December is the first month of summer here in Adelaide South Australia. However it has been a bit cloudy. From the 6.3kw north facing system on the house, generated 920 kwh. From the east west facing 6.5kw system on the shed, generated 995 kwh. Total generation from both systems is 1.91 mwh for December. The total generation for 2023 is 15.11 mwh considering the the system on the shed was only installed at the end of April 2023.
Interesting plan. I was actually looking at the other way around of adding more solar panels rather than battery. While they will only help a little bit in winter the amount of extra power sold during the other 8-9 months of the year should help to offset the winter costs.
It might be worth seeing how much you can top up your batteries during the day (when your EV is at home) when you get onto the Intelligent Octopus Go tariff before you decide to invest in another battery......We have always been offered the same regular daytime additional slots (10-30 -12 and 2-30 -4) and our evening charge always starts well before 11-30pm (often from 8-30pm onwards) which is great for topping up the batteries if needed.
I agree, I was surprised just how many extra hours you get especially over the Christmas and new year holidays. It would also be cheaper to change to a compatible charger if that is required.
Yes, indeed, that's worth considering but difficult to calculate when I don't have any reliable data on it. Might have to be a bit of finger in the air kinda thing.
We hit 96.4kWh. It’s our first December with solar so I don’t have anything to compare with. It seemed dark but on the plus side less cold which kept our heating demand lower than last year. Can’t wait for less gloomy days!
Really like your videos. I've got 4kW of solar with enphase edge inverters. Here are my Dec generations for the last 11 years:- 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 Dec 130.2 163.7 98.4 134.1 127.8 124.0 148.8 114.7 80.6 127.1 85.8 Dec 2023 was the second worst Dec within that time period. What was also interesting was that there were only 8 days in that month when my panels produced over 3.5kWh, so 23 days when every drop of generation was being consumed by the house's 'base' load (of 300w) and therefore no excess. 😞
You need to consider the charge rate and time alongside batteries as at some point you can’t charge them up in the off peak period. We hit that limit so can’t add more battery without larger inverter capacity.
Yeah, I added a text box to that effect as I forgot to mention it during recording. If we get onto Intelligent Go that would give us enough time, even with some extra capacity, so hopefully we can achieve that in time for next Winter.
I’ve been thinking about doing the same, I have a moixa 4.8 kWh battery and am considering adding the same again or a 9.6 unit, this video I proving extremely helpful with those considerations , many thanks.
Ditto for us, Spalding Lincs since 2012 on our original array south facing. Combined array (new plus original) was 5.5kw 105.3. Thank goodness for the Powerwall 2 capacity and the Intelligent Go six hour cheap rate window.
Purely from my perception as to how often it was gloomy and raining it felt like December was rubbish. We got 74kWh. Just checked and the previous December was 130kWh. Our consumption from the grid went from 387kWh to 624kWh which might have had something to do with the boiler dying on Christmas Day and needing to run various forms of highly inefficient electric heating for 4 days! Managed to use over 60 kWh on one day! Somewhat frustrating when we got it fixed that the problem was the outflow from the boiler (condensing pipe?) was backed up because the drains were blocked. Had I known (I'm not a plumber, I would never have figured it out) I could have fixed it within 10 minutes by unblocking the drain. Live and learn....
We generated 110kwh in our first ever December, 16 x 385w panels. Pure South facing, in Yorkshire, no shading, using micro inverters. Quite happy with that after reading others numbers in the comments.
Thanks for this Tim, really helpful to see that you were also way low compared to the PVGIS tool, we were too and I was wondering if it was something specific to our installation but clearly not. Tbh, recent savings sessions have more than made up for the shortfall.
Good update Tim 😊. We installed 3.8kw solar panels in Dec and already have an 8.2GE battery. I was genuinely surprised to see any solar at all in Dec, but my naivety showing there! Overall though our solar data is fairly similar, so I’ll be paying attention to your analysis over the next few months. On an aside, I had the first nearly totally clear sunny day today and generated 9kwh. Happy with that and even treated the EV to around 7%!! That’s the dream!
I notice our unit prices are different. Switched to Octopus Go from Octopus Flux in mid October via a telephone call with Octopus. Unit price 00:00-04:30 7.5p other times 40.9p. Used 109 peak units 22 of those were for recharging the batteries after a saving session. ASHP uses 1.5 as much power when outside temperature is negative celsius compared to average of 4-7 celsius so had to import at peak rate on four days in December. Only participated in the last three saving sessions which brought the bill from Octopus down from £99.48 to £41.76
I think different areas of the country get different rates, but I'm surprised your off-peak is that low. I thought 7.5p was the Intelligent Go rate. Although your day rates is a lot higher. Weird. Still, as long as you can use mostly off-peak it's all good!
Your point about ability to fully charge during off peak periods is a good one. This charge capacity is a combination of both inverter and battery. More by luck than anything else, our 5.5kW inverter and x4 5.32kWh batteries seem a pretty good match for our peak winter use and the 3hr Octopus Flux window, but that wasn’t due to any real calculation on my part 🤦♂️
Ha! Well, I'm glad it worked out for you. If we can get onto Intelligent Go then we should have no problem charging an extra battery too, so with any luck we can achieve that by next Winter.
Tim Interesting data I look forward to the spring to see how much peak you use. Great news on the no vat on additional batteries. Having the extra battery may in the milder winter months really save you cash maybe with some extra panels as well
My 7.56kWh Solar PV also split over an E/W roof only gave 64kWh. It is the worst December as usually around 100kWh. Overall 2023 was down on our average. Our ASHP for DHW and Heating used 517.72kWh for our 5 bed detached 1973 house.
Hi Tim, December was dismal. I’m not far from you and mine produced less than half of 2022 and 2021 levels. Although unlikely to hugely affect production, I’m thinking about having the panels cleaned for the first time in March. Rob
I've had my panels for 11 years. Year before last I got my window cleaner to use that pure water cleaning stuff on 8 of my panels. I have Enphase Edge inverters so can see what each panel produces individually each day. I took some readings of all panels before the cleaning picking a couple of 'good' days and a couple of 'poor' days, then did the same after the the 8 were cleaned. IF there was any improvement, I couldn't detect it between the pre and post cleaning figures. So, for 10 years, cleaning didn't give any perceivable improvement, so I'll just leave them. I do from time to time do a check of the panels (production) to confirm all 16 are still doing well, even though I get email notifications of any issues that arise from Enphase.
