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Tesla Power Walls in the UK?


bikerchris

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Yes, they have been on sale here for two or three years; the current model is the Powerwall 2 I believe.  I'm not convinced that Tesla have optimised them for use here, though, as I've heard a few tales about them playing up in cold weather, failing to switch to charge mode and turning on internal heating elements that then drain the battery.  I'm sure there will be, or probably are, over-the-air firmware fixes, but the stories remind me very much of the early days of Tesla cars, where they were released to the market full of bugs and had to be continually updated to fixed them.  I'm not sure I like the business model of buying a partly-tested product and then having the manufacturer fix it through the first year or two of ownership, but have to say Tesla are far from being alone in adopting this approach, it seems.

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Yes it was, but I think there is now a better value/more capable inverter charger that works well with the Pylontech battery packs.

 

The Tesla PW2 is a nicely made bit of kit, and it's available for a reasonably good price. My concerns are over the continued glitches that are being reported by owners, together with the fact that it seems to need to be connected to the internet both to function properly and so that the firmware can be updated.  My personal preference is for a simpler set up that doesn't rely on internet connectivity, phone apps etc in order to work.

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Tease!!!

 

If I've read correctly then a 9.6KWh Sofar system is currently available for just under £2900, so actually double that and you get a good chunk more than PW2, for £5800 where i think Tesla charge £6500.

 

I'm getting a bit of a buzz off this battery cost drop phenomenon. It's a bit like when the car that you lusted after as a kid gets cheap enough for you to afford as an adult. a right buzz...

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12 minutes ago, NWGEAR said:

Spare £20k for mains anyone?

 

Eek! Care to start a new post containing the details of that quote to see if the good Buildhubbers can suggest ways of getting the price down? 

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Hi and welcome to the forum.

 

You will probably find battery storage is not worthwhile, the "free" stored electriciity is likely to cost more than the retail price when you factor in the storage system price and end of life battery replacement.

 

Why not connect the solar panels to a normal inverter so the house loads can use any generated power, with only a few panels it would be likely you can self use most of it in the house base load.

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I can second @ProDave's observation about battery storage.  We have 6.25 kWp of in-roof PV and export nearly double the amount of energy we use (right now we have the dishwasher and washing machine on and are still exporting well over 3 kW). 

 

However, even with that relatively high level of PV generation, I cannot make a Tesla PW2 cover the upfront investment, or come close.  Even a cheaper battery system only really starts to look as if it might cover the investment if I include the value to us of being able to have a standby power source during power cuts, and to get the sums to add up I had to include the capital cost of a generator to provide that function if we chose not to invest in battery storage.

 

Hopefully the price of battery storage will drop over the next few years, so that it does look to be a viable investment in future.  In the meantime, I'm going to take the leap and invest in a battery system as an early adopter, and hope to be able to report on whether or not my estimates of the likely return on investment are reasonable or not.

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2 hours ago, JSHarris said:

 

Hopefully the price of battery storage will drop over the next few years, so that it does look to be a viable investment in future.  In the meantime, I'm going to take the leap and invest in a battery system as an early adopter, and hope to be able to report on whether or not my estimates of the likely return on investment are reasonable or not.

As you know, Tesla isn't the only provider of batteries. There is for instance BYD and Sonnen for instance. In the news today, Shell have bought Sonnen as they are repositioning themselves away from an oil company to an energy company. 

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Yes, I've been following all the battery storage companies for a few years now, trying to determine which will stay the course and prove to be able to supply reliable and affordable products and which will fall by the wayside.

 

The big challenge seems to be getting products to market, and that seems to be a slow process for many of the products that have been announced over the past year or so.  Be interesting to see how things pan out over the next year or so.

 

BTW, Tesla's offering is out of my price range unless they decide to reduce prices in the very near future.

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Hi ProDave!  Thanks for your message.  

 

I'm guessing an inverter would look like a box (I'll be getting a professional to install it if that's the best route to go down).  Would this box be outside the new summerhouse with the solar panels (5 metres by 1.57 metres approx) on the roof?  Would it need to be in a waterproof 'cupboard', in the fashion of the external electricity meters some houses have outside?

