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looking at chopping in the runaround for an id3 as the Scalextric car market is on its arse at the moment so deals to be had. I see the VW ID platform supports vehicle to home turning the car into a massive house reserve. With 11.5kw possible via a wallbox2 car charger on single phase, the arbitrage possibilities on octopus agile would be very attractive especially come winter and more freqent negative energy costs. Anyone gone down this rabbit hole yet ?

So after a couple of false starts the battery is being installed. Went with the Givenergy all in one, with is rated at 13.5kWh and allows a 100% at that capacity. It also gives a whole house uninterrupted power supply in the event of a power cut and allows my PV to function in a power outage. There Is a hope he will install it all today, but think he will be back tomorrow finish off, he has just been called away - typical. First difficulty was getting in the upstairs plant room (through loft hatch) luckily I had installed a winch for the DHW cylinder, so we used that. The gateway unit, controls the power flow, batteries, mains power, consumer unit, PV, vehicle charge point all connect to this. This will be located directly above the consumer unit and meter. Needed to run a new earth spike to the unit and new cable for a stand-alone generator, these are inserted through the J tube going under the house. Battery and inverter, without access, trim panels installed. Had to move MVHR pipes, as the unit is free standing.

hey, I myself have solar panels and would like to increase my self-consumption. I try to run the dishwasher and washing machine as much as possible when the sun is shining. Now I'm doubting whether to buy a home battery, after some comparison MyGrid seemed interesting to me. This is because you have no installation costs and the system is expandable. What do you think about my consumption at night (fridge, freezer, stand-by consumption) could this be something or are there better ones on the market?

Wasn't sure where to post this but here's our observations after storm Eunice passed through. Initially we watched the storm gather, we could see that that the wind was strong but from inside there was no indication, no sound, no draughts. As the wind picked up something we were not expecting happened, we could hear and feel a draught. We have two fairly large sliders and at the peak of the storm, the wind was pushing against the slider so much that there was airflow between the slider and the fixed pane. Not much and not continuous but it was definitely happening. Our air test was done to passive standards (positive and negative pressure) so we're fairly certain there is no problem with the sliders because if there was then the negative pressure test would have exposed that. Anyone have a contradictory view? A short time later we had a power cut , that doesn't matter. The house is warm, the Sunamp is fully charged (minus two showers), what could go wrong? Well, we're fully electric so there was no cup of tea to sup whilst watching the storm play out. Information gleaned is that the power will be out for over 48hrs And of course there's no heating. But what does that matter because the house is toasty warm at about 21.5° and we've not had any heating on for days. And the house is almost airtight, apart from the few blasts that squeezed through the sliders. Thanks to @Adrian Walker's advice we have a CO2 monitor, well we bought a couple. It was quite amazing how quickly the CO2 PPM started to increase after the power cut. Obviously the MVHR was having a bit of "quiet time", so now we had a toasty warm passive house that was not working as planned. As night drew in it got worse because lots of candles were lit. The only solution was to open some windows and get some airflow. Out of interest, it was only the monitors that informed us of the poor air quality, it wasn't something we sensed. So, we have a toasty warm passive house but with no airflow so a couple of the 'tilt and turn' windows on opposite sides of the house were tilted. That fixed things, air quality wise, very quickly but it also meant the passive house was now going to cool down more rapidly than planned. There are no heating options, apart from the bio-ethanol fire) so we were getting ready to break out the cold weather gear. Fortunately power was restored about 12 hours after the cut. We have a fair amount of PV, and it was quite a sunny storm but of course the PV trips off in a power cut. We were meant to have a battery system but the that didn't happen. The M&E individual who specced that (and didn't provide) had wired in an emergency power supply from which we could run the fridge and freezer in the event of a power outage, which was a pretty smart idea, shame it never happened, but actually my advise to anyone building to passive standards, if they have a battery system then make sure that the MVHR will run off the batteries. That's the main thing we've learned. If you have built to passive standard and have a battery system, make sure your MVHR can run from the batteries in the event of a power cut, I suspect most battery systems will power an MVHR unit for ages. Without that, you're not in a passive house anymore. Oh, and we had the first BBQ of the season this evening. Bit nippy!

