For people who were saying last summer/autumn wasn't great for Solar, we are now 363 days into our solar journey, with a 6.02kWp solar array with a predicted annual generation of 5,689kWh.
This I took with a pince of salt and assumed if we generated over 5,000kWh I'd be happy as our home use is about 4,500kWh PA,
Well today, day 363 we hit 6,500kWh at noon. currently 14.25% over predicted annual generation
wrighar My solar generation for 2024 was remarkably similar overall to 2023
2023 total generation 10619kWh
2024 total generation 10564kWh
Within this is my FIT array and GivEnergy arrays.
I’ve only had the GivEnergy arrays since 7th January 2023, but have had the FIT since Jan 2016. The FIT data year to year shows quite a bit of annual variation, but again 2024 was similar to 2023:
Date FIT Solar Generation
2016 2,904
2017 2,815
2018 3,211
2019 3,029
2020 3,216
2021 2,945
2022 3,152
2023 3,064
2024 2,977
Not looked at our annual generation but I show 7.3Mw in about 2 years from a 3.25kW array aligned at 165 deg.
Sadly we missed a good Mw before we were registered and about 2.5Mw at 4pkW with Ovo.
My first whole year (2024) was 5278 from 6.24 east/west panels
And that's a wrap.
Year 1 of Solar and battery done:
Zero'd our Electric bill and enough left in the solar kitty (nearly £400) to pay for half our annual gas bill as well.
wrighar I think our yearly bill will be a £200 contribution to the gas bill
With my spattering of different orientation arrays; N, S, E and 11.34 kW array I generated 5,600kWh over the last 12 months. I’ve got 5 panels facing S, 14 east on 2 different levels and 8 North facing all on a 45degree roofs angle. My installer forecast was 6,952 kWh. So way less. I knew it wouldn’t be amazing in terms of total generation (with only 2.1kW of the arrays facing true south) and it looks like I’ve got slightly more shading than expected on the lower eastern array due to next door’s house.
I guess I’ve got the equivalent of a 5kW South facing array in generation terms !
I’m looking at a -£200 pa electricity bill to run the house and car which I’m very happy about. This is enabled by 38kW of battery storage, (10kW export limit) which makes about £1,100 in extra export arbitrage pa alone plus has slashed my peak import electricity down to 0.5%, saving a small fortune. I’m anticipating my peak rate import will decrease to 0.2-0.3% by the end of summer. Gas tracker bill is just under £2,300. So overall utility bills are down to about £2,100pa. I’m really pleased (despite generation being well down on my installers forecast). Getting the solar system and the EV allowing me to get on IOG I’m saving about £7,000pa compared to the std variable rate; £2k savings from the car fuel etc and £5k savings from the Solar and batteries. So at the moment it’s either a 5 year payback or a 7 year payback depending on your point of view, what you measure and if/ when tariffs may change.
Pete UK Not to question your maths but I cant seem to get anywhere near your £7k savings over the last 13 months. Admittedly my second array has only been in since last august but with Gen of 10,032 and an overall electric bill of -£473 from a NET export of 1672kW, actual export earnings £2055, and the value of home use at £1789 (admittedly based on the normal rate of my IOF tariff rather than standard variable so ranged from 22p to 27p) I make my savings about £2262 for March to March.
You mention peak usage and its cost but not sure how you get to £5k savings from your solar & batteries?
I am hoping that our yearly energy bill will be zero but it is too early to be sure yet as we have only had the heat pump since the end of August last year. Assuming Octopus doesn’t change anything, the sun shines, and nothing breaks! This will give rough savings of £3300pa based on heat pump, ev at about 10k miles pa, and running our entire house. No gas or oil fully electric.
Pete UK This is enabled by 38kW of battery storage, (10kW export limit)
This seems to support my thought that more battery beats more panels. Your 'effective' array is approximately double mine but your battery is 7 times mine.
It then dissolves to relative cost/benefit between panels and battery.
As an aside, I am not sure why scaffolding was needed. The men who installed bird netting just used a ladder.
[unknown] As an aside, I am not sure why scaffolding was needed. The men who installed bird netting just used a ladder.
When we had our chimney capped the guy who came to do it ( he looked about 80 years old ) chucked a big ladder against the front of the house, climbed it carrying a roof ladder and a bucket full of tools and was up and gone in half an hour 🤔
Tenkaykev when we had our first 16 panel array fitted the men just used ladders. I did see a house nearby with solar being fitted with ladders but this seems to be the exception nowadays.
