Free Energy

[mikgle]

I was averaging at least 10 kW load for the full hour, at times pulling 15 kW.. 2 x storage batts plus my ev plus hot water tank.
At this time of day my grid usage is always zero so no cost to me.
Now to export most of it back to Octopus @ 15p/unit..
Soon I might be able to retire! Bring on the next one..

I didn't anticipate the Zappi refusing to engage Fast mode from its own controls, instead needing something done on the app. Maybe John's suggestion would have been better, I can try that next time. I got 5.79 kwh into the car anyway, a little less than I anticipated but worth having. The Eddi got 2.8 kwh and even though I took that shower in the middle of the free period (power shower also consumes electricity) the water is still pretty damn hot now.

So on top of the 8.6 kwh the MyEnergi appliances got, there was the power shower and the use of the vacuum cleaner. Worth it for the learning. I obviously don't know nearly enough about how the Zappi functions.

Car now at 74%, so I just need to get a schedule from Octopus to add 30% tonight.

While I was clearing up outside my neighbour's father (not the neighbours with the same solar installation as I have, the people on the other side) drove up in - a dual motor Tesla Model Y. He was talking about getting a Tesla the last time I spoke to him, and apparently he took the plunge in June. He says it takes a bit of getting used to but he's getting to love it. He said he'd heard about the free hour but since he wasn't at home he couldn't think what to do about it. So he must be on Octopus too.

yes you need to Bump charge it off the Octopus app.. usually takes a minute or two.

 

[Rolfe]

I couldn't find the Bump charge command at the time, though it's clearly there now! It did work just doing it through the Zappi, what I hadn't anticipated was that it would insist on me changing the settings on my phone, and I still don't quite know what I did to get it to play nice.

This all happened during the best solar generation period of the day, so given that I wasn't exporting that at the time, that has to be subtracted from my "winnings".

I haven't even tried exporting back to Octopus from my home battery. Give me a chance, I've only had my export tariff for nine days! I'm not sure how it works. As far as I know I can only export a maximum of 5 kw, so for the time when the solar is showing a lot of excess I can't export from the battery, can I? If I'd wanted to export to get the battery low to accept charge during the free period, well, there was quite a bit of export going on anyway in the hour before the free hour, so presumably I couldn't have done it then. But if I'd done it earlier, I'm not sure how to stop the thing just charging off the solar before the free period. Need to think about this.

Here's what my GivEnergy power graph looks like now. The stuff at the beginning is the fallout from my having run the fan heater from about 8.30 to 1am because it was a chilly evening and I was watching a rather long opera stream. So the battery was down to 43% at 11.30 when it started to recharge. It got back up to 100% at 1.30 am, so two hours. There was a lot of import between midnight and 1am, because the fan heater was still running in parallel with the battery charging.

The house load minimised when I went to bed, and at 5.30 the house stopped using the grid (no Eddi 4.30 to 5.30 because I forgot to turn it on before I went to bed) and called on the battery, which went down to 97% thereafter. By just after seven there was enough solar to let it charge again, and it was full by 7.35. Everything was quiet, just the normal house load and export happening, until it all went mad during the free hour, then back to normal again with that kettle boiling from the solar at quarter to three.

So my question is, what could I have done so that the house battery was also charging during that time? When could I have either stopped it charging or exported charge, that would have seen it low enough to charge at 1 pm?

And on a wider note, I note that my battery is pretty much always close to full now. In the morning it only uses about 3-4% to run the house between the off-peak period ending and the solar taking over, and in the evening it often only uses about 10% between the solar fading and the off-peak kicking in again. Depending on what I use, of course. If it's a warm evening that fan heater isn't going to be on.

So is there something I could be doing to exploit this? To export what's in the battery for 15p, but not then promptly cancel that out by the thing charging itself on solar I would have got 15p for anyway? How are other people managing this?