@@cgreene3745 that is fascinating, thanks for sharing your experiences. My father in law has never cleaned his panels in 12 years and has also not noticed any change over that time.
We're also in sunny Gloucester and generated a monumental 77kWh from our 7.6kW EW array. My suspicion is, you'll find extra storage isn't worth it, even if you could charge overnight, which you can't on Go as the charging period isn't long enough. I'm assuming you're hoping the GE charger will be compatible with IOG soon, in which case don't forget to use the different prices in your calculations.
Yes, indeed, we would need to get onto IOG for extra battery to be worthwhile. It'll certainly be a close run thing based on a back of the envelope calculation I've done. There are a few other benefits to more storage too though, over and above the reduction in heating costs, so that might swing it.
This will be a quick one!! I've decided to get an extra battery in Feb when the VAT rules change. Extra solar panels may come later. Went onto Intelligent Octopus Go last month so now get a longer night rate tariff at 7p/kW/hr.
Tim, thanks for another interesting video. 2 questions. 1. I have an air to water heat pump and I run this 24/7 working on weather compensation. I have a daytime temperature set at 20C with night-time set back temperature of 17C. For comparison, how do you run your air to air system? 2. I have two GE 8.2 kWh batteries daisy-chained to a GE AC coupled 3.0 inverter. I am on Cosy tariff and, in December, my batteries lasted through the day on the two 3 hr cheaper slots. I would never manage this with one cheaper and longer overnight slot - I can't get enough juice into the batteries! However with temperatures dropping, even my batteries will probably run dry before reaching the next cheaper slot. An extra battery wouldn't help unless I also got another inverter (which I believe that GE do not support). I also worry that we are basing ROI on current tariffs and National Grid policies. This scenario will likely change in the future, perhaps with electricity usage controlled more centrally. And batteries are expensive. I will be interested to see your financial breakdown for an extra battery. My gut feel is that it wouldn't be viable and I would be better off getting as many panels on my roof as possible. Perhaps the National Grid should pay for out batteries as we should be helping the grid with national distribution of electricity! Thanks Rob.
We run our A2A units from 6am to 20:30 with the temperature set to 18 in the less used rooms and 19/20 in the lounge and office where we spend most time. I manually adjust as required during the day if we need a little boost. The single longer overnight period has the advantage that it's a lot cheaper than the cosy off-peak rate so we can use that to charge our EV and heat our water at that time too, so that works well for us. There are other advantages of more battery capacity over and above helping to cover the heating (and assuming we can get onto Intelligent Octopus Go which has six hours of overnight rate), so I'll be discussing all of that in the Spring when I present my analysis. In the long run prices will continue to go up, don't bank on them coming back down to the level they were a couple of years ago. They may temporarily drop for a time but they'll absolutely go back up more over the long run.
The spreadsheet I whack a few figures in each day calculates how much we'd save with a 2nd 5kWh battery. Our installer originally priced up 2 but I didn't want to commit to that at the time as the option was always there to add it later. And I'm very glad I didn't because after about 13 months of collecting figures our average daily saving would have been about 44p and a total of £172. At £3k for the battery that's a very long time to get the money back, probably far beyond any warranty or expected life period. The main reason our savings aren't great is because we've always been on Economy 7 or Flux and the differential between night rate charging cost and day rate grid saving isn't as big as on the EV tariffs. I'll give it some thought in future though if we get an EV and heat pump because I'll be trying to stay off the day import rate. But the maximum saving I can make will still only be day rate minus night rate times useable kWh (4.75 as we only discharge down to 5%). Even if it's utilised 100% every day saving me 22p per kWh that's still only about £1.10 per day and about £400 per year. And it just won't be utilised much in the summer with little heating on as we found this year that our one battery lasted until the night rate started pretty often.
Battery prices have come down but my calculations still give a ROI of 5 years at best. This is with the saving from winter off peak electric as you have done PLUS capturing solar gen in summer and discharging at peak Flex rate instead of the day rate. All depends on the off peak/peak price differential, inverter charge rates, etc. it’s not great. My December generation was 143kWh on 1660kWh of consumption (852kWh on the ASHP). Generation was significantly down on November (282kWh) but consumption was up (November was 1402kWh of which 825kWh was the heat pump). But despite the higher consumption, as Agile prices were lower we paid £55 less for our December electricity than we did for November. Plus the £50 DFS saving meant a comparatively cheap month
Yeah, I'm not currently accounting for extra income that I could get in the Summer from the extra battery capacity, but I'll be adding that in when I do the full calculation in the Spring. If battery prices continue to fall that'll help too.
In order to maximise your off peak savings potential, it might be worth thinking about storage heaters running on off peak instead of extra battery storage for the colder months. Second hand units are very cheap or even free, require no maintenance, are easy to install and would reduce your peak rate usage.
But storage heaters are only 100% efficient whereas heat pumps are 300+% efficient. So running the heat pumps on peak power works out about the same cost as running storage heaters using off-peak power, or often slightly cheaper. That's why heat pumps are so good.
@@hightechpete it's a fair suggestion, don't get me wrong. And if the peak/off-peak ratio was different it would be a different story. But running heat pumps from off-peak power stored in a battery really is unbeatable right now.
@@analogueavenue Storage heaters have had bad press, I'm a big fan and can't resist promoting them. In terms of running costs they're equivalent to heat pumps but have virtually zero maintanance costs.
@@analogueavenue I think that's a good idea, I'm considering diverting all my excess solar panel power to the off peak circuit during the colder months, the problem is that on a clear midwinter day I'll only get around 5kwh which equates to a 60p saving on my 12p off peak rate and I wonder whether it's worth the effort. The government subsidy does not apply to an air to air heat pump but with the current pricing structure I'm probably better off with my storage heaters anyway. I can't complain, £1800 pa FIT payments and total energy bill of £1200, just hoping that the economy7 rate persists.