The customer pays for it and if the majority of installers now quote with scaffolding there's not much you can do about it. At the end of the day scaffolding is safer.
I'm too on a roughly annual bill running a fully electric house, ASHP, no oil or gas. Export loads in the summer and build up a credit to run the house and heating in the winter. Payback for the solar and batteries will be about 6 years based on saving £3,500 a year on SVR.
@Pete UK I'm interested in the maths of your super-sized 38kWh battery storage and whether you'd have got similar savings with a much reduced battery capacity, and of course lower up front costs.
In the summer the profit is to be had from the differential between export and EV import rates, 15-7p, - 20% round trip conversion losses, so about 6.5p. In the winter you get some of the same with any unused battery capacity plus the electricity saving between day and night rates.
Whenever I've done the modelling I've ended up with paybacks for adding extra battery storage from 10-22 years depending on the scenarios included. If you take a 9.5kWh battery and you are saving 6.5x9.5=62p a day, that's only £225 a year. The winter saving based on using the stored electricity vs importing is more, but its not a lot.
My conclusions were that having some battery storage makes all the difference, as long as you have enough to get through the 4-7pm peak rate period. Beyond that its diminishing returns.
Of course running off overnight cheapest rate electricity is good, but the differential between day and night rate isn't that high and even with heat pumps some day rate import isn't too bad. Tariffs like Cosy and Agile (before the recent increases) made this more workable.
I guess the critical factor will be your inverter charge and discharge rate and whether you can totally fill the batteries in the cheap period. With a 2.6kWh rate on my Gen 1 hybrids that has been the limit.
Solar:
Imported: 18,385kWh @7.18p (av.) = £1,497
Exported: 10,861kWh @15p = -£1,629
Minus savings sessions = -£20
Old bill: 18,000kWh x 0.29p (SVR) = £5,220
New bill = -£150 (April 24–> April 25)
Savings = £5,370
Car fuel savings:
Old petrol bill: £2,000 pa
New bill: £0 pa
Savings = £2,000
I have also tweaked my electric underfloor heating schedules a fair bit since getting the EV so reduced my overall import a bit there as well. And this is purely looking at the SVR comparison. Which I was on pre EV/ solar. Without the solar, I possibly wouldn’t have swapped to Octopus and without the EV I wouldn’t be able to get on IOG.
I can’t fit any more panels on my roof, so that’s not an option. I’ve got 27. It’s full and they aren’t all in the best orientation as it is but I just filled the roof, as incremental cost isn’t that much extra at initial install time, as the scaffolding is there already. Put as many panels up as you can. 100% agree with that.
In my case, having lots of battery storage is really what enabled me to get onto IOG and that has hence given me a net negative bill at present. It may not always be that way as tariffs change. But it enabled me to run all day, all year on 7p electricity. Plus I’ve got flexibility to operate my system differently if things reverse.
Yes, when planning my system, I designed it so that I could fill all 4x 9.5kW batteries in the 6hr window, so chose 2x 5.0 gen3 hybrid inverters. (Actually it was the gen2 initially but the gen3 came out during the installation quote time, so upgraded to that.)
Charge rate on the Gen3 is about 3.3–>3.5kW, so about 1.7kW going into each one of the 4 at the same time while charging, 7kW at max towards the end of charging. The inverter output seems to be the limiting factor in most cases, (also the battery output power) which I think gets missed quite a lot at the design stage, as it isn’t really on anyone’s radar.
From this dual inverter set up my export rate is max 8kW from the batteries during my evening discharge period and 7.2kW normal max draw during the day. I have a 10kW DNO export limit. So it can be higher if I’m generating solar as well. I don’t load shift (except car) and 7.2kW covers the max load during the day. (Don’t draw from the grid when kettles etc are turned on).
At initial design time, export rate was only 4p, so I also wanted the ability to charge the car from my solar generation in the summer or from the stored solar in the batteries when I got home or if I was at home. Rather than let it export at 4p. That changed later though.
At the time I was using a lot of electricity and at 38p on the OVO SVR I had bills of £6,500pa just for my electricity!
At the time I thought 38kW storage wouldn’t be enough to last a winters day and I’d probably be importing 20kWh extra at peak on the coldest days !