 

[mikgle]

I couldn't find the Bump charge command at the time, though it's clearly there now! It did work just doing it through the Zappi, what I hadn't anticipated was that it would insist on me changing the settings on my phone, and I still don't quite know what I did to get it to play nice.

This all happened during the best solar generation period of the day, so given that I wasn't exporting that at the time, that has to be subtracted from my "winnings".

I haven't even tried exporting back to Octopus from my home battery. Give me a chance, I've only had my export tariff for nine days! I'm not sure how it works. As far as I know I can only export a maximum of 5 kw, so for the time when the solar is showing a lot of excess I can't export from the battery, can I? If I'd wanted to export to get the battery low to accept charge during the free period, well, there was quite a bit of export going on anyway in the hour before the free hour, so presumably I couldn't have done it then. But if I'd done it earlier, I'm not sure how to stop the thing just charging off the solar before the free period. Need to think about this.

Here's what my GivEnergy power graph looks like now. The stuff at the beginning is the fallout from my having run the fan heater from about 8.30 to 1am because it was a chilly evening and I was watching a rather long opera stream. So the battery was down to 43% at 11.30 when it started to recharge. It got back up to 100% at 1.30 am, so two hours. There was a lot of import between midnight and 1am, because the fan heater was still running in parallel with the battery charging.

The house load minimised when I went to bed, and at 5.30 the house stopped using the grid (no Eddi 4.30 to 5.30 because I forgot to turn it on before I went to bed) and called on the battery, which went down to 97% thereafter. By just after seven there was enough solar to let it charge again, and it was full by 7.35. Everything was quiet, just the normal house load and export happening, until it all went mad during the free hour, then back to normal again with that kettle boiling from the solar at quarter to three.

View attachment 29202


So my question is, what could I have done so that the house battery was also charging during that time? When could I have either stopped it charging or exported charge, that would have seen it low enough to charge at 1 pm?

And on a wider note, I note that my battery is pretty much always close to full now. In the morning it only uses about 3-4% to run the house between the off-peak period ending and the solar taking over, and in the evening it often only uses about 10% between the solar fading and the off-peak kicking in again. Depending on what I use, of course. If it's a warm evening that fan heater isn't going to be on.

So is there something I could be doing to exploit this? To export what's in the battery for 15p, but not then promptly cancel that out by the thing charging itself on solar I would have got 15p for anyway? How are other people managing this?

I also have the Givenergy app, I use the graph mode etc which you have shown, on my computer and you can adjust the settings on the options shown under inverter settings but the easiest way is on my smartphone I have a more succinct view with fewer options, under settings you can switch between eco mode and export mode as required. and back again obviously. You can export the battery in addition to the solar export, just as you can force charge the battery as well as solar charge. Note the export option disables the normal eco setting and vice-versa. You may have to watch a givenergy tutorial or contact them if you need to, explaining what youre trying to do. It does take a bit of practice so be patient, its even worse when you have two batteries of different makes which dont talk to each other! On my giv battery there is a on/off button on the side which is sometimes the easiest way to stop it exporting..

 

[Rolfe]

Yes, I do all the changing of settings on my phone. I did go through all the settings I could see to find out what was possible, but my main problem at the moment is that I don't actually know what I want to do. I've just picked up the idea that I could be improving the efficiency of what I do by doing a bit of buying at 7p and selling at 15p, except I haven't got my head round either when or how.

I didn't know it was possible to export more than 5 kw if my G99 just says 5 kw. Does it not count export from the battery in that, or something? Or am I misunderstanding? I was just thinking, I used 50% of the battery yesterday evening just before the off-peak price kicked in, but if I hadn't, could/should I have exported that (and more)?

Well, serious export seems to be over for the day. I'm going to try to sum up, on the assumption that not a lot will happen between now and midnight (unless it gets colder and I turn on that heater again).

Total import was 13 kwh, but that includes a chunk between midnight and 5.30 am. The total import during the free hour was only 5.92 kwh, to a large extent because the solar was going pretty well at that time, and the 3.22 kwh generated in that hour went to the house instead of export. (That makes total power usage during the hour 9.14 kwh.)

