Possible new Tesla Powerwall this year?

[Dan F]

13 minutes ago, Thorfun said:

you can get 2 x PW2s installed for £16550! wow. that's a good price. I was quoted £9500 inc VAT for one.

I was quoted £14.5k+VAT in Janurary, but this went up to £18.5k+VAT in June (including gateway and install).

 

15 minutes ago, Thorfun said:

I would've thought that with the PWs having the ability to export the DNO wouldn't like that and does that also mean that you can't use them in a power cut?

You can use them in a power-cut.  You need DNO approval.  PW's won't export to the grid, only cover loads.  (although in 3-phase setup, using the gatway, it will export on one phase to compensate for load on other phases).

[Nickfromwales]

17 minutes ago, Thorfun said:

I'm definitely no expert but I would've thought that with the PWs having the ability to export the DNO wouldn't like that and does that also mean that you can't use them in a power cut? if not, have you considered DC batteries instead of the AC PW2?

I've seen a YT video with some Tesla do-dah that connects to your CU after 5 seconds of grid 'absence'. Not sure what it was called, but Robert Llewelyn has one in his garage. "Fully Charged" was the channel.

[Thorfun]

18 minutes ago, Nickfromwales said:

I've seen a YT video with some Tesla do-dah that connects to your CU after 5 seconds of grid 'absence'. Not sure what it was called, but Robert Llewelyn has one in his garage. "Fully Charged" was the channel.

 

yeah, sorry. I know the PWs do work in a power cut (I believe you're referring to the Gateway) I was more asking about requiring DNO approval for 2 x PW2. as I thought that just some installer saying they will limit export wasn't enough for the DNO. which @Dan F has confirmed is required. 

 

21 minutes ago, Dan F said:

PW's won't export to the grid, only cover loads. 

 

again, sorry for my error. I know they don't export, that wasn't what I meant! I meant that even if you told the DNO that the PW2s were isolated they still need approval from DNO. I know that my proposed PW2 required to be part of our G99 application.

[Nickfromwales]

5 hours ago, Wil said:

But wouldn’t that be the case with any cells I chose? If I cycle them on offsetting for 10 years, that’s all I can expect from them?

In a nutshell, yes, so minimising the capital cost is of paramount importance if you want to even glance at breakeven / RoI numbers  Folk need to remember that charging off excess and then using it of an evening is a relatively easy life for a battery system. Change the scenario to where you sign up for the Tesla / Octopus arrangement and your batter is in for a kicking, thus further reducing its useful lifespan ( can drop to 7 years of 'usefulness' vs 10 with the right amount of abuse. I'd be interested to hear what the warranty wording is like for that system in that arrangement, as they benefit from beating the shite out of the system you paid for.........and then own.........and have to maintain / repair / replace.......  

 

@Wil

I'm waiting to get a reply from a supplier for an Iconica hybrid inverter ( 11kW ) which is sub £1500, and then I can open my horizons to which battery I choose to employ ( within the manufacturers recommended connectable equipment options of course ) but I am also looking at BMS options to charge near end-of-life commercial vehicle batteries. Cheap option, with fleas that come with the dog ( monitoring / replacement etc ) but the costs should be vastly cheaper.

All depends if you want a nice looking shiny box that someone fits for you, or if you want to ( and are able to ) get your hands dirty with a bit more of a bespoke setup.

Pointless doing anything unless its really worth doing tbh.

 

Change of £9k before VAT........ https://www.photonicuniverse.com/en/catalog/full/566-20kW-Zero-Transfer-Uninterrupted-Power-Supply-UPS-System-with-48kWh-energy-storage.html

Edited August 22, 2022 by Nickfromwales

[Nickfromwales]

35 minutes ago, Thorfun said:

 

yeah, sorry. I know the PWs do work in a power cut (I believe you're referring to the Gateway) I was more asking about requiring DNO approval for 2 x PW2. as I thought that just some installer saying they will limit export wasn't enough for the DNO. which @Dan F has confirmed is required. 

