Although using 21 kWh a day, that's going to be a large & expensive battery!
Although using 21 kWh a day, that’s going to be a large & expensive battery!
Unless he uses 21kWh at night it doesn't have to be that large. Its not good economics to size a battery to cover you in December as it will take an age to get payback. Most of the year solar will cover 20-100% of your requirements so size the battery accordingly.
Although using 21 kWh a day, that’s going to be a large & expensive battery!
Logical thinking would be to think of a battery as a capacitor.
Remove the export since rates are derisory (without being able to control when it's exported)
Going "off grid " is expensive ....how ever removing a large chunk of your import is reasonably cheap by comparison
We consumed 7783kWh last year, = 21kWh per day. Expecting this to go up next year with car charging.
If it helps with your working out, we produced 4000kwH in Glasgow last year (feb-feb). From all accounts that was a good year. We were quoted to expect approx 2500-3000kwh based on location/aspect. That’s a south facing roof with 4.6kw panels tied in to the standard 3.65kw inverter. No battery.
Be advised though, 70% of the production occurred feb-august. August-Feb sporadic at best in Glasgow. Our biggest saving comes from the iboost to heat the water.
I finished installing the second battery today along with all of the associated wiring and ducting - just in time too. Even given the power off time whilst I wired it up, it was a 17kWh day! Saw a new peak power from the array of 4.89kW, but only briefly as it’s intermittently cloudy.
There’s now ~19kWh of storage on the side of the house, which should do us even on very busy days.
I wish there was more information from
The BMS about how it’s doing its job between the packs as they’re quite different in size to one another, but I can’t find anything through the inverter. I’ll try to ask LG.
New peak for us ...from a 4.14kWh array plugged into a 3.6 inverter.
Never saw that in the last 18 months. Peaked at 3.8kWh last April with the last 3.6 inverter. Summer sun never gets close to that with the excess heat.
Remove the export since rates are derisory (without being able to control when it’s exported)
I buy at circa 18p a kW on Eco7 then if I do export any I get circa 15p per kW. I dont buy any at the expensive rate since early Feb so the export works ok for us.
Trailrat what app is that? 😁
Solis numberjumbler app
Remove the export since rates are derisory (without being able to control when it’s exported)
We've just signed up to Octopus' dynamic export rate, although not yet seen the prices they offer.
Not sure if it's the same as their "Agile" tariff, where the unit price varies every 30 mins.
If doing a smart plug immersion solution to excess generation, can I stick a dimmer switch rather than an on off after the fuse spur
to scale down consumption? Problem is the inverter can only push 5kw so if i boil the kettle then I’m drawing power from the grid.
Will that shorten its life?
I buy at circa 18p a kW on Eco7 then if I do export any I get circa 15p per kW. I dont buy any at the expensive rate since early Feb so the export works ok for us.
hence the my brackets in your original part quote - what you are doing would not be possible without the ability to control when the export happens ( IE batteries)
f doing a smart plug immersion solution to excess generation, can I stick a dimmer switch rather than an on off after the fuse spur
to scale down consumption?
that sounds like a really shonky and quite probably dangerous way to solve something where an off the shelf qualified product exists already to perform that function.
worth noting that few smart plugs are rated to an immersions draw on continuous current. most will do it peak but not continuous.
Problem is the inverter can only push 5kw so if i boil the kettle then I’m drawing power from the grid.
The immersion shunt unit should sense that you're pulling current from the grid and back off the current to the immersion whilst the kettle is boiling.....
Plus, how long do you boil a kettle for? 1 minute tops?
Yes having done a quick google, lighting doesn’t run at 13 amp so a high current rheostat is needed and it needs a heat sink too.
If there’s a dimmer will the smart plug need to do 13a - theoretical question. I’ve discounted as not a very practical idea.