As promised a little update on the Battery Storage. Firstly i'm very glad I bought when I did, as everything battery storage wise has skyrocketed in price since, even the prospect of adding a US2000C seems unlikely for now, though to be honest, going on my usage I don't think it would add a great deal of benefit. So I'm running the Solis 5th Generation AC Coupled Inverter, which does have a couple of niggles, which at present are reducing its savings potential. Those issues are: Whenever the battery isn't at 100% SOC, it pulls an amount of power from the grid, somewhere between 60W and 100W Even when the battery is actively charging, it still pulls the same 60-100W from the grid, regardless if there is enough PV power to charge the battery and cover loads at the same time. Once the battery is 100% SOC and im generating PV more than my load, I import 0W. Pulsating loads (such as induction hob) the unit can find hard to track, due to their pulsing nature, and the delay in reading the CT clamp and acting upon it. Now my base load is around 45W, so that means that since i've had the battery, i'm actually consuming more during the nighttime than i did previously, which is a negative. I got in touch with Solis UK Support about this issue, and they say they are aware of it, and are going to be adding 2 offset values which will be user configurable to combat this problem, and they've told me it will be available in around 2 weeks time, so we shall see. So although it will be a static value, i should be able to get much nearer to 0W import from grid whilst ever there is charge in the battery, but its not at 100%, and its not over its maximum demand (around 1.8kW). To better news, aside from the issues above which should get resolved, the system is essentially running off grid now, and has been since the middle to end of february, pretty much every day without fail, just with the odd bit of import for things like kettle and oven, to cover above the 1.8kW if the Solar isn't generating enough at the time, which is getting an ever smaller occurence. So the graph above is from March, with the Red bits on the top graph being the bits of import. The bit at the top showing 22kWh import, the majority of this was during the early february days after install when solar PV wasn't doing an awful lot. As you can see I'm still exporting ample amounts to the grid also, not that it would make any difference at this stage. Until I get the full years amount, its almost impossible to say how much this will have reduced by. Today I've done a load of washing and then dried it in the heat pump dryer, and following that I ran the oven on its Pyro clean cycle, and come tea time, i'll be fully charged again and ready for the evening (Thai Curry if you were wondering!). This one I'm keeping an eye on, obviously we know that these inverters will never be 100% efficient, but from those figures i've sent 177kWh to the battery, and only been able to get 124kWh back out again. Some of this will be down to the BMS consuming power to keep the battery healthy. So the inverter is 94.0% efficient at charging (100kWh sent to the battery will yield 94kWh of charge in the battery), and 94.5% efficient at discharging (1kWh being discharged from the battery will yield 945Wh). Please correct me if my maths is off! Entirely possible as I've got the plague at the moment! For how much its changed my import amounts, another tricky one which will have to wait for the end of this month, or maybe even next. I didn't get the smart meter installed til the end of March last year, but as a comparison: March 2021 (18th to 31st) - Imported 46.9kWh March 2022 (1st to 31st) - Imported 48.3kWh And this will drop further with the firmware upgrade. Will keep you posted in another couple of months time!

Hi Folks! Having used BuildHub as a learning resource for a little while, I've pulled my finger out and got a sign-in. After a year of getting our ducks in line, we are about to apply for planning for a home on our smallholding in Somerset. It may be on the optimistic side, but we are aiming for an off-grid build, to passive house standards (intending to get certified), primarily from sustainable materials. The design is very close to complete now, and the next stage for us is to put our plans in front of a design review panel. Part of the reason for this, is that our planning application will be made under paragraph 80e (previously paragraph 79, before that paragraph 55). (A national planning policy, first established in 1997, which sets out various circumstances which can enable the erection of new isolated dwellings in the open countryside.) I understand that getting a good report from the design panel is a significant step towards success with this planning route. The fundamental plan is to try and build: A 4 bed detached home Concrete-free foundations Using load-bearing straw bale construction technique To achieve an overall carbon negative construction Off-grid A large PV array Several large lithium batteries for storage Bore hole for water WETs system to process grey/black water Achieving passive house certification We still have a lot to figure out, but I'm learning more every day. Thanks for everyone on here for contributing to BuildHub as an information resource.

After pondering battery storage for many years, and then the energy prices rocketing this last year, i finally decided to give energy storage a shot, working out how it would sit financially was extremely difficult, and a little bit of a finger in the wind, but as the batteries have a designed lifetime of 15years now, and energy prices rarely go down, I figured it would pay for itself with some profit over the long term, whilst also reducing my carbon emissions and reliance on the grid. As i'm just dipping my toe in, i've decided to just get a single US3000C Pylontech Battery for now, meaning that the max discharge W is around 1.8kW. I will see how this fits in, which will cover most of my loads, and if I see fit I can add a US2000C later on to give the full 3kW discharge. Went for a Solis AC Coupled 5th Generation Inverter, the graphs it produces are really informative. Will get round to taking the rackmount bits off at some point. Example of the graphs available: I will add bits to this thread over time about electric consumption. My annual consumption at the moment is looking to be around 1200-1300kWh before the battery, Export sitting around 2400kWh as excess from the solar farm, so be interesting to see what these figures do over the next 12 months. Cost so far £2450 including installation which was £650. An additional US2000C will be £748 if i decide to go ahead.