The problem with the A2A dehumidifying is that it cools the house. I did try it last year but it was too cold! The dehumidifiers have the advantage that they heat a little bit at the same time.
Tim, as a suggestion rather than buy additional batteries why not consider switching to eon next? You can then have 7 hours of off-peak electric for the 8.9p per kWh. I’m assuming your heating comes on before 7am so you could heat the house straight from the grid then have a full battery to get you through the day. Their off peak is midnight to 7am.
We start the heating at 6am. One hour of off-peak won't make much difference at this time of year really, and we'd still run out of battery long before the end of the day even if we heated the house all through the night on a lot of days. If we get onto Intelligent Octopus Go their off-peak rate is 7.5 p/kWh and has extra off-peak periods during the day too, so I'd rather do that, I think.
Hi Tim, thanks for your really helpful videos. Re Octopus Intelligent Go extra hours outside the 2330-0530hrs, is there a way of knowing ahead of time when the extra hours will be or are they random?
@@tamsineh no, I think you only find out when you plug your car in to charge and the extra periods appear. I've not experienced it myself, however, so I don't know for sure, I'm afraid. Hopefully one day I'll be able to make a video about it but I suspect it won't be until next Winter.
I share your disappointment. Only 40.9kWh in Fife (6.3kW array) for December. So many rainy, grey days coupled with short days and low sun at this time of year. Hopefully, January’s results will be better.
@@joeerskine4858That definitely helps in Winter having only south facing panels, whereas my setup is split into 5 panels on the east, 4 on the south and 6 on the west.
I've added an extra bit to my Octopus analysis spreadsheet so I can probably make that available at some point. It'd need a bit of tidying up first, mind. If I can find a spare slot I'll see if I can record a video explaining it.
Remember the smaller and older GE batteries generally limited to 2600w output. Not so with the 9.5kwh one of course. Did you extra battery calculations factor in it'd still cost you 80+p per day (for the 9.5kwh) to fill it up off peak? Assume it did.
The calculation accounts for peak and off-peak prices, so the saving is based on the difference. If you have multiple batteries connected to the same inverter (as we already do) it's usually the inverter that limits the charge rate, rather than the individual batteries. For example, we have a 9.5 and a 5.2 connected to a hybrid 5 kW Gen 2 inverter, and that charges at 3.6 kW. Adding an extra 5.2 on that system will still result in a total charge rate of 3.6 kW since the inverter is already maxed out. It just gets shared out between the three batteries (so each one receives well below its own individual charge rate).
@@TimAndKatsGreenWalk I got my GE system in mid '22 and the we have the Gen 1 5k inverter and the 8.2kwh battery. Both limited to 2600w. Toyed with another 5kwh battery, but not particularly cost effective. Good to hear the Axel DFS working.
I'm interested to see how the last graph works out. It may also be looking at extra DFS for a year or 2 if it is close to break even. Also are there any second hand Givenergy batteries knocking around from people upgrading to the AIO.
Tim how do you monitor all the different electricity demands within your house (towel rails, cooker, heat pump etc). I expect someone has already asked this , apologies, but there are too many videos and too many comments for me to find the answer.
No worries. For the heat pump, dehumidifiers, and towel rails we have them plugged into smart plugs that measure the energy usage. The hot water is controlled by an eddi so that also tells me how much energy we used for that. The EV charger is a similar story as that tracks the amount charged. We don't have anything on the cooker though, that falls under the "remainder" category, i.e. general house base load.
I save £100 per year using a air to water heat pump just cancelling the standing charge for gas. If you charge a 250l hot water cylinder off peak to 70oC using a Vaillant air source heat pump it would cost 36p per day @9p kwh or £11.16 per month for DHW (Direct Hot Water) during winter and cost nothing in Springs, Summer and Autumn with a 6,8kwp array and 15kwhr battery system. Surely that is a better ROI than using 4.8kwh battery or more?
@@TimAndKatsGreenWalk Not seen all your content what do you use for DHW (Hot Water)? Just seen your footage. An immersion heater is a very inefficient and expensive way to heat water unless surplus electrical energy from solar is used (Spring, Summer and Autumn). I'd go for an air source cylinder in this scenario. But overall I wouldn't choose an A2A over an integrated air to water heat pump set up. But I might consider adding a couple of A2A units for extra cooling in the summer.
@@DMFPERFORMANCE go watch my previous video, I cover a lot of this stuff in that (I have a hot water playlist too). Immersion using cheap overnight power still works out cheaper than gas, but really, watch my previous video.
Advice please. I need 15kwh a day to power for power outages that can last from a couple hours to a few days. I'm in Michigan so my solar hours is 4.48, 1,278 Kwh per 1Kw, says need 4.24 Kwh array I'm looking at a 400w, 36v panel, says output DC 39V, 10.25a max, transfer efficiency greater or equal to 21% A MPPT Charge controller of 100a, says 12/24/36/48v Auto, Max Input 100v. Max charging current 100a. Max Input volts of panels should be 30v-45v (for 24v battery). Max Input power of panels should be 2000w. Output voltage DC5v/1.5a Inverter of 4000w/8000w Peak, Pure Sine Wave Power Inverter, DC24v-AC110 And Battery is LiTime 24v 100Ah, LifeP04 Lithium Ion, Build-in 100a BMS, 2,560 Wh Energy. Up to 4P2S (don't know what that means) 48v battery 400Ah of 20.48 Kwh It's only 1000sq' apartment, 2bd/2ba. Old Kenmore Fridge, elec range, micro, dishwasher (which I'd forgo during an outage), a couple computers and tvs, wifi, lights, a mini-fridge, that's about it. No washer/dryer and if I did use my hair dryer, it's 5 mins or less, but I don't use it every day (and my housemate is bald). For obvs. reasons I wanna keep the heat on and the fridge. We'd unplug things we don't need for a few days, but I'll stick with what we've averaged over the last year anyway just to be safe at the 15Kwh a day. Also, if I'm not mistaken this setup had a good amount of room to grow? The 400w is just one panel so I can add another 400w, etc. and the other components I believe have a lot of room yet? I'm hoping to build a near-off grid home in the next few years, so I'll take it with me as obvs. I can't install anything permanent here. Am I on the right track here? Too much, too little, just right? Any part of this not work with another or could be downgraded or done better/easier/cheaper? Any part of it I don't need? Anything I do that's not here? What I have here is about $1,450. If I'm WAY off on what I think I need, please don't make fun of me. lol I'm learning and this is all new to me, but I'll get it. It's looking less like greek every day. Thanks for your time!