Footflaps- I don’t have an I boost or similar so immersion just runs at full tilt when on
Footflaps- I don’t have an I boost or similar so immersion just runs at full tilt when on
doing that manually will get boring very fast
Yes having done a quick google, lighting doesn’t run at 13 amp so a high current rheostat is needed and it needs a heat sink too.
Normally dimmers just chop the 230v using triacs so the on period is less than 100% (or at least the ones I used to build). I assume someone would make a 13A version...
A rheostat sounds like a very old school solution.
might it be easier to run two small immersion heaters off two plug switches?
Footflaps- I don’t have an I boost or similar so immersion just runs at full tilt when on
You could automate it - I have a system [that uses a Pi, IFTTT and a Warmup wireless thermostat] to switch the electric underfloor heating on and off when there's enough generation which works pretty well.
But that's 'only 800w so if there's an overlap of a few minutes when the generation has dropped but the floor is still on then it's not the end of the world, but 3kW is another matter. And the times when your panels are producing more than 3kW + your house background usage are going to be fairly limited.
You're much better off stumping up for a diverter - it's the best solution for water heating.
might it be easier to run two small immersion heaters off two plug switches
That assumes two immersions in the tank - and still a PITA.
You’re much better off stumping up for a diverter – it’s the best system for water heating.
Or not worrying about drawing off the grid for 30 secs when you boil the kettle....
Although I realise it becomes quite obsessive. I worry about sequencing kettle, microwave and grill when cooking, so as to never exceed our 3.8 kW inverter limit. Totally pointless in the grand scheme of things, but I do 'get it'!
We’ve just signed up to Octopus’ dynamic export rate, although not yet seen the prices they offer.
Not sure if it’s the same as their “Agile” tariff, where the unit price varies every 30 mins.
Been on the agile since install, just moved onto the 15p tariff as we were consistently below this threshold very rarely above 15p.
what you are doing would not be possible without the ability to control when the export happens
Not really. My batteries dont allow me to choose. Excess solar goes to my batteries, then my solar diverter then back to the grid. It happens sporadically during the day when none of the others have any demand.
Anyway I am looking to extend the PV I have from 5.6kW (5kW inverter) to around 8kW to provide for the increased draw that my future EV will demand. If I didnt export to the grid (at around 15p per kW) then each kW would provide around 3 miles (dependent on several factors of course) of range (of course I give up the export benefit so its not free) but in Feb alone I have estimate around 180 miles so far. Thats roughly half our car monthly mileage.
If I add 2.8kW (assuming I can) then should I add another inverter or feed into the current one??? Tempted to add another as even in Feb I have seen bursts of >5kW so I would be giving quite a lot of free energy away...
Been on the agile since install, just moved onto the 15p tariff as we were consistently below this threshold very rarely above 15p.
Do they use the same value for import and export on Agile?
Or does the export have a lower dynamic value?
True!
As you said, doing it manually is going to get old very quickly - you could switch it on then go out and it cloud over leaving the immersion on, or just forget to switch it off!
If I add 2.8kW (assuming I can) then should I add another inverter or feed into the current one???
I have wondered how this works, I assume they talk to each other (I think the Huawei ones do anyway). Otherwise the whole backing off thing might be a bit random as each thinks it is the only inverter in the system. Or maybe they co-exist fine. Pretty sure with Huawei all the inverters link via Ethernet so act as one.
That assumes two immersions in the tank – and still a PITA.
you can (I think) get dual element immersion heaters for exactly this purpose - the original purpose was one of them run off the economy 7 timer and one for boosting. No idea if they'd be too powerful when both run together
its worth noting that immersion heaters should be run off dual pole switches, which I doubt any remote control plug hack would achieve.
I assume they talk to each other
I'm pretty sure the Foxess ones work alongside each other and have seen screenshots of the software supporting that. Quite pleased with the vendor so far (battery and inverter) so no need to change I suppose but as the roof is low it is borderline DIY.... Obvs with an expert to make the final connections.
export is way lower than import for obvious reasons orherwise many would just load shift back to grid when prices above import. i was on the dynamic agile export averaged 10-13p, so a flat 15p is better for me. Im still on E7 for import, want to move onto tracker but there is now a 6 month wait as they are only doing 50 applications a day. Flat rate will have to do meantime
http://mysmartenergy.uk/ gives you the details
If I add 2.8kW (assuming I can) then should I add another inverter or feed into the current one???