Therefore, right at the start I'm down 48.3p in lost export fees.
On the other hand I got for free (if they pay me) power that would have cost 41.44p at the off-peak price.

So it seems I actually lost nearly 7p over the whole exercise. Unless someone can tell me different. (Of course I have gained a lot in increased understanding of the system.)

If the whole thing had happened at a time when there was no solar export to lose (or indeed if it were possible both to export the solar while importing the free electricity, which doesn't seem compatible with the laws of physics to me), I'd have been a whopping 64p in profit. The solar was a lot poorer between 11 am and noon (only 1.37 kwh), so if that had been the free hour I'd only have lost 20.55p in export and so been 20.9p in profit rather than losing 6.9p. It just so happened that the sun came out at noon.

Total export for the day was 15.9 kwh to set against that import total of 13 kwh, so the whole day should be washing its face even with the standing charge. Of course if they don't pay me and I end up getting charged for the 5.92 kwh at peak price, I will be down - £1.37. Which will be chalked up to experience.

I think the message I have from this is that unless the free hour happens during big black thunderclouds when solar is minimal, it's not going to be worth the hassle and might well generate a loss. Even if it does happen when solar is minimal, we're talking buttons. Even if I'd been able to charge my home battery as well during the hour (God alone knows how) that would only have been about another 3.5 kwh claimed (due to the maximum charge speed of the battery) so another 24.5p on the credit side.

I think the most I could have managed during that hour, even allowing for getting the Zappi to start on time and charging the home battery as well, was 15 kwh. With a very fair wind. That's the equivalent of just £1 at off-peak prices. Even if by some miracle that happened at a time when I was losing no solar export at all, it's not worth the bother. If it happened at a time when solar export was maximum, I'd only be 30p in profit.

If anyone can spot a flaw in my calculations or logic, feel free.

 

[Bam Bam]

Well, serious export seems to be over for the day. I'm going to try to sum up, on the assumption that not a lot will happen between now and midnight (unless it gets colder and I turn on that heater again).

Total import was 13 kwh, but that includes a chunk between midnight and 5.30 am. The total import during the free hour was only 5.92 kwh, to a large extent because the solar was going pretty well at that time, and the 3.22 kwh generated in that hour went to the house instead of export. (That makes total power usage during the hour 9.14 kwh.)

Therefore, right at the start I'm down 48.3p in lost export fees.
On the other hand I got for free (if they pay me) power that would have cost 41.44p at the off-peak price.

If anyone can spot a flaw in my calculations or logic, feel free.

Not sure if I missed something but looking at the bigger picture didn't you shift some of your consumption from when it would be more expensive (albeit in your case that is cheap overnight) to when it was free.

Or do you think you used power you wouldn't have ever used otherwise?

 

[Rolfe]

The issue was that although I did that, I also used solar that would otherwise have been exported at 15p to power all the things I was doing. As it happened, the amount of export income lost was a few pence more than the gain from getting some power free that would otherwise have been 7p.

I didn't use any power I wasn't going to use anyway. The car is on to charge tonight, with 5.8 kwh more in the battery than it would have had without this exercise. Because I forgot to switch the Eddi on last night my hot water wasn't very hot this morning, so the opportunity to run the Eddi and have a hot shower during the free period was fine. But I could have done that from the house battery anyway, albeit again losing a bit of solar in the process. I did intent to vacuum the car boot this afternoon, so I did it during the free period.

But basically, although I would have foregone a bit of solar doing these things without any free period, the bulk of the issue was that the car was getting solar along with the "free" electricity, and that would not have happened otherwise, because it would have been charged overnight.

I could perhaps re-jig it and say, well the hot water and the hoovering would have eaten into the solar if I'd not had the free offer, so perhaps I'm a few pence in credit after all. But if it hadn't been for my forgetfulness last night the water would have been heated without compromising solar export, and as I said, the car would have been charged without using any solar either.