This probably isn't the best place to ask those questions. Yes, steep learning curve and costly if you get it wrong. From what you've said above, it looks like a DIY installation, whereas this channel is an off the shelf, professionally installed system. There are a few forums that would probably be more helpful to you. ps 4p2s is a description of how cells are connected to make a battery pack, 4 in parallel and 2 in series, so if your cells are (for instance) 18650 Li-Ion at 4.2v then the 2s would give you 8.4v.
I'm not a professional so I can't offer advice on specific equipment as I only have experience of my own system, which is a permanent install, not something I'd take away with me. But here are my basic rules of thumb: Get a battery about the same size as your current daily usage (15 kWh in your case) Get as many panels installed up front as you can fit and afford as adding extras later is costly and disruptive (extra scaffolding etc.) But it sounds like you're not going down the route of a professional install on your roof, so I can't help with that, I'm afraid. This is my system, btw: czcams.com/video/m1mIljYtFds/video.htmlsi=jo1uUsLVZYeh6rsa
If you're planning on taking any equipment with you you might find a portable system is more appropriate, something like this: www.ecoflow.com/us/delta-pro-portable-power-station You can add solar panels too: us.ecoflow.com/products/delta-pro-400w-portable-solar-panel?variant=39746297921609
Hi Tim, do you have any idea whether you are better off with Axel or Octoplus for DFS? Also, do you have any tips for making the most out of these sessions for those with a GivEnergy system. Thanks.
Good question. Axel is best for those who want to just leave it to do its own thing, whereas Octopus needs more manual intervention albeit with slightly higher payback. I went with Axle because I'm lazy!
No, it's the same method as before. We're just on a different tariff (Go) so the off-peak and day rates are different, but it all goes through the same spreadsheet as before.
Sure. The EV charger tells me how much goes into the car. We have a myenergi eddi that manages our hot water (basically just using it as a timer, really) and that tells me how much energy the hot water uses. Then the towel rails, A2A units, and dehumidifiers are plugged into smart plugs (GivEnergy) which have an energy monitoring function. So the data needs a bit of collating from the various sources but it works pretty well.
Yeah, I put up a text box to that effect (forgot to mention it during recording). If we can get onto Intelligent Octopus Go we'd be better able to charge any extra capacity.
Hi Tim. Where could I get a copy of that spreadsheet? I'm imminently getting a solar/battery set up at the beginning of Feb and would love to keep track of the data.
Do you mean this one? czcams.com/video/5FwjccO2bZc/video.htmlsi=ASXFpvNTQykfW8Z- The link is in the description of that video. Although that only covers the Octopus data. By the way, you can get some very good charts using the GivEnergy app or web portal too, so check those out as you might not need to use a spreadsheet for most stuff.
@@TimAndKatsGreenWalk I don't see the link in the description. The link you pasted just brings up this video again. I've not got my Givenergy system installed yet but thanks for the info. I was just hoping to enter my historic usage into a spreadsheet pre solar for comparison purposes.
@@clintcabral196 it's a different video I linked to, it's not the same one. The link to the spreadsheet is in the description of the video I linked (I checked it and it's definitely the right one, it's doesn't link back to this video).
I’m not convinced that you will be able to get a vat free battery. I suspect that it’s installers who can help you benefit. Compare it to solar…. My install was VAT free but I can’t go to the shops and buy a vat free solar panel. (It’s a shame as I’m considering an extra battery myself.)
December is the first month of summer here in Adelaide South Australia. However it has been a bit cloudy. From the 6.3kw north facing system on the house, generated 920 kwh. From the east west facing 6.5kw system on the shed, generated 995 kwh.
Total generation from both systems is 1.91 mwh for December. The total generation for 2023 is 15.11 mwh considering the the system on the shed was only installed at the end of April 2023.
Can you send some our way, please!
@@TimAndKatsGreenWalk might have to move the uk a bit closer to the equator.
@@Ryanhothersall just send a cable through the middle 😉
Interesting plan. I was actually looking at the other way around of adding more solar panels rather than battery. While they will only help a little bit in winter the amount of extra power sold during the other 8-9 months of the year should help to offset the winter costs.
Well, that's another story that I'm planning on covering at some point soon too 😉
It might be worth seeing how much you can top up your batteries during the day (when your EV is at home) when you get onto the Intelligent Octopus Go tariff before you decide to invest in another battery......We have always been offered the same regular daytime additional slots (10-30 -12 and 2-30 -4) and our evening charge always starts well before 11-30pm (often from 8-30pm onwards) which is great for topping up the batteries if needed.
I agree, I was surprised just how many extra hours you get especially over the Christmas and new year holidays. It would also be cheaper to change to a compatible charger if that is required.
Yes, indeed, that's worth considering but difficult to calculate when I don't have any reliable data on it. Might have to be a bit of finger in the air kinda thing.
We hit 96.4kWh. It’s our first December with solar so I don’t have anything to compare with. It seemed dark but on the plus side less cold which kept our heating demand lower than last year. Can’t wait for less gloomy days!
Yeah, I think that's a fair assessment. We had lower heating than expected so probably better off overall. But still, a bit more sun would be nice.
Really like your videos.
I've got 4kW of solar with enphase edge inverters. Here are my Dec generations for the last 11 years:-
2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023
Dec 130.2 163.7 98.4 134.1 127.8 124.0 148.8 114.7 80.6 127.1 85.8
Dec 2023 was the second worst Dec within that time period.
What was also interesting was that there were only 8 days in that month when my panels produced over 3.5kWh, so 23 days when every drop of generation was being consumed by the house's 'base' load (of 300w) and therefore no excess. 😞
Yup, I've had no excess at all recently, especially with the A2A system running there's no chance!
You need to consider the charge rate and time alongside batteries as at some point you can’t charge them up in the off peak period. We hit that limit so can’t add more battery without larger inverter capacity.
