Thorfun Posted March 17, 2022 Author Posted March 17, 2022 On 17/03/2022 at 08:47, MikeGrahamT21 said: I think the Powerwall 2 is the only unit which seamlessly handles power outages for the whole house, others just have a seperate port where you can wire a socket up Expand not according to the marketing blurb from other manufacturers! Sonnen have a 'Sonnen Protect' which acts like the Tesla Gateway (which you have to pay for on top of the PW2) from my understanding and the Lux also has something similar built in. The Sofar has a separate 'chint' that you wire the important loads to for use during switch over. What the PW2 does have though is the 5kW throughput and 7kW peak which is nice but if you're just planning to run lights and low power stuff overnight then 3kW should be more than enough.
Thorfun Posted March 17, 2022 Author Posted March 17, 2022 On 17/03/2022 at 08:55, PeterW said: This seems a very expensive “just in case” option for something that very rarely happens. If you’re trying to protect sensitive kit such as CCTV or that sort of thing then use an off the shelf UPS..! Most modern fridge freezers will stay cold for 10-12 hours minimum and it’s not like you can run your ASHP so why not fit a wood stove too as heating backup ..?? Expand the cost of a wood stove with chimney etc wouldn't be far off a whole battery solution let alone the slight increase for one that islands the power in case of a power cut. I'm after a battery system so that I can use my excess generation at night, and having the ability to use it in a power cut is a bonus I'm happy to pay a little extra for.
Thorfun Posted March 17, 2022 Author Posted March 17, 2022 On 17/03/2022 at 09:28, Russdl said: @PeterW off the top off my head, no idea of the power draw but it’s low. As for the “why” the house air quality became pretty unpleasant during the last prolonged outage requiring windows to be opened making the ‘passive house’ just a ‘house’ which started getting cold and we have very limited options to halt that cooling. Expand and with climate change who's to say these occurrences won't become more frequent. I see no issues with doomsday planning, I do have a basement/bunker after all. when the s**t hits the fan only @pocster and I will be left in our dungeons living out the rest of our days off our battery solutions. 😂 1
MikeGrahamT21 Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 09:42, Thorfun said: not according to the marketing blurb from other manufacturers! Sonnen have a 'Sonnen Protect' which acts like the Tesla Gateway (which you have to pay for on top of the PW2) from my understanding and the Lux also has something similar built in. The Sofar has a separate 'chint' that you wire the important loads to for use during switch over. What the PW2 does have though is the 5kW throughput and 7kW peak which is nice but if you're just planning to run lights and low power stuff overnight then 3kW should be more than enough. Expand Things have probably come on a long way since i last looked, this facility isn't important to me however. Running a Single Battery i'm getting 1.8kW max output at the moment, which actually is covering a good 90% of my usage, but always have the option of adding another battery for full 3kW if i see the need, or can get a bargain US2000C. There are tangible and non-tangible benefits as with most things, in the case of Battery Storage the non-tangible benefits are more towards your eco conscience, though this is on the slim side too when you consider mining of materials to make the battery, and also its disposal at end of life, though the disposal element should have changed considerably by the time my battery is end of life. Knowing you aren't pulling much from the grid is a nice feeling.
SteamyTea Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 09:50, MikeGrahamT21 said: Knowing you aren't pulling much from the grid is a nice feeling. Expand The whole of yesterday I used 3 kWh, for absolutely everything, that is a power draw of 0.125 kW.
Nickfromwales Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 08:47, MikeGrahamT21 said: I think the Powerwall 2 is the only unit which seamlessly handles power outages for the whole house, others just have a seperate port where you can wire a socket up Expand Not seamless! A bolt on but of kit and a 5 sec delay in changeover. Robert Llewelyn is on YouTube doing a demo of his iirc. Worth a watch. Problem is, you’ll cry when you add up the supply and for Cody’s of his Tesla setup, plus the electrical work to integrate it. You’d need to live to 100 to get payback, plus if ToU tariffs evaporate it’ll be an expensive ornament.
