage).

Our house uses about 25 kWh per day, and two Powerwalls are the absolute minimum for us. Ideally I'd like four Powerwalls.

54 kWh for us is perfect... enough power capability for immediate demands, and enough energy (plus backup reserves) to last a good few hours during deep Winter).

In Summer I'm looking to increase our Solar Array to 11.2 kWp ... that extra storage is ideal for that as well. Able to charge the car from the batteries upon returning home if cars are away all day.

My experience has shown me that you can never have enough power, in an all-electric powered home. Solar Panels & Battery Storage is a luxury feeling allowing an abundance of cheap power. You'll want more, as much as you can get.

- Electric Cars
- Heat Pumps
- Domestic Appliances
- Smart Home Devices
- Air Conditioning
- MVHR Systems
- Big TV Movie / Gaming Systems

Thank you also for the detailed reply.
We have no reason and do not pull over 5kw at anytime for the moment as we have gas heating for the time being but with the outlook of switching in the future.

My view is if ROI is within the warranty period, I see no reason not to go ahead and start with one install one to make the most of Go like tariffs. Certainly better return than interest makes.
 
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PITA

Model 3 Performance
Sep 2, 2021
1,078
1,047
West Midlands, UK
Thank you also for the detailed reply.
We have no reason and do not pull over 5kw at anytime for the moment as we have gas heating for the time being but with the outlook of switching in the future.

My view is if ROI is within the warranty period, I see no reason not to go ahead and start with one install one to make the most of Go like tariffs. Certainly better return than interest makes.

No worries 👍 ☺️

Unlike our crazy house haha...

Screenshot_20220812-013223_myenergi.jpg
 
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