 

Fran

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You can get outdoor rated PV inverters, we have one bolted to the back wall of our house.  I believe that having the inverter mounted in a shaded location outside is likely to result in longer inverter life, as the most common cause of inverter failure is failure of the internal commutation capacitors.  These have a life that is highly dependent on temperature, and running them a few degrees cooler can have a big impact on making them last much longer (I believe that it's something like a 10°C temperature reduction to almost double the working life).

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14 minutes ago, Dreadnaught said:

 

Do inverters have a cooling fan?

 

Some do, yes.  Our IP65 rated one doesn't, as it's designed to be fitted outside, so just has a large finned heat sink with a cover over it, but inverters intended for use indoors can have cooling fans.  I think there's probably an advantage in having passive cooling, as fans can and do fail.  The disadvantage of passive cooling is that the unit tends to be a bit larger.

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18 minutes ago, Dreadnaught said:

 

Do inverters have a cooling fan?

 

Big ones yes, micro ones no. 

 

I saw inside an AP Micro and most of the back of it was anodised black aluminum as a huge heatsink as they are designed to sit behind the panel on the roof. Last time I checked they had one on test for something like 4 years 24x7 at 200% load and it was still going strong. 

 

As @JSHarris will attest to, this is more about decent components such as capacitors and removing any superfluous moving parts as that is what breaks first ....

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It sounds like the inverter can go behind the solar panels on the roof of my new summerhouse.  The triangular shape of the non-flat-roof part of the summerhouse roof is 2 metres at the base with a 0.5 metre apex at 0.5 metre in.  Will there be space for the inverter (and fan if it's inside the roof) in there?  Will it need strong brackets to hold it up? (We intend for the inside of the summerhouse to be open to the apex of the roof (no false ceiling).

 

I think I prefer the idea of the inverter being outside the structure of the summerhouse (without a fan).  I imagine the output from the inverter will feed into a battery pack from which I can take power for underfloor heating (4.5 metres by 2.5 metres).  Is there a website I can look at to get an idea of how much space inverter and battery pack will need?

 

Fran

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If you wish to use underfloor heating driven by PV from the roof, then I'm afraid that I think you will be disappointed with the performance.  PV generation during the heating season is generally very poor, perhaps only 5% to 10% of the generation capacity outside the heating season.

 

Also, if trying to use solar power to drive underfloor heating, then you are probably better using solar thermal, as that has a much higher efficiency than PV, probably between 2.5 and 3 times better.  Having said that, I doubt very much if you would get anywhere near enough solar energy from the roof of any building to be able to heat it during the heating season.  We have a passive house that only needs a minimal amount of winter heating, plus a 6.25 kWp PV array in the roof, and we cannot hope to meet a fraction of our heating requirement from PV generation in the winter (and our house has 300mm of insulation under the floor and in the walls, and 400mm in the roof, plus airtight triple glazed doors and windows).

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Just now, ProDave said:

My inverter is IP65 rated but I put it inside the shed as that is a kinder (dry) environment for it.

 

Ours is underneath the eaves overhang at the back of the house, and high enough up the wall that it never gets wet.  The only thing I have to watch it the rate at which cobwebs build up over the heat sink fins.  Spiders seem to like living there, perhaps because it's a bit warmer in winter than other nooks and crannies around the house.

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3 hours ago, Fran Smitherman said:

It sounds like the inverter can go behind the solar panels on the roof of my new summerhouse.  The triangular shape of the non-flat-roof part of the summerhouse roof is 2 metres at the base with a 0.5 metre apex at 0.5 metre in.  Will there be space for the inverter (and fan if it's inside the roof) in there?  Will it need strong brackets to hold it up? (We intend for the inside of the summerhouse to be open to the apex of the roof (no false ceiling).

 

I think I prefer the idea of the inverter being outside the structure of the summerhouse (without a fan).  I imagine the output from the inverter will feed into a battery pack from which I can take power for underfloor heating (4.5 metres by 2.5 metres).  Is there a website I can look at to get an idea of how much space inverter and battery pack will need?

 

Fran

To be brutally honest, I would first work out what you'll spend and what you'll ACTUALLY generate and do some maths. ;) It doesn't sounds as if this array is going to produce a huge amount of power plus it'll have degradation ad service / replacement of inverter(s) to factor in. The sums are often quite difficult with smaller arrays, and become questionable altogether if not 'south facing' with zero shading etc.

What is the actual pitch / orientation and how many m2 please? 

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