Turns out, I mis-calculated that, as I hadn’t allowed for the fact that I’d be using electricity during the off peak period already. I can actually last the whole day in winter on battery power only.
Doing a simple calculation of adding one battery and seeing what extra export you’ll get just from that one extra battery at your current average rate isn’t that simple for a proper payback comparison. Sometimes you have to compare apples with oranges, because we’ll now be dealing with the cost of oranges not the cost of apples any more, which is counter intuitive. 😂
I’ll explain why….
The key thinking (and calcs) should be this: If I add an extra battery, will I be able to get onto the absolute cheapest import tariff, (Intelligent Octopus go for example), last the whole day on battery and get almost all my electricity at 7p on average? If it does then you’re looking at ALL your import cost decreasing from whatever it is now, 15p, 12p, whatever, down to 7p. So whatever you paid for your total import over the last 12 months. Say £2,000 at 14p average cost, just as an example; That now becomes £1,000 for ALL of your import costs. Half ! Batteries, home, car, everything. So adding just that one battery may open up huge savings - 50%, maybe more for some! Then there is the extra export opportunities you mentioned and did your calcs on. So on the face of it payback may not look great initially. But if it unlocks IOG for you then it changes everything quite significantly.
Of course, as we know lots of things change and there are a lot of moving parts and it may work extremely well for some saving thousands but for others it doesn’t look as amazing or work out that way due to existing limitations. So adding a battery and using a simple calculation it may look like it’s £200 a year saving from import/export. In reality it might be £1,200 or more a year in savings. Plus you likely have cut out all those times you had to import at peak time in the past in winter or whenever. They add up but maybe now they have all gone away.
I think round trip should be about 10% for import then export and 5% for solar generation to export for a hybrid, no? 5% for each conversion?
I’ve still got a gas bill, house isn’t suitable for a HP. But I’m really happy with my system and it’s savings.
By the way, I don’t disagree about diminishing returns. There is a point you get to and that is absolutely true. I think you’re at that point. I may of tripped over it.
The main point I was trying to make is; If an extra battery unlocks a way cheaper average import rate to you it’s a no-brainer. If not, yes, I agree it’s marginal and or diminishing returns.
I perhaps do have slightly more battery storage than I initially calculated I needed but it’s there now and with future degradation, maybe in 10 years time I’ll have the perfect capacity 😂. I’ve got a negative electricity bill (for now), goal achieved. Due to necessity (house size, poor roof orientation for solar, poor wall insulation, etc) I had to take a different route to others to achieve that.
There are so many moving parts to this that it’s a
nightmare trying to calculate anything, particularly at the planning stage. Maybe the 20% VAT exemption will go away in the future for example? Electricity prices could be double in 5, 10 years. What were they 10 years ago? No idea. This could all change things from being diminishing returns today to “bloody hell, that extra battery was a bargain back then”. Or not.
I think those that can get to a zero (or negative) bill have done extremely well. And it’s a pretty good feeling that you can’t really put into pound notes.
You can look at your system as effectively being an index linked tax free investment.
You have invested to unburdened yourself from the uncertainty of huge(?) unknown bills in the future. Which is nice.
Roy124 As an aside, I am not sure why scaffolding was needed. The men who installed bird netting just used a ladder.
Working at Height regulations mandates scaffolding for anything other than low-risk, short duration work. Both the netting and the chimney work mentioned are not "low-risk or short duration".
If people choose to work in contravention of HSE guidance then best of luck to them when they have an accident as they'll get bugger all compensation (employers insurance invalidated) unless they're forced to work that way by an employer & even then best of luck as it'll require a prosecution of the employer which happens rarely and can take a decade or more to conclude.
Working at Height regs have saved thousands of lives. Only cowboys ignore them.
[unknown] thank you. Reminds me of a situation at work in the 70s. Two riggers on the site outside my office window were fitting roofing bars to a frame building. One was standing on the top frame. Them second man was hefting the metal bars straight up.
The bars stopped their ascent as they reached the rigger who simply took hold and laid innon in place. No hard hats, no harnesses, no gloves.
I went round to see the site manager. His cabin was at the far end of a hard hat area, no entry without permission.
