Pocster Posted January 13, 2022 Share Posted January 13, 2022 https://www.solaredge.com/uk/ Very interesting and confusing conversation with guy who came out to look at the possibility of another PW2 If DNO deny then that's it. As my output/drain ( i.e. charging everything up at cheap rate ) upsets Mr. Grid With SolarEdge ( as far as I understand it ) the battery storage is before the exporter. So that's currently limited to 3.6Kw. With2 PW2 at 5KW each they could argue 'drain' can exceed what they will permit ( they could limit export to prevent issues the other way ). As SE is before the exporter/inverter it doesn't constitute a problem i.e. the inverter is limited to 3.6KW and I could in theory have 10 SE batteries for storage ; but I can never use more than 3.6KW Assuming I've got that half right, has anyone looked into this?. I believe SE is new in the UK. Installer said they are currently limited to 1 SE install a month, until supply picks up. Not too much of an issue as they only have 1 install booked in! Link to comment Share on other sites More sharing options...
Pocster Posted January 13, 2022 Author Share Posted January 13, 2022 (edited) Having said all that I'm now confused how the SE charges (ignoring PV )...... Must be only PV.... Edited January 13, 2022 by pocster Link to comment Share on other sites More sharing options...
Pocster Posted January 13, 2022 Author Share Posted January 13, 2022 I decide to confuse myself more and use this... https://www.rapidtables.com/calc/electric/kW_to_Amp_Calculator.html I have an 80Amp fuse. A PW2 can draw at 5Kw. so 10Kw for 2. EV charger can draw at 7.5kw So sticking 17.5kw in = gives just under 73Amps I wonder how much 'room' they allow for normal house hold use on top of that? i.e. how near are you allowed to get to 80A.... Link to comment Share on other sites More sharing options...
Pocster Posted January 13, 2022 Author Share Posted January 13, 2022 If you have an 80A fuse (modern wiring) is that sufficient to upgrade to 100A? - or does that require main inlet cable replaced? Link to comment Share on other sites More sharing options...
Carrerahill Posted January 13, 2022 Share Posted January 13, 2022 7 minutes ago, pocster said: If you have an 80A fuse (modern wiring) is that sufficient to upgrade to 100A? - or does that require main inlet cable replaced? It depends to be honest, but unless you are planning on sitting at high current for a long time you would probably be fine on an 80A even for 100A unless it was for days straight. You really only have a big issue after about 120A where even then you would get about 1000seconds before it goes. However, your main isolator would now be overloaded unless you happen to have a 125A - doubt it. So you need to be careful here, but the cut out and the cable are probably not going to be an issue for you, more your own electrical equipment. When they joint an LV lateral cable which runs from your cable head to the LV street network there is no protection at the joint, the local upstream protection will be at a substation outlet and could be 1250A or maybe 3000A, sometimes more in cities, so the cable might be jointed in the street and be say a 10m run of cable, so the BS88 fuse needs to sort of work in reverse to protect the lateral cable. Often in new builds I have spotted 80A BS88 but I suspect you could slip a 100A BS88 in no sweat, i.e. if the cable is 25mm, which will be concentric. It would be possible to draw about 150A for a limited time on the cable without any damage, it is all about current x time. Here is a quick protection study I did for an 80 (red) and a 100 (green) fuse and a 1250 (blue) upstream fuse - note that it would take over 1 hour at 100A really for both the 80 or 100 to trip - you will note that the 1250 would even allow 5000A to pass for about 100s. 1 Link to comment Share on other sites More sharing options...