Yeah, I added a text box to that effect as I forgot to mention it during recording. If we get onto Intelligent Go that would give us enough time, even with some extra capacity, so hopefully we can achieve that in time for next Winter.
And max discharge rate
I’ve been thinking about doing the same, I have a moixa 4.8 kWh battery and am considering adding the same again or a 9.6 unit, this video I proving extremely helpful with those considerations , many thanks.
No problem. Hopefully I'll have a good answer once I've got a full Winter's worth of data.
It was my worst December since panels installed in 2014 so you aren’t alone!
Well, that's comforting to a degree.
Ditto for us, Spalding Lincs since 2012 on our original array south facing. Combined array (new plus original) was 5.5kw 105.3. Thank goodness for the Powerwall 2 capacity and the Intelligent Go six hour cheap rate window.
Hopefully the rest of the year will compensate.
I generated 20% less this December compared to December 2022. On the plus side the pond and water butts have never been so full!
Ha! Well, good to look on the bright side.
December is the first time we have generated less than the installer predicted 77.73kwh generated, predicted was 114 kwh
It seems everyone has been in the same boat, so at least it's consistent!
Purely from my perception as to how often it was gloomy and raining it felt like December was rubbish. We got 74kWh. Just checked and the previous December was 130kWh. Our consumption from the grid went from 387kWh to 624kWh which might have had something to do with the boiler dying on Christmas Day and needing to run various forms of highly inefficient electric heating for 4 days! Managed to use over 60 kWh on one day!
Somewhat frustrating when we got it fixed that the problem was the outflow from the boiler (condensing pipe?) was backed up because the drains were blocked. Had I known (I'm not a plumber, I would never have figured it out) I could have fixed it within 10 minutes by unblocking the drain.
Live and learn....
Gah! How annoying. I'm glad you got it fixed in the end and at least you know what to look out for now.
We generated 110kwh in our first ever December, 16 x 385w panels. Pure South facing, in Yorkshire, no shading, using micro inverters. Quite happy with that after reading others numbers in the comments.
Not bad considering. I'd be pleased with that.
Thanks for this Tim, really helpful to see that you were also way low compared to the PVGIS tool, we were too and I was wondering if it was something specific to our installation but clearly not. Tbh, recent savings sessions have more than made up for the shortfall.
Yeah, seems like a lot of folks had a rubbish December.
Good update Tim 😊. We installed 3.8kw solar panels in Dec and already have an 8.2GE battery. I was genuinely surprised to see any solar at all in Dec, but my naivety showing there! Overall though our solar data is fairly similar, so I’ll be paying attention to your analysis over the next few months.
On an aside, I had the first nearly totally clear sunny day today and generated 9kwh. Happy with that and even treated the EV to around 7%!! That’s the dream!
Wow 9 kWh! 4.3 kWh was our maximum over the last month, you did well there. 2.8 kWh today.
We produced 3.6kWh today and 11kWh yesterday. So far Jan 2024 is brighter than Jan 2023. Lets hope for a cool bright first quarter,
I notice our unit prices are different. Switched to Octopus Go from Octopus Flux in mid October via a telephone call with Octopus. Unit price 00:00-04:30 7.5p other times 40.9p. Used 109 peak units 22 of those were for recharging the batteries after a saving session. ASHP uses 1.5 as much power when outside temperature is negative celsius compared to average of 4-7 celsius so had to import at peak rate on four days in December. Only participated in the last three saving sessions which brought the bill from Octopus down from £99.48 to £41.76
I think different areas of the country get different rates, but I'm surprised your off-peak is that low. I thought 7.5p was the Intelligent Go rate. Although your day rates is a lot higher. Weird. Still, as long as you can use mostly off-peak it's all good!
Your point about ability to fully charge during off peak periods is a good one. This charge capacity is a combination of both inverter and battery. More by luck than anything else, our 5.5kW inverter and x4 5.32kWh batteries seem a pretty good match for our peak winter use and the 3hr Octopus Flux window, but that wasn’t due to any real calculation on my part 🤦♂️
Ha! Well, I'm glad it worked out for you. If we can get onto Intelligent Go then we should have no problem charging an extra battery too, so with any luck we can achieve that by next Winter.
Tim Interesting data I look forward to the spring to see how much peak you use. Great news on the no vat on additional batteries. Having the extra battery may in the milder winter months really save you cash maybe with some extra panels as well
Extra panels is definitely something I'm considering too. More on that in a future video, however...
My set up in St Neots generated 140 kWh in December. A southfacing, 6.4 array and a 5kW inverter.
That's decent. I think in Winter South facing makes a big difference.
My 7.56kWh Solar PV also split over an E/W roof only gave 64kWh. It is the worst December as usually around 100kWh. Overall 2023 was down on our average. Our ASHP for DHW and Heating used 517.72kWh for our 5 bed detached 1973 house.
I'm getting a lot of other reports that December was bad so it seems we're not alone.
Hi Tim, December was dismal. I’m not far from you and mine produced less than half of 2022 and 2021 levels. Although unlikely to hugely affect production, I’m thinking about having the panels cleaned for the first time in March. Rob
Seems like a common story this December. I'm sure a bit of a clean couldn't hurt but as you say it might only make a marginal difference.
I've had my panels for 11 years. Year before last I got my window cleaner to use that pure water cleaning stuff on 8 of my panels. I have Enphase Edge inverters so can see what each panel produces individually each day. I took some readings of all panels before the cleaning picking a couple of 'good' days and a couple of 'poor' days, then did the same after the the 8 were cleaned.
IF there was any improvement, I couldn't detect it between the pre and post cleaning figures. So, for 10 years, cleaning didn't give any perceivable improvement, so I'll just leave them.
I do from time to time do a check of the panels (production) to confirm all 16 are still doing well, even though I get email notifications of any issues that arise from Enphase.
@@cgreene3745 that is fascinating, thanks for sharing your experiences. My father in law has never cleaned his panels in 12 years and has also not noticed any change over that time.
We're also in sunny Gloucester and generated a monumental 77kWh from our 7.6kW EW array.
My suspicion is, you'll find extra storage isn't worth it, even if you could charge overnight, which you can't on Go as the charging period isn't long enough.