 

 

again, sorry for my error. I know they don't export, that wasn't what I meant! I meant that even if you told the DNO that the PW2s were isolated they still need approval from DNO. I know that my proposed PW2 required to be part of our G99 application.

 

I thought it was only me that only opened their mouth to change feet 🤣

[SteamyTea]

37 minutes ago, Nickfromwales said:

I am also looking at BMS options to charge near end-of-life commercial vehicle batteries.

Won't that be a very short lived thing.  Vehicles battery chemistry is changing to make recycling much easier.  Once a standard chemistry is agreed on, then there will not be any end of life vehicle batteries.

 

If you have space, worth looking at lead acid and nickel iron.  Hydrogen can also be produced from NiFe batteries once fully charged, but that is only for people that think hydrogen is worth pissing their pants for.

[Wil]

Well you lot aren't helping- so many other options to think about and no clear path to what's right. 

 

I went on Octopus' website tonight to play around with the Tariffs. they offered me to fix my bills. at 78p/kWh day and 49p/kWh night. If that's reality in October (or better than the reality) then the payback is starting to tumble.

 

Nick, that system looks great, but with AGM you only get 50% DoD right? so the 48kWh immediately becomes 24kWh of battery right? and I assumed that by EoL commercial batteries, you mean the 12V type to build into banks, or did you mean the LI packs coming out of vehicles?

2 hours ago, Dan F said:

(although in 3-phase setup, using the gatway, it will export on one phase to compensate for load on other phases).

Yes, this is the conversation I had with the installer who assures me 'it's a grey area' when the DNO says no export. I can't make the battery export, but I also can't stop it if balancing or doing a Tesla tariff.

[Dan F]

10 hours ago, Wil said:

Yes, this is the conversation I had with the installer who assures me 'it's a grey area' when the DNO says no export. I can't make the battery export, but I also can't stop it if balancing or doing a Tesla tariff.

It's not grey in the sense that the DNO permissions clearly states "0 Export" on it.  The 3-phase balancing is still zero "net" export, but yes, the Tesla tariff breaks the rules. I guess Octopus must have some kind of DNO permission for this.  Paperwork aside, if you have approval for your PV to export 5kW and your G99 approved inverter is setup to export a maximum of 5kW (battery+pv) at any point in time, I don't really see the issue or know how anyone would know.

 

You can't make Powerwall export at will I don't think, but I think you might be able to do this with some other solutions.   Today would be a be a good day to do that given Octupus are paying 75p for export later today!!

[Nickfromwales]

10 hours ago, Wil said:

Well you lot aren't helping- so many other options to think about and no clear path to what's right. 

 

I went on Octopus' website tonight to play around with the Tariffs. they offered me to fix my bills. at 78p/kWh day and 49p/kWh night. If that's reality in October (or better than the reality) then the payback is starting to tumble.

 

Nick, that system looks great, but with AGM you only get 50% DoD right? so the 48kWh immediately becomes 24kWh of battery right? and I assumed that by EoL commercial batteries, you mean the 12V type to build into banks, or did you mean the LI packs coming out of vehicles?

Yes, this is the conversation I had with the installer who assures me 'it's a grey area' when the DNO says no export. I can't make the battery export, but I also can't stop it if balancing or doing a Tesla tariff.

If going for the Tesla tariff then export is defo required  That’s why they give you this “deal” isn’t it? So they can suck ‘em dry as quick as you can fill ‘em.
 

50% of 48kWh is still a bloody decent bit of storage for a domestic setting. Most decent size dwellings where we’ve installed PV plus batteries have had a 9.6kWh and that’s often difficult to routinely fill and empty ( by themselves ) every 24 hours.

 

With the multiple hybrid(s) you also get the benefit of huge rates of discharge, plus instantaneous UPS to boot. Would piss me off to be having peaks of consumption that called for support from the grid, when there’s perfectly good stored energy in the batts. 
Cheap as chips for the sizing, zero export capable out of the box, so what’s there not to like?