Carrerahill Posted January 13, 2022 Share Posted January 13, 2022 (edited) 1 hour ago, pocster said: I decide to confuse myself more and use this... https://www.rapidtables.com/calc/electric/kW_to_Amp_Calculator.html I have an 80Amp fuse. A PW2 can draw at 5Kw. so 10Kw for 2. EV charger can draw at 7.5kw So sticking 17.5kw in = gives just under 73Amps I wonder how much 'room' they allow for normal house hold use on top of that? i.e. how near are you allowed to get to 80A.... Probably more like 77A as PF would not be 1. You are now beginning to see the issues that the network operators are having to contend with. There is a document called ESDD-02-012 which gives the SPEN ratings for supplies for various house types, for clarity this is not fuse size but supply rating, in other words how they work out how many supplies they can give from a given substation. A 5 bed property with gas heating is given as 2kVA - that is about 8.7A at 230V - that is what they are allowing. They used to give you 18kVA - but they realised that at that figure they didn't have enough capacity on the grid, so they just decided to drop the rating. This 2kVA is known as the After Diversity Max Demand. ADMD. They apply this city wide and sort of hope everyone is not charging EV's in the evening when they get home or making dinner... no wait... they are... why is no one talking about this? Oh, I remember because they are banning gas and petrol and diesel and the facts don't suit their narrative. Electric future... maybe in 2060 but not the next decade. They will start to make U-turns soon. Gas prices are only high because they want to use gas for electric generation as coal is too dirty, that is even before we all ditch petrol and diesel and gas domestically. Edited January 13, 2022 by Carrerahill 1 Link to comment Share on other sites More sharing options...
Pocster Posted January 13, 2022 Author Share Posted January 13, 2022 1 hour ago, Carrerahill said: They apply this city wide and sort of hope everyone is not charging EV's in the evening when they get home or making dinner... no wait... they are... why is no one talking about this? Oh, I remember because they are banning gas and petrol and diesel and the facts don't suit their narrative. Electric future... maybe in 2060 but not the next decade. This is exactly what I was thinking!. If DNO has to 'restrict' then that limits amount of PV, batteries, EV etc. etc. a particular household/area can have. I guess upgrading infrastructure ( sub stations etc. ) will be no small ( cheap! ) task. Appreciate your other detailed response aswell ? I'm being greedy and want maximum supply ( not too worried about export ). I suspect that I'll be refused from the DNO as charging 2 PW, an EV and running other electrical stuff for 4 hours will be too much for 80A. If they let me upgrade to 100A ( as a condition of approval ) then I'd be up for it. Should find out in a week or so.... Link to comment Share on other sites More sharing options...
Carrerahill Posted January 13, 2022 Share Posted January 13, 2022 (edited) 13 minutes ago, pocster said: This is exactly what I was thinking!. If DNO has to 'restrict' then that limits amount of PV, batteries, EV etc. etc. a particular household/area can have. I guess upgrading infrastructure ( sub stations etc. ) will be no small ( cheap! ) task. Appreciate your other detailed response aswell ? I'm being greedy and want maximum supply ( not too worried about export ). I suspect that I'll be refused from the DNO as charging 2 PW, an EV and running other electrical stuff for 4 hours will be too much for 80A. If they let me upgrade to 100A ( as a condition of approval ) then I'd be up for it. Should find out in a week or so.... Go for maximum generation capacity you can afford and feel you can benefit from - remember that a PV array could be done in increments. I use a little micro inverter so I can add 1 panel at a time and if I want to make 1 array different products from another or high peak output capacity panels I can simply add those by sizing the inverter accordingly. First solar panel is going on the shed, the next 5-7 on the garage and the following 5-7 on the house. Work starts ASAP really. I set it all up temporarily and generated 1.25A with one panel at 15:00 with some low winter sun! I will take that! You can stop export, if I am honest I would rather use my own generated power rather than export it given the rate I was offered, 3p v's the 23p I pay, so I am not planning on exporting, you can get inverters and controllers that know what to do with excess, 1 chap I know dumps it into huge hot water buffer tanks. If on a very sunny day when his buffer tanks were up to temp and all the laundry and what not was done then his system just does nothing. Might seem wasteful but he has never had this eventuality yet. He clearly sized his generation capacity to suit his use. Battery storage is the next option, not something I am currently even thinking of but would think about it when electric is 40p a unit and I am wasting it during the day. If you could afford to store all your solar, then go for that option. But size your system wisely and don't let a PV company size it because they are of course going to say you need more than you really need. But remember, you can always add! Edited January 13, 2022 by Carrerahill Link to comment Share on other sites More sharing options...