This is what I want to do and I'm going to add another inverter for a couple of reasons:
1) Existing array is on two strings and the inverter accepts two strings, so there's no room for a third string [extra panels would be ground mounted]
2) My existing FIT does not allow any alterations to the equipment and I'm not going to risk the [substantial] income that provides!
Two questions..... will your existing inverter take the potential generation from a combined 8kW array and will your DNO allow an increased generation (or are you not going to tell them?
Not really. My batteries dont allow me to choose.
I think your misunderstanding.
With batteries you have a choice.
Without you have no choice
@sharkbait Good questions I will have to check the spec in detail of the inverter. My setup also already has 2 strings. I am waiting for a call from my installer and happy to be open with them and see what they suggest.
Solis numberjumbler app
Ah - fellow tea leaf readers.
I think your misunderstanding.
How so?
I think your misunderstanding.
How so?
I have absolutely no idea.
If you are upping generation (and the new inverter is linked to the grid) You will still need to advise your dno with a gn99 or whatever the form is.. might be worth checking they view this as “not a change”
Two questions….. will your existing inverter take the potential generation from a combined 8kW array and will your DNO allow an increased generation (or are you not going to tell them?
I’m pretty sure that risking the payments on the FIT scheme is the least of your concerns, as OFGEM monitor individual trends and can not only demand a full repayment of anything paid to you under the scheme, but then cheerfully pass the entire case over to the police.
A system diagram is placed on record when the system is installed, so it’ll be immediately obvious if anyone visits to read the meter (or because your generation trend has doubled) if it’s been modified.
It’s honestly not worth fiddling. Any new system needs to be completely independent from the existing install. That’s not to say that you can’t do it, but you need to be very careful about how it’s done.
It’s honestly not worth fiddling.
Agree. Thats why I said this
I am waiting for a call from my installer and happy to be open with them and see what they suggest.
It’s honestly not worth fiddling. Any new system needs to be completely independent from the existing install.
That's certainly my feeling.
I’m pretty sure that risking the payments on the FIT scheme is the least of your concerns, as OFGEM monitor individual trends and can not only demand a full repayment of anything paid to you under the scheme, but then cheerfully pass the entire case over to the police.
A system diagram is placed on record when the system is installed, so it’ll be immediately obvious if anyone visits to read the meter (or because your generation trend has doubled) if it’s been modified.
It’s honestly not worth fiddling. Any new system needs to be completely independent from the existing install. That’s not to say that you can’t do it, but you need to be very careful about how it’s done.
Fairly sure that surfer doesnt get FIT payments - in which case im not sure why anyone would be handing anything to the police.
as for the system diagram - you over estimate the system -- ive seen whats on record for my system at DNO level and it amounts to a piece of paper that says ive installed solar and i wont export more than 3.6.
The MCS which is not a legal requirement has a kit list and a schematic but no one will be chasing based on that
I'd be genuinely amazing if anyone is checking up on installed systems and also amazed if the records were correct for most installed systems....
It's probably all stored on a access database somewhere.
My G99 cert was far more comprehensive and the paperwork from the DNO arrived back from them with all of my system diagrams, etc embedded into the sign off paperwork.
Another shout out for the accuracy of the PGIS Database. Its not totally clear how many Kw my system would generate in February from the graphic but I read that as being 280kW (28 day Feb) As it stands (its cloudy here so may get another kW or so today) I have reached 279.08kW which seems an incredibly accurate estimate...
Its not totally clear how many Kw my system would generate in February from the graphic
If you hover over the graph in the original web page it tells you the actual value for each bar.