@Pete UK Imported: 18,385kWh @7.18p (av.) = £1,497
Exported: 10,861kWh @15p = -£1,629
Minus savings sessions = -£20Old bill: 18,000kWh x 0.29p (SVR) = £5,220
New bill = -£150 (April 24–> April 25)Savings = £5,370
Interesting, thanks for the breakdown. It was IOG and the 15p fixed export that really was the breakthrough for you, that unlocked being able to use your battery capacity far more than you anticipated you would have done.
I have two Gen 1 5kW inverters so am limited to about 2.4kWh charge rate. A 9.5 and a 5.2 (4.2 usable) battery. At the time Gen 2 was out but very short of stock in the UK after Covid supply chain issues, and I knew no better otherwise I would have held out for the Gen 2. As it was the Gen 3 came out not long after and my less than a year old Gen 1's were effectively end of life. Annoying but there we are.
Not disputing your figures Pete, but is your consumption really 18,000kWh a year? Seems very high, even allowing for an EV and electric UFH. What is your annual generation, something like 5-6000kWh?
Round trip losses are somewhere in the range 10-20%, its about 5-6% AC to DC and back again, and 3-5% inverter losses. 20% is at the high end, just makes the maths easy. 15% more a realistic mid point.
My own 2024 figures for comparison:
Import 9100kWh @ average 12.47p = £1,135 (Octopus Agile all year)
Export 7600kWh @ 15p = -£1,140
Net -£5 minus £80 of DFS saving sessions for winter 23/24. 24/25 is more like £20
Generation 10,600kWh (44 panels in total, 14.4kW)
Consumption 7000kWh total of which 4300kWh was the heat pump
My comparison is therefore 7000kWh on SVR would have been £3000, so £3005 saving.
My batteries are nowhere near enough to run the heat pump on in winter, the heat pump alone is 20-40kWh a day, but can peak to about 100kWh on really cold days. Hence for me tariffs like Agile or Cosy have worked well, enabling within-day charging
Pete UK I get what you say, and with your usage being higher than your gen the extra battery storage combined with IOG's 7p rate has helped immensely, but I find the overall "savings" calc a little bit too simplistic. I think your apples and oranges have a few bananas in the mix 🙂
My reasoning is that without the solar/battery setup you wouldn't be importing 18mW and exporting 10mW, from your figures it looks closer to 13mW old school import. With your amount of churn on the batteries I wouldn't underestimate the losses either as running all that kit and the conversion losses all mounts up. Its pretty hard with GivMaths to actually get a true figure on your house consumption but I bet its lower than you think as all this focus on energy systems has probably meant you have made savings on your previous usage pattern.
Also your cars 2.86mW must be considered in the equation as that's not home use. Maybe you would have still gone on a car tariff without batteries which would change the figures to use for your calcs.
I am not sure what your car app calcs are doing as £9 on electric is one hell of a cheap rate 🙂
Dont get me wrong, your system is giving you the ability to maximize the 7p IOG rate as well as sell a chunk back at 15p to help with savings so you should rightfully be be chuffed, just not, in my opinion, £7k worth of chuffed 🙂
Yeah, I see what I’ve done. I’ve included the car savings twice. Whoops. Once in the overall calcs and then added them again from the car app.
Maybe it’s too simplistic but I’ve set the car app charing at home rate to zero for my charging costs because I’m not actually paying anything to run it, makes it easier to calculate savings (obviously it didn’t 🙄) The £9 is from a supercharger. I wanted the car app to represent what I actually paid to run it, as the non-home charging isn’t included in my utility bill total obviously. I think that’s probably why I accidentally added the car savings twice.
My electric usage is down a fair bit now after tuning our many electric underfloor heating mats (basically turning some of them off completely and turning the rest down significantly; my home usage is down to about 13,200kWh now. But it was 18,000pa from my last OVO bill. Pre-solar, we did go on the OVO EV tariff when it was launched but the savings were only for the car, not the whole house. And we’re using over 25% less for the car now, as we no longer have to do a school run. Car used to consume about 4,000kWh for 14,000 miles pa. Now it’s under 3,000kWh.
Import last 12 months was 18,385 and export was 10,860. So difference is 7,525.
I generated about 5,650 kWh last year. So plus 7,525 is a usage of 13,175. Significantly lower than before.
Thats about £4,000 @29p SVR with the standing charge added in. I’m certain I’m still saving more with an EV. No tax (for one more year), no servicing, parts, etc.