Pocster Posted January 13, 2022 Author Share Posted January 13, 2022 (edited) 16 minutes ago, Carrerahill said: Go for maximum generation capacity you can afford and feel you can benefit from - remember that a PV array could be done in increments. I use a little micro inverter so I can add 1 panel at a time and if I want to make 1 array different products from another or high peak output capacity panels I can simply add those by sizing the inverter accordingly. First solar panel is going on the shed, the next 5-7 on the garage and the following 5-7 on the house. Work starts ASAP really. I set it all up temporarily and generated 1.25A with one panel at 15:00 with some low winter sun! I will take that! Now this is where I'm confused. My inverter can only ever export 3.6kw. So I could add a zillion PV panels but in reality I need something like SolarEdge to store the electricity . I also didn't realise that I have 2 sets of panels on either side of my ridge and apparently a shadow will 'knock out' the entire ridge. Whilst with solar Edges 'optimiser' one panel in shade will not effect power generation from the others. Not sure of how much the actual benefit would be .... 16 minutes ago, Carrerahill said: You can stop export, if I am honest I would rather use my own generated power rather than export it given the rate I was offered, 3p v's the 23p I pay, so I am not planning on exporting, you can get inverters and controllers that know what to do with excess, 1 chap I know dumps it into huge hot water buffer tanks. If on a very sunny day when his buffer tanks were up to temp and all the laundry and what not was done then his system just does nothing. Might seem wasteful but he has never had this eventuality yet. He clearly sized his generation capacity to suit his use. Agreed. I rather export zero at 3p a KW and keep as much as possible for myself rather than buy it back at 5p off peak or 25p peak. The engineer claimed it is possible to 'stop' export via a device that is controlled presumably by the DNO to stop over generation. To his knowledge he hasn't seen one installed on a domestic property yet. Just a few hundred quid apparently... 16 minutes ago, Carrerahill said: Battery storage is the next option, not something I am currently even thinking off but would think about it when electric is 40p a unit and I am wasting it during the day. If you could afford to store all your solar, then go for that option. But size your system wisely and don't let a PV company size it because they are of course going to say you need more than you really need. But remember, you can always add! I understand your wait tactic. Problem is ultimately that day will come and by then ( as even now ) demand for batteries outstrips supply. Also I note Tesla for example have increased the price of their batteries - extra money for old rope. TBH he didn't really push the extra PV option it was just a consideration that even in his own wording was 'maybe add later'. I really want my lecky bill to be zero averaged over a year. That would be mega. I remember posting such things long before I even had a battery, PV, EV etc. and mocked as the ROI didn't add up. It still doesn't. BUT! Every gas/electric hike makes it more and more viable. I read somewhere ( BBC I think ) that our electricity consumption is set to double by 2050 ( from memory ). Lecky costs ( we will ignore mega gas increases for now! ) will only for the foreseeable future increase. I know it will rain, so I'll buy my brolly now! ? Edited January 13, 2022 by pocster Link to comment Share on other sites More sharing options...