I'm assuming you're hoping the GE charger will be compatible with IOG soon, in which case don't forget to use the different prices in your calculations.
Yes, indeed, we would need to get onto IOG for extra battery to be worthwhile. It'll certainly be a close run thing based on a back of the envelope calculation I've done. There are a few other benefits to more storage too though, over and above the reduction in heating costs, so that might swing it.
The cloudy December was also milder, so swings and roundabouts if you use electric heating/weather compensation.
That is true.
This will be a quick one!! I've decided to get an extra battery in Feb when the VAT rules change. Extra solar panels may come later. Went onto Intelligent Octopus Go last month so now get a longer night rate tariff at 7p/kW/hr.
Nice.
Tim, thanks for another interesting video. 2 questions.
1. I have an air to water heat pump and I run this 24/7 working on weather compensation. I have a daytime temperature set at 20C with night-time set back temperature of 17C. For comparison, how do you run your air to air system?
2. I have two GE 8.2 kWh batteries daisy-chained to a GE AC coupled 3.0 inverter. I am on Cosy tariff and, in December, my batteries lasted through the day on the two 3 hr cheaper slots. I would never manage this with one cheaper and longer overnight slot - I can't get enough juice into the batteries! However with temperatures dropping, even my batteries will probably run dry before reaching the next cheaper slot. An extra battery wouldn't help unless I also got another inverter (which I believe that GE do not support). I also worry that we are basing ROI on current tariffs and National Grid policies. This scenario will likely change in the future, perhaps with electricity usage controlled more centrally. And batteries are expensive. I will be interested to see your financial breakdown for an extra battery. My gut feel is that it wouldn't be viable and I would be better off getting as many panels on my roof as possible. Perhaps the National Grid should pay for out batteries as we should be helping the grid with national distribution of electricity!
Thanks Rob.
We run our A2A units from 6am to 20:30 with the temperature set to 18 in the less used rooms and 19/20 in the lounge and office where we spend most time. I manually adjust as required during the day if we need a little boost. The single longer overnight period has the advantage that it's a lot cheaper than the cosy off-peak rate so we can use that to charge our EV and heat our water at that time too, so that works well for us. There are other advantages of more battery capacity over and above helping to cover the heating (and assuming we can get onto Intelligent Octopus Go which has six hours of overnight rate), so I'll be discussing all of that in the Spring when I present my analysis. In the long run prices will continue to go up, don't bank on them coming back down to the level they were a couple of years ago. They may temporarily drop for a time but they'll absolutely go back up more over the long run.
111kwh from a 7.4KW array. This is my first year. Installed in November 23
That's a good sized array. You should get some great generation in the Summer.
If you have "spare" battery capacity you can export power in DFS or agile greatly increasing your pay-back.
Yes, that is one additional benefit that's worth factoring in. That might be what puts it over the edge.
My December solar at 74% of expected, and 23.25% lower than previous year.
Looks like everyone is in the same boat.
Yup, getting lots of similar comments! Let's hope January isn't so bad.
December 2023 was very dull across the UK.
The spreadsheet I whack a few figures in each day calculates how much we'd save with a 2nd 5kWh battery. Our installer originally priced up 2 but I didn't want to commit to that at the time as the option was always there to add it later. And I'm very glad I didn't because after about 13 months of collecting figures our average daily saving would have been about 44p and a total of £172. At £3k for the battery that's a very long time to get the money back, probably far beyond any warranty or expected life period. The main reason our savings aren't great is because we've always been on Economy 7 or Flux and the differential between night rate charging cost and day rate grid saving isn't as big as on the EV tariffs.
I'll give it some thought in future though if we get an EV and heat pump because I'll be trying to stay off the day import rate. But the maximum saving I can make will still only be day rate minus night rate times useable kWh (4.75 as we only discharge down to 5%). Even if it's utilised 100% every day saving me 22p per kWh that's still only about £1.10 per day and about £400 per year. And it just won't be utilised much in the summer with little heating on as we found this year that our one battery lasted until the night rate started pretty often.
It's definitely good to keep track of these things. In the Spring I'll reveal my conclusions.
Battery prices have come down but my calculations still give a ROI of 5 years at best. This is with the saving from winter off peak electric as you have done PLUS capturing solar gen in summer and discharging at peak Flex rate instead of the day rate.
All depends on the off peak/peak price differential, inverter charge rates, etc. it’s not great.
My December generation was 143kWh on 1660kWh of consumption (852kWh on the ASHP). Generation was significantly down on November (282kWh) but consumption was up (November was 1402kWh of which 825kWh was the heat pump).
But despite the higher consumption, as Agile prices were lower we paid £55 less for our December electricity than we did for November. Plus the £50 DFS saving meant a comparatively cheap month
Yeah, I'm not currently accounting for extra income that I could get in the Summer from the extra battery capacity, but I'll be adding that in when I do the full calculation in the Spring. If battery prices continue to fall that'll help too.
1.5/day last year, 0.6 this year.
It’s been my parents worst for 5 years…
The blanket of cloud was bad for solar, good for heat.
Yup, seems that way.
Same on our array was the worst December so far but its wasn't too cold so swings and roundabouts I guess.
Yes, exactly, not all bad.
In order to maximise your off peak savings potential, it might be worth thinking about storage heaters running on off peak instead of extra battery storage for the colder months. Second hand units are very cheap or even free, require no maintenance, are easy to install and would reduce your peak rate usage.
But storage heaters are only 100% efficient whereas heat pumps are 300+% efficient. So running the heat pumps on peak power works out about the same cost as running storage heaters using off-peak power, or often slightly cheaper. That's why heat pumps are so good.
@@TimAndKatsGreenWalk
Didn't think that one through.
@@hightechpete it's a fair suggestion, don't get me wrong. And if the peak/off-peak ratio was different it would be a different story. But running heat pumps from off-peak power stored in a battery really is unbeatable right now.
@@analogueavenue Storage heaters have had bad press, I'm a big fan and can't resist promoting them. In terms of running costs they're equivalent to heat pumps but have virtually zero maintanance costs.