I’m sure that’s easily £1,000 compared to a fossil fueled car. So I stand by the overall £5,000 figure but the £7k was in error, thanks for highlighting that.
Like I said before, a lot depends on what you include in the savings calcs. I’m effectively consuming 13,200kWh pa and my bill is -£150 running the house and an EV. So I’m still very pleased with that.
Could I get my bill down below zero with less batteries and on agile? In my case I don’t think so. Maybe I could(?). It’s hard to know for sure.
I could reduce it of course and I’d have paid out far less for the install but overall (as long as it keeps working) I think I’ll save more in the long run despite the higher initial outlay.
Also, I can’t get on agile due to the balancer software running on my dual inverters. I need a hybrid EMS fitted before I can. So for now I don’t have the opportunity to try it out as the hybrid EMS doesn’t exist yet.
Pete UK As was said, GivMaths is extremely difficult to get right, and when you throw in issues with the portal not understanding muti-inverter setups and screwing the numbers up, it makes it even harder.
As you say, you’ve got a substantial saving, you’re paying less than you were before, its towards zero and an EV is included, so overall all good.
Picking up on one point though
Pete UK Also, I can’t get on agile due to the balancer software running on my dual inverters
You can get Agile, what tariff you are on is not related to how you control your inverters. The difficulty is how you control your inverters with the tariff. In reality Agile is no different to IOG, there are cheap periods to charge up in, there are more expensive periods to be in Eco mode in, and there are bits in between where you might want to export to get ready for the next cheap period.
To get the best use of Agile you need some form of management software to control your inverters. You can do it manually, there are definitely people on here that do that (look at the cheapest slots for the next night and program the inverter), or you use something like My Energy Optimiser, WonderWatt or Predbat to program the charging/discharging and they may/may not work so well with the inverter balancer. Certainly Predbat and Wonderwatt program slot 1 of the inverter so no real difference to what you would do with IOG.
But at the moment I wouldn’t recommend Agile. Even now in late April when you’d think electricity demand would have fallen, Agile overnight rates are still around 12-15p. Any of the EV tariffs is cheaper than this.
geoffreycoan But at the moment I wouldn’t recommend Agile. Even now in late April when you’d think electricity demand would have fallen, Agile overnight rates are still around 12-15p. Any of the EV tariffs is cheaper than this.
The one caveat to that is if your battery doesn't carry you through and you end up using some peak grid. Obviously depending how much peak can make Agile cheaper than the other tariffs as my analysis has shown me over the year. Only in November, January and February would I be better off on Cosy. Now we get plenty of solar, long charging days (and shorter nights) I'm hardly using any grid at all except when Agile prices plunge so my average Agile rate is beating all the other rates (with the possible exception of the Go off-peak rate).
Windy Miller yes you need your battery to be able to take you through the peak with Agile, otherwise it can get a bit rubbish. I went most of winter 24 with just a single 5.2kWh battery (4.2 usable) on Agile, and with the heat pump it was tight, ending up with usually a bit of peak importing.
Predbat does a compare of tariffs every night, and pretty consistently Cosy and Agile are about the same, basically very little planned import, just run off the batteries and charge from solar in the day.
Go and iGo show about 25-40p a day better profit from charging overnight, a bit of exporting and then re-charging, and then letting all the solar export the next day.
For me in the summer this wouldn't be a good strategy, I want to have the batteries empty at the start of the day so I can trickle feed them during the day to reduce clipping,
So at the moment Cosy or Agile is much of a muchness. Agile has the price plunges occasionally so slight upside.
Yes of course you are right, I could go onto agile or any other tariff, nothing technically stopping me. It’s just the practicalities of it for me with my plant set-up. (And the fact that it would likely cost me more).
I’m pretty sure having two ‘external’ automations running at the same time; predbat or something else and the balancer software controlling my inverters (by pausing and un-pausing one inverter at a time individually (and constantly)) they would fight each other and both would struggle to work properly. One bit of software could be sending a command to both inverters right after the other sends an opposing command to a single inverter and that wouldn’t be helpful !