Carrerahill Posted January 13, 2022 Share Posted January 13, 2022 (edited) 18 minutes ago, pocster said: Now this is where I'm confused. My inverter can only ever export 3.6kw. So I could add a zillion PV panels but in reality I need something like SolarEdge to store the electricity . I also didn't realise that I have 2 sets of panels on either side of my ridge and apparently a shadow will 'knock out' the entire ridge. Whilst with solar Edges 'optimiser' one panel in shade will not effect power generation from the others. Not sure of how much the actual benefit would be .... Agreed. I rather export zero at 3p a KW and keep as much as possible for myself rather than buy it back at 5p off peak or 25p peak. The engineer claimed it is possible to 'stop' export via a device that is controlled presumably by the DNO to stop over generation. To his knowledge he hasn't seen one installed on a domestic property yet. Just a few hundred quid apparently... I understand your wait tactic. Problem is ultimately that day will come and by then ( as even now ) demand for batteries outstrips supply. Also I note Tesla for example have increased the price of their batteries - extra money for old rope. TBH he didn't really push the extra PV option it was just a consideration that even if his own wording was 'maybe add later'. I really want my lucky bill to be zero averaged over a year. That would be mega. I remember posting such things long before I even had a battery, PV, EV etc. and mocked as the ROI didn't add up. It still doesn't. BUT! Every gas/electric hike makes it more and more viable. I read somewhere ( BBC I think ) that our electricity consumption is set to double by 2050 ( from memory ). Lecky ( we will ignore mega gas increases for now! ) will only for the foreseeable future increase. I know it will rain, so I'll buy my brolly now! ? You can get a device which some manufacturers call a export limitation system, it is basically a module which sits in before your DB and stops export, you buy it and wire it in and program in a dead stop, i.e. nothing. Each panel is made up of a quantity of PV cells, like a battery, the more you add the higher the output voltage and the more current they can generate, so in a panel you might already have say 80 PV's - when you connect 2 of this same panel together you have actually just linked 160PV cells together. Now if you block the light to 1 cell that cell then might fall below the threshold of incident light at which it generates, it becomes, like a battery, a dead cell and takes the whole connected string of cells with it down to it's level, which in a large string could mean 5 or 6 panels worth. There are options, optimisers and microinverters, optimisers take in each panels output, optimises the generation and adds it to the string, then the single inverter then does it's business as usual. If a panel stops generating due to a shadow or a dirty great crow sitting on it then the optimiser essentially ignores the panel and excludes it from the string. Then there are micro inverters, a box about the size of a VHS tape, maybe a bit smaller, and it has a + and - connection, panel goes directly into it and it has a AC output, you just wire them to a main AC bus or wire them all back to a terminal board etc. at that you can then have your solar monitoring module. The micro inverter is my preference because it makes each panel and MI become it's own little generation plant. A fault on one panel or inverter only takes out one panel. The ROI is getting closer now, my thinking is that we do ROI calcs using the present energy costs, we should be doing them with costs 1-2 years from now, had we all put in solar 2-3 years ago we might be laughing now, but then of course it was more expensive then. I think we might be at the tipping point. Edited January 13, 2022 by Carrerahill 1 Link to comment Share on other sites More sharing options...
Pocster Posted January 13, 2022 Author Share Posted January 13, 2022 4 minutes ago, Carrerahill said: The ROI is getting closer now, my thinking is that we do ROI calcs using the present energy costs, we should be doing them with costs 1-2 years from now, had we all put in solar 2-3 years ago we might be laughing now, but then of course it was more expensive then. I think we might be at the tipping point. 100% my argument. Dread to think cost of electric 5 years from now. My thought on this having just signed a new 1 yr contract with octopus at 5p off peak and 25p peak is what an earth will it be in 2 years? Even off peak will be far more than 5p, let alone peak. Link to comment Share on other sites More sharing options...
Pocster Posted January 13, 2022 Author Share Posted January 13, 2022 Just decided to look at octopus go rates now out of interest off peak 7.5p peak 31.42 So *assume* that's what they need to make a reasonable profit..... So in 12 months I'm going to get bumped up a lot me thinks..... Link to comment Share on other sites More sharing options...
Carrerahill Posted January 13, 2022 Share Posted January 13, 2022 Just now, pocster said: 100% my argument. Dread to think cost of electric 5 years from now. My thought on this having just signed a new 1 yr contract with octopus at 5p off peak and 25p peak is what an earth will it be in 2 years? Even off peak will be far more than 5p, let alone peak. This is where a little EV would be good to consume the energy. Issue is my EV would be away from home during the main sunshine hours 3 days a week. I worked out I could get a little VW EUp on lease for the same money I spend on diesel a month, I considered it, but was put off when I realised I would not get rid of my diesel car, so I would end up paying out more albeit some of my motoring miles would be much cheaper. 1 Link to comment Share on other sites More sharing options...