MikeGrahamT21 Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 10:20, Nickfromwales said: Not seamless! A bolt on but of kit and a 5 sec delay in changeover. Robert Llewelyn is on YouTube doing a demo of his iirc. Worth a watch. Problem is, you’ll cry when you add up the supply and for Cody’s of his Tesla setup, plus the electrical work to integrate it. You’d need to live to 100 to get payback, plus if ToU tariffs evaporate it’ll be an expensive ornament. Expand I stand corrected. Makes sense it wouldn't be instant from a safety perspective I suppose
MikeGrahamT21 Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 10:03, SteamyTea said: The whole of yesterday I used 3 kWh, for absolutely everything, that is a power draw of 0.125 kW. Expand Thats 3kWh more than i've used since back end of february 1
joth Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 09:01, Russdl said: My main aim is to keep the MVHR running in the next outage. Expand Honestly if you have specific items you really want to keep running like this, it's probably much cheaper and more reliable to get a dedicated appropriately sized UPS for it. The MAJOR issue with using a house battery for both solar PV self-consumption and critical system support during a grid outage is it is a compromise between these 2 use cases, and it will do a half-baked job of both. This is because to get high efficiency in solar self-use, you need to empty (or very nearly empty) the battery every day to create maximum capacity to fill up when the sun shines. However if the grid outage happens on an overcast day before it's had time to charge, you'll be heading into the outage with an empty battery and no way to fill it until +24 hours. You can leave X % permanently in reserve, but you really need to size X for the total base load of the house, not just the critical items. This is fine if you're SteamyTea with a near-zero base load, but anyone else that has humans living in the house, this probably means setting aside a significant portion of the house battery for "just incase" multi-day outage scenario. For £450 you can get a 1.2kWh UPS that would keep a typical MVHR running for 2+ days, come rain or sun. Personally, I'd just plan to open a window. 3
Adrian Walker Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 10:29, joth said: For £450 you can get a 1.2kWh UPS that would keep a typical MVHR running for 2+ days, come rain or sun. Personally, I'd just plan to open a window. Expand The problem with opening windows (if the house is ~airtight you will need to open at least 2) is that that heat will escape. UPS is the best and cheapest solution and could power MVHR and broadband. 2
SteamyTea Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 10:27, MikeGrahamT21 said: Thats 3kWh more than i've used since back end of february Expand I bet it isn't. It may be on imported energy, home grown is still energy.
MikeGrahamT21 Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 10:37, SteamyTea said: I bet it isn't. It may be on imported energy, home grown is still energy. Expand True, but I was on about pulling energy from the grid.
joth Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 10:35, Adrian Walker said: The problem with opening windows (if the house is ~airtight you will need to open at least 2) is that that heat will escape. UPS is the best and cheapest solution and could power MVHR and broadband. Expand For 1 day every 3 years, I can deal with a bit of heat escaping. Compared to the £ and CO2 cost of manufacturing, transporting and keeping a UPS on constant standby, an open window for a couple hours a year is completely negligible. And we only really heat the house for 4 months a year, so odds are the outage occurs in summer when an open window is most welcome.
Pocster Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 09:47, Thorfun said: and with climate change who's to say these occurrences won't become more frequent. I see no issues with doomsday planning, I do have a basement/bunker after all. when the s**t hits the fan only @pocster and I will be left in our dungeons living out the rest of our days off our battery solutions. 😂 Expand We will be living the dream ! 1 1
Pocster Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 10:29, joth said: but anyone else that has humans living in the house, this probably means setting aside a significant portion of the house battery for "just incase" multi-day outage scenario. Expand Because I suffer no outages ( apart from the ones I generate ! ) My Pw2 has the minimum set for reserve in such a situation I.e 1% . I think @Thorfun whom has 3 phase I believe needs to suck it up and have 3 pw2 ‘s installed . Problem solved ! 💪😁
Thorfun Posted March 17, 2022 Author Posted March 17, 2022 On 17/03/2022 at 11:33, pocster said: Because I suffer no outages ( apart from the ones I generate ! ) My Pw2 has the minimum set for reserve in such a situation I.e 1% . I think @Thorfun whom has 3 phase I believe needs to suck it up and have 3 pw2 ‘s installed . Problem solved ! 💪😁 Expand how about 2 x Squirrel PODS with 8 x 3.3kW batteries per phase? so that's 79.2kW total storage with 7kW discharge per phase.