I haven’t tried it for that reason. Also I don’t have direct control over the balancer software; I can’t just turn it on or off myself, I have to send an email to one particular GE employee to either turn in on or turn it off, which can take some time depending on their availability. And when it’s off I’m getting extreme cross charging. My plan is to wait for the hybrid EMS and then all my problems are hopefully solved. I do feel like I’m at the mercy of GE at them moment until I an able to get an EMS fitted. If the balancer software becomes unavailable for any reason I’m stuffed; my system doesn’t work properly! I guess if that happened then would be the time to force me to use predbat or something else. Am I right in thinking that predbat can manage cross charging or doesn’t it do that?
Perhaps we need to start a “cross charging management” thread? I feel like I’m hijacking this one.
[unknown] Go and iGo show about 25-40p a day better profit from charging overnight, a bit of exporting and then re-charging, and then letting all the solar export the next day.
For me in the summer this wouldn't be a good strategy, I want to have the batteries empty at the start of the day so I can trickle feed them during the day to reduce clipping,
Perhaps I'm fortunate in having panels slightly west of south, so solar doesn't reach clipping territory until late morning: plenty of time to dump some of the overnight charge to make room for excess solar. So I charge to 100% overnight, and discharge down to about 70% around 10am. I ask IOG to have car ready by 9.30 before solar starts to get interesting.
Have you tried just turning off eco to avoid clipping? It maximises AC generation, and sends only the excess into the battery, so you don't need to err on the side of charging more than absolutely necessary.
Pete UK I’m pretty sure having two ‘external’ automations running at the same time; predbat or something else and the balancer software controlling my inverters (by pausing and un-pausing one inverter at a time individually (and constantly)) they would fight each other and both would struggle to work properly.
….
Am I right in thinking that predbat can manage cross charging or doesn’t it do that?
Predbat likes to be in control of what mode your inverter/battery is in all the time, and if it finds its not as it expects it to be then it will change the settings to match what it has on the plan.
Having said that you can (and I have) run my own cross-charging automation alongside predbat, and all that happened is if predbat found the battery was paused when it didn’t expect it to be, it just changed it to unpaused.
Predbat does have a balancing mode within it, it runs every minute (by default) and stops the batteries cross charging and tries to balance the SoC on them. I used it for a bit but then turned it off as I was concerned about the large number of inverter commands being sent, and then all the stuff about inverter registers having limited write cycles came up so I felt vindicated in my choice.
I could turn the new in memory inverter register option on and that would avoid the side effects of the repeated on/off controls.
At the moment I manage everything through predbat and have an automation that sets the max inverter charge rates at different points of the day. Set to zero on inverter 2 overnight (to stop cross charging), set to 1400W on inverter 1 in the morning to trickle charge battery 1, then 1100W on inverter 2 at midday to trickle charge battery 2.
This works pretty well. Setting the inverter charge rate to zero overnight doesn’t perfectly stop the cross charge, but it’s just a very gentle 200W cross charge that happens. Setting battery pause mode to pause charge would be better but its currently a predbat feature request
Ah-ha. Thanks for that, much appreciated. So it sounds like the ‘inverter battery balancing’ bit inside predbat is effectively doing what the GE balancer software is doing but then there are also the other additional control benefits, like being able to set multiple charge/ discharge slots etc. (I am only able to use one of the 10 discharge slots at present).
At least that means I have a fall back option which is great news. My system has been working properly for the last 9 months after over a year of trying to get it rectified to operate normally since install. I have been deliberately trying to operate it with only GE software controlling things until I was convinced it was working properly, so there was no doubt about any third party interference with it or possible arguments about warranty.
I’m happy with the way it operates now and my tariff.
The one thing that I would like to make it fully autonomous is to have an automated way to discharge all the remaining stored battery energy to the grid in the evenings. At the moment I’m simply adjusting the start time manually so that they are empty at 23:30. In summer it’s easy I don’t need to adjust it. Rest of the year I have to tweak it every so often. Do you know if that is something that predbat can adjust dynamically on a daily basis? ie if battery is 100% full at 7pm then discharge to grid until 23:30. If battery is 90% full at 7:30pm, discharge to grid until 23:30….etc? Is that possible to set up rules like that in predbat?
I’d like to get an EMS fitted but….
This has got me curious as to if I should just swap over to Predbat now instead. Surely I wouldn’t even need an EMS then? Or would I? Maybe it does things a lot faster..? 🤷🏼♂️
I should probably read the predbat threads. But with over 2,000 posts it put me off till now. Here goes….