@@analogueavenue I think that's a good idea, I'm considering diverting all my excess solar panel power to the off peak circuit during the colder months, the problem is that on a clear midwinter day I'll only get around 5kwh which equates to a 60p saving on my 12p off peak rate and I wonder whether it's worth the effort. The government subsidy does not apply to an air to air heat pump but with the current pricing structure I'm probably better off with my storage heaters anyway. I can't complain, £1800 pa FIT payments and total energy bill of £1200, just hoping that the economy7 rate persists.
Buy a Grundig Advanced Heat Pump A++ Spin drier . Scrap your dehumidifier. Your air to air H.P. on cooling with low fan will dehumidify.
The problem with the A2A dehumidifying is that it cools the house. I did try it last year but it was too cold! The dehumidifiers have the advantage that they heat a little bit at the same time.
I enjoyed your content
Thank you
Tim, as a suggestion rather than buy additional batteries why not consider switching to eon next? You can then have 7 hours of off-peak electric for the 8.9p per kWh. I’m assuming your heating comes on before 7am so you could heat the house straight from the grid then have a full battery to get you through the day. Their off peak is midnight to 7am.
We start the heating at 6am. One hour of off-peak won't make much difference at this time of year really, and we'd still run out of battery long before the end of the day even if we heated the house all through the night on a lot of days. If we get onto Intelligent Octopus Go their off-peak rate is 7.5 p/kWh and has extra off-peak periods during the day too, so I'd rather do that, I think.
Hi Tim, thanks for your really helpful videos. Re Octopus Intelligent Go extra hours outside the 2330-0530hrs, is there a way of knowing ahead of time when the extra hours will be or are they random?
@@tamsineh no, I think you only find out when you plug your car in to charge and the extra periods appear. I've not experienced it myself, however, so I don't know for sure, I'm afraid. Hopefully one day I'll be able to make a video about it but I suspect it won't be until next Winter.
Only 65 kWh in central Scotland
Enough to boil a kettle at least.
I share your disappointment. Only 40.9kWh in Fife (6.3kW array) for December. So many rainy, grey days coupled with short days and low sun at this time of year. Hopefully, January’s results will be better.
Interestingly I generated 98kwhr from 5.3kw system facing due south in Central Scotland.
@@joeerskine4858That definitely helps in Winter having only south facing panels, whereas my setup is split into 5 panels on the east, 4 on the south and 6 on the west.
I’d love one know how you setup that spreadsheet that shows the peak savings. Looks like a really useful resource.
I've added an extra bit to my Octopus analysis spreadsheet so I can probably make that available at some point. It'd need a bit of tidying up first, mind. If I can find a spare slot I'll see if I can record a video explaining it.
@@TimAndKatsGreenWalk that would be fantastic. Been struggling to work out our ROI with our solar and battery vs our HES loan. Thanks!
Remember the smaller and older GE batteries generally limited to 2600w output.
Not so with the 9.5kwh one of course.
Did you extra battery calculations factor in it'd still cost you 80+p per day (for the 9.5kwh) to fill it up off peak?
Assume it did.
The calculation accounts for peak and off-peak prices, so the saving is based on the difference. If you have multiple batteries connected to the same inverter (as we already do) it's usually the inverter that limits the charge rate, rather than the individual batteries. For example, we have a 9.5 and a 5.2 connected to a hybrid 5 kW Gen 2 inverter, and that charges at 3.6 kW. Adding an extra 5.2 on that system will still result in a total charge rate of 3.6 kW since the inverter is already maxed out. It just gets shared out between the three batteries (so each one receives well below its own individual charge rate).
@@TimAndKatsGreenWalk I got my GE system in mid '22 and the we have the Gen 1 5k inverter and the 8.2kwh battery.
Both limited to 2600w.
Toyed with another 5kwh battery, but not particularly cost effective.
Good to hear the Axel DFS working.
I'm interested to see how the last graph works out. It may also be looking at extra DFS for a year or 2 if it is close to break even. Also are there any second hand Givenergy batteries knocking around from people upgrading to the AIO.
That's a good question, actually. Might be able to pick up a slightly used 5.2 kWh battery for a discount.
Tim how do you monitor all the different electricity demands within your house (towel rails, cooker, heat pump etc). I expect someone has already asked this , apologies, but there are too many videos and too many comments for me to find the answer.
No worries. For the heat pump, dehumidifiers, and towel rails we have them plugged into smart plugs that measure the energy usage. The hot water is controlled by an eddi so that also tells me how much energy we used for that. The EV charger is a similar story as that tracks the amount charged. We don't have anything on the cooker though, that falls under the "remainder" category, i.e. general house base load.
I save £100 per year using a air to water heat pump just cancelling the standing charge for gas. If you charge a 250l hot water cylinder off peak to 70oC using a Vaillant air source heat pump it would cost 36p per day @9p kwh or £11.16 per month for DHW (Direct Hot Water) during winter and cost nothing in Springs, Summer and Autumn with a 6,8kwp array and 15kwhr battery system. Surely that is a better ROI than using 4.8kwh battery or more?
I don't have gas so already save the standing charge. See my other recent videos regarding my hot water situation.
@@TimAndKatsGreenWalk Not seen all your content what do you use for DHW (Hot Water)? Just seen your footage. An immersion heater is a very inefficient and expensive way to heat water unless surplus electrical energy from solar is used (Spring, Summer and Autumn). I'd go for an air source cylinder in this scenario. But overall I wouldn't choose an A2A over an integrated air to water heat pump set up. But I might consider adding a couple of A2A units for extra cooling in the summer.
@@DMFPERFORMANCE go watch my previous video, I cover a lot of this stuff in that (I have a hot water playlist too). Immersion using cheap overnight power still works out cheaper than gas, but really, watch my previous video.