Yes, you’ll need a bit of room to fit the batteries, which to most will look “unsightly”, but I think my electricity bill is unsightly, so my minds made up. 
 

“Death to grid dependency”. 

[Wil]

I’m blessed with the space to put them, so that’s not an issue. Keeping them conditioned at the right temp might be more of an issue though. Given my base load of 400W I use 9.6kWh per day when I’m on holiday, so that just wouldn’t do for real life.

 

The instant UPS I understand (require to be) is a function of the Tesla PW2 and when I have 2 I get 10kW continuous, 14kW peak output. Realistically, it’s only peak winter when both ASHPs and anything else is running that I consume over 10kWh so happy to have the grid backup at that point.

 

The Tesla deal of 24p/kWh in 24p/kWh out does look pretty interesting. If it saves me money to the point where it pays back in less than the 10 years, why would I mind?

 

Basically where I’m getting to is putting the batts in and then maximising the rest of my PV. Perhaps even oversizing a bit and limiting to 3.68kW export.

 

The issue I have with 3phase, is that without buying a whole system up front, or going incredibly complex with Victron equipment, I can’t see a way to have expandable storage which can balance an imbalanced charging/ discharging situation. The gateway looks like nirvana in terms of a single box controlling all phases and after that it’s just a case of adding PWs .

 

Systems like the squirrel pod look great but add cost for the same storage. The UPS system Nick linked looks really good, but comes plus install costs (I have no way to zero rate the VAT) and I’ve no idea how 4 inverters will cope with 3 phases(although it is mentioned in the description)!

1 hour ago, Dan F said:

It's not grey in the sense that the DNO permissions clearly states "0 Export" on it.  The 3-phase balancing is still zero "net" export, but yes, the Tesla tariff breaks the rules. I guess Octopus must have some kind of DNO permission for this.  Paperwork aside, if you have approval for your PV to export 5kW and your G99 approved inverter is setup to export a maximum of 5kW (battery+pv) at any point in time, I don't really see the issue or know how anyone would know.

I believe this is it, the DNO accepts that I can export up to 11kW of solar at any one time (balanced across the phases) therefore how do they know if it’s coming direct from PV or from the batt. I believe you have to show the DNO letter when signing up to the Tesla tariff, so this sets the limit for what they can pull from your batts/ overall system at any point.

[Kelvin]

Anyone have any experience of the Puredrive  Purestorage II AC system? I’ve got a quote for battery and PV which seems reasonable in the current climate! 

[Nickfromwales]

15 hours ago, SteamyTea said:

Won't that be a very short lived thing.  Vehicles battery chemistry is changing to make recycling much easier.  Once a standard chemistry is agreed on, then there will not be any end of life vehicle batteries.

There will be plenty of large car and HGV batteries around for the next 10 years at least. I’ll worry about that again after the first 10 years has expired.  

Not lithium no. Regular car batteries. Cheap and plentiful in the used market. 

[JohnMo]

Even electric vehicles have a bog standard battery to drive the 12v stuff.

 

Leisure board, caravans etc are ok with big lead based batteries, no real justification to have a light energy dense battery, that isn't normally managed well and is cheap enough to replace every few years.

 

So normal batteries will be around for decades.

[Dan F]

1 hour ago, JohnMo said:

Even electric vehicles have a bog standard battery to drive the 12v stuff.

Tesla have moved to li-ion for 12v now, other EV manufactuer may well follow.  Lasts longer and an EV doesn't the amps that a starter motor requires.

[Nickfromwales]

On 22/08/2022 at 22:37, SteamyTea said:

If you have space, worth looking at lead acid and nickel iron.

Space a plenty, speak on Obi Wan........

[Wil]

I looked up NiFe batteries and found the below:

 

https://www.rpc.com.au/solar-news/disadvantages-of-nickel-iron-batteries.html

 

While hydrogen sounds fun, I’m not sure I’m up for constant gassing and topping up.