SteamyTea Posted March 17, 2022 Posted March 17, 2022 (edited) On 17/03/2022 at 11:02, joth said: And we only really heat the house for 4 months a year, so odds are the outage occurs in summer when an open window is most welcome. Expand Odds are that the outraged come with a storm from an unexpected direction. Those trees will take 30 years to grow back and be a problem. It is not like flooding. That tends to be a problem after a prolonged dry spell. Edited March 17, 2022 by SteamyTea
Pocster Posted March 17, 2022 Posted March 17, 2022 (edited) On 17/03/2022 at 11:37, Thorfun said: how about 2 x Squirrel PODS with 8 x 3.3kW batteries per phase? so that's 79.2kW total storage with 7kW discharge per phase. Expand Yeah ! 80kw of storage !!!! In my build I’d be hard pushed to justify more than 30kw of storage . Though I currently just have 13 ( pw2 ) and SE battery due May ( another 10 ) - I always consider the EV as ‘storage ‘ - so that’s an additional 54. If the SE seems good certainly plan to add another . Then I’ll be the winner ! ( don’t go and include your EV and upset me ) . What’s you pv generation? ( mine 4 but soon 7.2 ) Edited March 17, 2022 by pocster
SteamyTea Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 11:48, pocster said: Yeah ! 80kw of storage !!!! In my build I’d be hard pushed to justify more than 30kw of storage Expand That is badly spelt power. It is kWh of storage.
joe90 Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 12:00, SteamyTea said: That is badly spelt power. It is kWh of storage. Expand Blame spell check (I do!!,) 🤣
SteamyTea Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 12:04, joe90 said: Blame spell check (I do!!,) 🤣 Expand I added them to my spell checker. Shame it does not do the grammar.
Pocster Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 12:00, SteamyTea said: That is badly spelt power. It is kWh of storage. Expand I know it annoys you . The k and w come off whatever way my keyboard decides 😁 1
andy Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 11:33, pocster said: Because I suffer no outages ( apart from the ones I generate ! ) My Pw2 has the minimum set for reserve in such a situation I.e 1% . I think @Thorfun whom has 3 phase I believe needs to suck it up and have 3 pw2 ‘s installed . Problem solved ! 💪😁 Expand I've got 3 phase and have gone for 1 x Powerwall with important loads on phase 1 (protected phase), so you don't need 3 unless you really want to... It's worth mentioning in case it hasn't been said but Powerwall install is zero-VAT rated as part of new build, so if you think you might need 3 then "cheaper" to get them all at once
SteamyTea Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 12:19, pocster said: The k and w come off whatever way my keyboard decides Expand If you did not have inbred webbed fingers you could reach the shift key. 1
Pocster Posted March 17, 2022 Posted March 17, 2022 On 17/03/2022 at 12:20, andy said: I've got 3 phase and have gone for 1 x Powerwall with important loads on phase 1 (protected phase), so you don't need 3 unless you really want to... It's worth mentioning in case it hasn't been said but Powerwall install is zero-VAT rated as part of new build, so if you think you might need 3 then "cheaper" to get them all at once Expand Absolutely. 20% saving NOW Even if I add another SE battery ‘later’ it will be before my build is signed off so can qualify for the vat exemption. Good excuse why it takes so long 🙄
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