Advice please. I need 15kwh a day to power for power outages that can last from a couple hours to a few days. I'm in Michigan so my solar hours is 4.48, 1,278 Kwh per 1Kw, says need 4.24 Kwh array
I'm looking at a 400w, 36v panel, says output DC 39V, 10.25a max, transfer efficiency greater or equal to 21%
A MPPT Charge controller of 100a, says 12/24/36/48v Auto, Max Input 100v. Max charging current 100a. Max Input volts of panels should be 30v-45v (for 24v battery). Max Input power of panels should be 2000w. Output voltage DC5v/1.5a
Inverter of 4000w/8000w Peak, Pure Sine Wave Power Inverter, DC24v-AC110
And Battery is LiTime 24v 100Ah, LifeP04 Lithium Ion, Build-in 100a BMS, 2,560 Wh Energy. Up to 4P2S (don't know what that means) 48v battery 400Ah of 20.48 Kwh
It's only 1000sq' apartment, 2bd/2ba. Old Kenmore Fridge, elec range, micro, dishwasher (which I'd forgo during an outage), a couple computers and tvs, wifi, lights, a mini-fridge, that's about it. No washer/dryer and if I did use my hair dryer, it's 5 mins or less, but I don't use it every day (and my housemate is bald). For obvs. reasons I wanna keep the heat on and the fridge. We'd unplug things we don't need for a few days, but I'll stick with what we've averaged over the last year anyway just to be safe at the 15Kwh a day. Also, if I'm not mistaken this setup had a good amount of room to grow? The 400w is just one panel so I can add another 400w, etc. and the other components I believe have a lot of room yet? I'm hoping to build a near-off grid home in the next few years, so I'll take it with me as obvs. I can't install anything permanent here.
Am I on the right track here? Too much, too little, just right? Any part of this not work with another or could be downgraded or done better/easier/cheaper? Any part of it I don't need? Anything I do that's not here? What I have here is about $1,450. If I'm WAY off on what I think I need, please don't make fun of me. lol I'm learning and this is all new to me, but I'll get it. It's looking less like greek every day. Thanks for your time!
This probably isn't the best place to ask those questions.
Yes, steep learning curve and costly if you get it wrong. From what you've said above, it looks like a DIY installation, whereas this channel is an off the shelf, professionally installed system.
There are a few forums that would probably be more helpful to you.
ps 4p2s is a description of how cells are connected to make a battery pack, 4 in parallel and 2 in series, so if your cells are (for instance) 18650 Li-Ion at 4.2v then the 2s would give you 8.4v.
I'm not a professional so I can't offer advice on specific equipment as I only have experience of my own system, which is a permanent install, not something I'd take away with me.
But here are my basic rules of thumb:
Get a battery about the same size as your current daily usage (15 kWh in your case)
Get as many panels installed up front as you can fit and afford as adding extras later is costly and disruptive (extra scaffolding etc.)
But it sounds like you're not going down the route of a professional install on your roof, so I can't help with that, I'm afraid.
This is my system, btw:
czcams.com/video/m1mIljYtFds/video.htmlsi=jo1uUsLVZYeh6rsa
If you're planning on taking any equipment with you you might find a portable system is more appropriate, something like this:
www.ecoflow.com/us/delta-pro-portable-power-station
You can add solar panels too:
us.ecoflow.com/products/delta-pro-400w-portable-solar-panel?variant=39746297921609
I looked into the Deltas before and it would double my cost. Seems unnecessary to do that. lol What would I gain?@@TimAndKatsGreenWalk
@Timandkatsgreenwalk And thanks for your answer! I appreciate it!
Hi Tim, do you have any idea whether you are better off with Axel or Octoplus for DFS? Also, do you have any tips for making the most out of these sessions for those with a GivEnergy system. Thanks.
Good question. Axel is best for those who want to just leave it to do its own thing, whereas Octopus needs more manual intervention albeit with slightly higher payback. I went with Axle because I'm lazy!
Tim,
Are you using a different method of calculating costs and savings now that you have switched from Flux for these 'darker' months? (Martin)
No, it's the same method as before. We're just on a different tariff (Go) so the off-peak and day rates are different, but it all goes through the same spreadsheet as before.
Many thanks Tim@@TimAndKatsGreenWalk
May I ask, how did you get the stats to show what consumed what eg, car, hot water, dehumidifier etc? Thanks
Sure. The EV charger tells me how much goes into the car. We have a myenergi eddi that manages our hot water (basically just using it as a timer, really) and that tells me how much energy the hot water uses. Then the towel rails, A2A units, and dehumidifiers are plugged into smart plugs (GivEnergy) which have an energy monitoring function. So the data needs a bit of collating from the various sources but it works pretty well.
battery limit might be how much can you charge overnight.
Yeah, I put up a text box to that effect (forgot to mention it during recording). If we can get onto Intelligent Octopus Go we'd be better able to charge any extra capacity.
Depends if he goes dual inverter (though from memory GE don’t support multiple inverters with a hybrid)
@@JohnR31415 indeed, it's not officially supported. Also it'd be extra cost, but we shall see what the numbers say in Spring.
Hi Tim. Where could I get a copy of that spreadsheet? I'm imminently getting a solar/battery set up at the beginning of Feb and would love to keep track of the data.
Do you mean this one? czcams.com/video/5FwjccO2bZc/video.htmlsi=ASXFpvNTQykfW8Z-
The link is in the description of that video.
Although that only covers the Octopus data. By the way, you can get some very good charts using the GivEnergy app or web portal too, so check those out as you might not need to use a spreadsheet for most stuff.
@@TimAndKatsGreenWalk I don't see the link in the description. The link you pasted just brings up this video again. I've not got my Givenergy system installed yet but thanks for the info. I was just hoping to enter my historic usage into a spreadsheet pre solar for comparison purposes.
@@clintcabral196 it's a different video I linked to, it's not the same one. The link to the spreadsheet is in the description of the video I linked (I checked it and it's definitely the right one, it's doesn't link back to this video).
@@TimAndKatsGreenWalk thanks, it worked that time. Keep the content going. You guys are doing a great job.
@@clintcabral196 cool, glad to hear it. Thanks for the encouraging words, we appreciate it!
I’m not convinced that you will be able to get a vat free battery. I suspect that it’s installers who can help you benefit. Compare it to solar…. My install was VAT free but I can’t go to the shops and buy a vat free solar panel. (It’s a shame as I’m considering an extra battery myself.)
With any luck a bit of competition between installers will ensure at least some of the saving will pass on to the consumer.
We generated 12.1kw in December. Really bad
Oof, yeah, not great.
It was a rubbish, rubbish december.
Sure was.