Pete UK The one thing that I would like to make it fully autonomous is to have an automated way to discharge all the remaining stored battery energy to the grid in the evenings. At the moment I’m simply adjusting the start time manually so that they are empty at 23:30. In summer it’s easy I don’t need to adjust it. Rest of the year I have to tweak it every so often. Do you know if that is something that predbat can adjust dynamically on a daily basis? ie if battery is 100% full at 7pm then discharge to grid until 23:30. If battery is 90% full at 7:30pm, discharge to grid until 23:30….etc? Is that possible to set up rules like that in predbat?
Predbat doesn’t have the capability to define rules like that as it runs a continual cost optimisation. Every 5 minutes predbat runs the execute the plan and every 10 minutes the plan is re-evaluated, working out what is the optimal instruction to the battery/inverter based on your SoC, load forecast, solar forecast, import and export rates.
So things like discharging the battery to empty so that it can be filled up again on the cheapest electricity is all done automatically.
I won’t promise that it is 100% perfect, it has glitches and occasional weird behaviour, but its continually being developed and tweaked and will almost all of the time come up with a better plan than you could manually do.
You do have the ability to override what it is planning, forcing it to export, hold. battery, etc if you want it to.
Yeah it looks good. I read the install instructions up to about page 27. I’m sure it’s ok to set up but looks pretty daunting at first glance 👀. Now I realise why there are 3,000+ posts about it on the other thread.
A job for when I have a lot of spare time I think.
Pete UK Yeah it looks good. I read the install instructions up to about page 27. I’m sure it’s ok to set up but looks pretty daunting at first glance 👀. Now I realise why there are 3,000+ posts about it on the other thread.
I have spent a lot of my time improving the documentation, and keep on adding tweaks and changes as other people find things that are not clear
The 3000+ posts is because people keep asking questions! TBH it’s more of a discussion than all a stream of issues. Probably not worth trying to read them. There are some other threads on setting up predbat which are more useful than the ‘second year live on predbat’ main thread
Cheers
I jumped in and got HA on a PI working in about half a day.
NB I am 65 and not from an IT background
I spent a few hours now and again making my own dashboards and still tinker
I added predbat in about 1 hour and had a couple of minor problems that Geoffrey fixed (by answering my pathetic questions on here). Mostly by not following the guidance.
Very stable and works very well
@geoffreycoan I have spent a lot of my time improving the documentation, and keep on adding tweaks and changes as other people find things that are not clear
Is that on behalf of Trefor?/ or to help him out? Or is Trefor an alias of yours…? Either way good job. It looks pretty detailed and clear to me. The issue I have is of time. I work abroad but my family are in the UK and I commute back and forth, so time is always at a premium. I rushed trying to install Home Assistant one day, on an old Mac-mini but it came back with a file missing error right near the end of the process and wouldn’t run which really pi$$ed me off. (a Mac OS file I couldn’t locate anywhere on the internet !), so I came to a grinding halt. Perhaps the hardware wasn’t suitable, I’m not sure. I came to the realisation that I needed to install it on something else (newer probably), which I don’t have a suitable ‘something else’ right now and was loathed to splash out on when I don’t really need to. It was just for a bit of fun at the time to see what HA was like. I didn’t have time to order or go and buy a something else and wouldn’t have been local to install anything on it even if I could have got my hands on one.
I didn’t even realise Predbat ran on HA TBH. I’d heard of it but thought it ran on its own.
It’s something I’ll probably get around to eventually when I can spare a day. It does look good though.
Pete UK Is that on behalf of Trefor?/ or to help him out? Or is Trefor an alias of yours…?
No I am not Trefor Southwell. Never met him. It’s just my community giveback for what is an excellent piece of software. In lieu of payment I try to help out on the documentation and github issues
I am with Pete UK on this. Love tinker but time I don't want to waste or spend that I don't need to.
Settled for MyEnergyOptomiser and well pleased. While April has been an exceptional month for solar generation and solar home heating, I think my greatest saving has been removing gas and switching to the October Cosy tariff. The electric bill was a shade over £50. Without solar or the Cosy tariff it could have been near £100. With solar generation and export, I am very pleased with a bill of under £10.
I think bottom line, 'off the shelf' works but it can all be improved through fine tuning usage and tariff.
PS, trawling through the Daikin App I see my HW usage is constant at around 50kW/month after tweaking with a lower temperature and fewer heating times. This is 50kW less than in January.