All that running around, and I don't see how to make it more than pennies in profit at best. It's not worth running anything that you would otherwise be able to do at night (car, water heating, washing machine, dishwasher, tumble dryer) if there's even a moderate amount of sunshine, because you're losing 15p export as the price of saving 7p off-peak import.

Doing things you can only do in the daytime, like the vacuuming and even the power shower (I'm not shifting my shower times to off-peak, thank you) aren't going to add up to a lot of savings in an hour.

I may have got this entirely wrong, but that's how the sums seem to me. Not worth it unless there's going to be an hour of black thunderclouds or an eclipse of the sun, and even then, is it worth it for about £1?

I'm now more interested in figuring out how to profit by discharging my un-needed battery to the grid before filling it again. I could do it now. The damn thing has only just dipped to 98%, and there are less than three hours to go until it can be filled at 7p. There's power to spare. I just haven't figured out the logistics. That could actually net me up to £1.35, and it's something I could do every evening, even - perhaps especially - when I'm away from home. It could perhaps be automated, but I'm not sure how.

 

[Rolfe]

OK, this is interesting. But I'm going to take it over to the thread about my own system, because we've left the topic of Octopus's freebie hour in the rear-view mirror.

 

[mg4mc]

My results are in for 15th August - I used an extra 6.6 kWh..

You used 2626% more than usual: 158p worth of Free Electricity

 

[Rolfe]

Well done! Did you lose much solar over the hour? Or doesn't it work like that with your setup?

 

[mg4mc]

No solar for me, that was just plugging the car in and doing a wash cycle

They said Octopus customers used up 531 MWh of surplus green energy.

 

[Rolfe]

Excellent. It seems it works well for some people. It might work for me if there was no sunshine for the hour in question I suppose.

 

[DaevM]

Hilariously I received an email from them saying use Octopus OCPP to charge your car by Monday or you're back to Octopus Go rates about 2 hours before I got the email from 'Pete' telling me how well I'd done in using 4.88 kWh of extra electricity on Friday, saving me £1.14 (whoop!!) .
What with solar doing its thing, free electricity being given away and my vehicle usage dropping though the floor I'm finding it difficult to fit an Intelligent Go schedule in. Just been for an essential wine run to create space in the battery for a 10% charge. Hopefully that'll keep 'em off me back for another month.
'twas never so complicated ( or cheap) with fossil fuels ??

 

[mikgle]

I did 8.92 kWh more, so saving £2.08
What I also discovered though on these greenest days is that if you plug in on Intelligent Go there is also a much bigger cheap rate window on the day, like from 3pm to 4pm and from 9.30pm onwards too.. if you have anything left to use it for that is!

 

[GaryMG4]

Very late notification for the first session meant I didn't have time to set much up, plus with it being sunny I had a fair bit of excess so I saved a total of 35p! Be interesting to see how I did on the subsequent sessions.

 

[JimD]

94p

 

[DaevM]

94p

Milky Bars are on you ??

 

[Grandadgeorgec]

94p

Car charge, washing machine and odd batteries charged (vacuum cleaner etc)
You used 180p worth of Free Electricity ️?

 

[Alb]

8.63kWh for me although most of that was due to charging of course so the true saving is mostly at 8.5p/kWh.

 

[mikgle]

Tomorrow's the 18th. Do you mean tomorrow or Monday?

Thanks for that. I hadn't signed up because of the full car at the last free slot, so didn't get any notification. I've signed up now, so hopefully I will get the notification.

The car is sitting at around 60% now waiting to be charged for the start of a road trip on Tuesday morning. I can swipe what I can get either Sunday or Monday. I just have to remember to set the house battery to charge at the same time (although it will be at 100%) to avoid the Zappi draining it while it charges, and get everything from the mains.

You could just switch the battery off when its full perhaps? On mine there is a simple push button to do this, press and hold for a few seconds to switch off, press again to start. The inverter stays on..