Battery storage may have an alternative technology on its way - the flywheel. https://www.pv-magazine.com/2022/02/24/french-flywheel-storage-system-specialist-secures-e10-million-investment/ Funny thing I did a a project paper on this subject 30 years ago. There was even a Le Mans race car with one installed in the early 90s and trams have had them installed for energy recovery and storage. Run a flywheel on magnetic bearings and in a vacuum, nearly no standing losses. Use a magnetic clutch to engage a motor/generator for power output and power input. It's not rocket science as they say, just some kenetic energy.

Hello. I am due to get a 5KW system spreed between my SW roof and S facing garden in Feb. Along side this will be 10Kw ‘9kw usable’ of batteries. I’m looking at possibly trying to figure out a way to either preheat cold feed going into combi boiler ‘might need a different boiler but it’s 15 years old’ or preheat cold mains feed going into 10.5 Kw shower. Anybody recommend a way to preheat water to set temp in either from excess power from PV’s? A question on solar array. If on a bright sunny day I’m producing 4.5KW and fire up 10.5KW shower, do I just draw 6kw from the grid? That might be a daft question? lastly has anybody have any experience with PureDrive batteries? Dc 5kw x2. Many thanks

Has anyone experience of flow batteries and specifically vanadium redox flow batteries. Just after any experiences or information. What do we think will happen with Vanadium prices as they have risen recently. Perhaps Zinc Bromide flow batteries would be better as zinc is relatively abundant. Just curious!

Not much depth to it, but some rare coverage of the issue of storing electricity. BBC website article on power storage

My Bosch 4 amp battery is showing a full charge when I put it on the charger but yet when I attach a tool it will not work, and yes I have tried different tools. When I actually click it into place on the charger the charger clicks as though everything is ok and then flashes permanent green which indicates fully charged. Is it goodbye to this battery or I have heard of things like put them in the freezer for 24 hours and then leave to come back to room temperature and then try charging again. TIA

Hi, I'm not entirely sure if this post belongs here but there are several components that I think I should consider as part of one solution: Heating and Hot Water. You may be familiar with my project from the introductions forum but I'll present you with my circumstances in any case. I currently have a Combi Boiler heating our traditionally constructed 2700sq.ft bungalow and providing hot water to 2 showers (right now we use 14000 kWh Electricity and 48907 kWh Gas per annum!). We will be updating the current building with thicker loft insulation and better windows, but will still use rads to heat this portion of the house when we complete the renovation. The new part of the house will add around 6000sq.ft and will be built to much better u values using ICF walls and SIPS roof. Here's where I'm confused, I don't know what the best system will be that can provide loads of hot water (7 showers), heat UFH in the new part and also heat the rads in the old part. I'm further confused by mhrv, I've heard this is a necessity in ICF homes, but then heard the speaker at the homebuilding show at NEC state that they're pointless for homes over a certain size. I'm open to installing an ASHP but I'm not sure whether it's necessary or even beneficial when I have the option of mains gas. Lastly, I've a good size roof pointing SE without any shading to speak of so we could potentially generate a considerable amount electricity, but I would have to consider the regulations of having a system over 4kWh and the costs associated, also factoring potential battery storage over and above Sunamp if this too makes sense to use. I don't have a clue where the feed in tariff comes in to all this! There will also be a detached annexe of around 800sq.ft and we will most likely go with UFH and 1 shower, I'm not sure how this should be incorporated in to the overall scheme or whether I should treat it separate. I know its probably a good idea to speak with an energy solutions firm and will most likely speak with Stratford Energy Solutions who have been recommended to me, however, I also know that they may have commercial interests that don't take in to account all of the factors we self builders consider.

A few years ago, I bought a couple of 100Ah 12V sealed lead acid batteries from a dealer somewhere not fr off the M3, North of Basingstoke. He had hundreds of the things, removed from data centre UPS systems I now need another couple of these, as the last two were great, and still had loads of life left in them, I've been using them for around 8 or9 years and they were 3 years old when I bought them, and they are only just beginning to show signs of losing a bit of capacity. I use these as a back up supply to keep our network and internet connection up and running during power cuts, and could really do with a couple more of these batteries. The snag is that I didn't keep a record of the place I bought them all I can remember was that they took cash and were a big warehouse place, filled with pallet loads of sealed batteries. I will need to pick them up, as they are heavy, around 60 to 80kg apiece if they are like the ones I have, They are the sort of size that looks like it'll was designed to fit laying on their side in a rack system, but any gel type sealed battery at a bargain price would do. I only draw around 3A max off these batteries when they are in use and they sit on trickle charge at around 13.5V most of the time. Does anyone have any clues as to where I might find somewhere within reasonable driving distance from here that flogs off old data centre backup batteries, please?