Thorfun Posted March 17, 2022 Author Share Posted March 17, 2022 52 minutes ago, 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 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. Link to comment Share on other sites More sharing options...
Thorfun Posted March 17, 2022 Author Share Posted March 17, 2022 48 minutes ago, 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 ..?? 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. Link to comment Share on other sites More sharing options...
Thorfun Posted March 17, 2022 Author Share Posted March 17, 2022 16 minutes ago, 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. 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 Link to comment Share on other sites More sharing options...
MikeGrahamT21 Posted March 17, 2022 Share Posted March 17, 2022 2 minutes ago, 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. 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. Link to comment Share on other sites More sharing options...
SteamyTea Posted March 17, 2022 Share Posted March 17, 2022 11 minutes ago, MikeGrahamT21 said: Knowing you aren't pulling much from the grid is a nice feeling. The whole of yesterday I used 3 kWh, for absolutely everything, that is a power draw of 0.125 kW. Link to comment Share on other sites More sharing options...
Nickfromwales Posted March 17, 2022 Share Posted March 17, 2022 1 hour ago, 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 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. Link to comment Share on other sites More sharing options...
MikeGrahamT21 Posted March 17, 2022 Share Posted March 17, 2022 6 minutes ago, 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. I stand corrected. Makes sense it wouldn't be instant from a safety perspective I suppose Link to comment Share on other sites More sharing options...
MikeGrahamT21 Posted March 17, 2022 Share Posted March 17, 2022 23 minutes ago, SteamyTea said: The whole of yesterday I used 3 kWh, for absolutely everything, that is a power draw of 0.125 kW. Thats 3kWh more than i've used since back end of february 1 Link to comment Share on other sites More sharing options...
joth Posted March 17, 2022 Share Posted March 17, 2022 1 hour ago, Russdl said: My main aim is to keep the MVHR running in the next outage. 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 Link to comment Share on other sites More sharing options...
Adrian Walker Posted March 17, 2022 Share Posted March 17, 2022 2 minutes ago, 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. 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 Link to comment Share on other sites More sharing options...
SteamyTea Posted March 17, 2022 Share Posted March 17, 2022 8 minutes ago, MikeGrahamT21 said: Thats 3kWh more than i've used since back end of february I bet it isn't. It may be on imported energy, home grown is still energy. Link to comment Share on other sites More sharing options...
MikeGrahamT21 Posted March 17, 2022 Share Posted March 17, 2022 22 minutes ago, SteamyTea said: I bet it isn't. It may be on imported energy, home grown is still energy. True, but I was on about pulling energy from the grid. Link to comment Share on other sites More sharing options...
joth Posted March 17, 2022 Share Posted March 17, 2022 23 minutes ago, 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. 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. Link to comment Share on other sites More sharing options...
Pocster Posted March 17, 2022 Share Posted March 17, 2022 1 hour ago, 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. 😂 We will be living the dream ! 1 1 Link to comment Share on other sites More sharing options...
Pocster Posted March 17, 2022 Share Posted March 17, 2022 1 hour ago, 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. 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 ! 💪😁 Link to comment Share on other sites More sharing options...
Thorfun Posted March 17, 2022 Author Share Posted March 17, 2022 2 minutes ago, 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 ! 💪😁 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. Link to comment Share on other sites More sharing options...
SteamyTea Posted March 17, 2022 Share Posted March 17, 2022 (edited) 39 minutes ago, 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. 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 Link to comment Share on other sites More sharing options...
Pocster Posted March 17, 2022 Share Posted March 17, 2022 (edited) 10 minutes ago, 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. 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 Link to comment Share on other sites More sharing options...
SteamyTea Posted March 17, 2022 Share Posted March 17, 2022 10 minutes ago, pocster said: Yeah ! 80kw of storage !!!! In my build I’d be hard pushed to justify more than 30kw of storage That is badly spelt power. It is kWh of storage. Link to comment Share on other sites More sharing options...
joe90 Posted March 17, 2022 Share Posted March 17, 2022 3 minutes ago, SteamyTea said: That is badly spelt power. It is kWh of storage. Blame spell check (I do!!,) 🤣 Link to comment Share on other sites More sharing options...
SteamyTea Posted March 17, 2022 Share Posted March 17, 2022 Just now, joe90 said: Blame spell check (I do!!,) 🤣 I added them to my spell checker. Shame it does not do the grammar. Link to comment Share on other sites More sharing options...
Pocster Posted March 17, 2022 Share Posted March 17, 2022 18 minutes ago, SteamyTea said: That is badly spelt power. It is kWh of storage. I know it annoys you . The k and w come off whatever way my keyboard decides 😁 1 Link to comment Share on other sites More sharing options...
andy Posted March 17, 2022 Share Posted March 17, 2022 41 minutes ago, 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 ! 💪😁 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 Link to comment Share on other sites More sharing options...
SteamyTea Posted March 17, 2022 Share Posted March 17, 2022 11 minutes ago, pocster said: The k and w come off whatever way my keyboard decides If you did not have inbred webbed fingers you could reach the shift key. 1 Link to comment Share on other sites More sharing options...
Pocster Posted March 17, 2022 Share Posted March 17, 2022 13 minutes ago, 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 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 🙄 Link to comment Share on other sites More sharing options...
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