Pocster Posted January 17, 2022 Author Share Posted January 17, 2022 (edited) DNO unsurprisingly refused my request . But potential installer says solarEdge can. Charge from grid . Wtf ! . New installer says DNO don’t care about how much I draw it’s how much I export . So I’m confused again . Why can’t I just have another PW2 and have a limiter on my export … Edited January 17, 2022 by pocster Link to comment Share on other sites More sharing options...
Pocster Posted January 18, 2022 Author Share Posted January 18, 2022 The more questions I ask the more confused I get “ It is to do with the voltage increases - without export limitation we are only allowed a 1% increase, with export limitation we are allowed a 2.5% increase. In this instance, the voltage rise would be above 2.5% in both cases, so export limitation is not an option.“ I believe the issue is that an export limitation triggered by DNO can take upto 5 seconds to action …. Link to comment Share on other sites More sharing options...
Wil Posted January 18, 2022 Share Posted January 18, 2022 Shirley you can get agreement under G99 to NEVER export, rather than a response to a DNO limitation. Perhaps you're trying to have cake and eat- export sometimes, but not when DNO says no. As I understood it (with your DNO's permission) you could limit or zero your export on any level of panels. You still need to ask first though as opposed to G98 where you can do it and tell them later. as I understand it the inverter just changes the power factor to limit or zero the export of power to whatever you set. If in your case your inverter is under 3.68kW and G98 compliant, there's nothing they can do to stop you connecting? What was your request? Link to comment Share on other sites More sharing options...
Pocster Posted January 18, 2022 Author Share Posted January 18, 2022 10 minutes ago, Wil said: Shirley you can get agreement under G99 to NEVER export, rather than a response to a DNO limitation. Perhaps you're trying to have cake and eat- export sometimes, but not when DNO says no. As I understood it (with your DNO's permission) you could limit or zero your export on any level of panels. You still need to ask first though as opposed to G98 where you can do it and tell them later. as I understand it the inverter just changes the power factor to limit or zero the export of power to whatever you set. If in your case your inverter is under 3.68kW and G98 compliant, there's nothing they can do to stop you connecting? What was your request? Yes . I’m not trying to be greedy lol . In reality zero export would be fine - but in summer might be a bummer - but perhaps that is just tough …. Trying to use summer sun to offset winter costs . Still confused anyway . Afaik I’m only allowed 1 inverter . Tesla has an inverter and SE would require one also . Called SE - some call centre somewhere; he knew less than me ! Link to comment Share on other sites More sharing options...
Wil Posted January 18, 2022 Share Posted January 18, 2022 (edited) The Tesla inverter is only to convert AC/DC for the batteries and back again- irrelevant to the grid. You do still need G99 for grid connected storage, but could limit it to 3.68kW output max (or if they've already said no, go back with zero output). In reality, once you've filled the battery you want to keep it for the dark hours unless you're doing some sort of clever time-based exporting. I just have a 3.68kWp inverter and allow summer excess after the water tank and car are full to go back to grid. Now I have the ASHP, I'm considering more solar to offset their usage! I do have 3phases to go at though. Edit: Actually the Tesla inverter is relevant if it can export and therefore needs to be set to zero export too... Edited January 18, 2022 by Wil Link to comment Share on other sites More sharing options...
Pocster Posted January 18, 2022 Author Share Posted January 18, 2022 21 minutes ago, Wil said: The Tesla inverter is only to convert AC/DC for the batteries and back again- irrelevant to the grid. You do still need G99 for grid connected storage, but could limit it to 3.68kW output max (or if they've already said no, go back with zero output). In reality, once you've filled the battery you want to keep it for the dark hours unless you're doing some sort of clever time-based exporting. I just have a 3.68kWp inverter and allow summer excess after the water tank and car are full to go back to grid. Now I have the ASHP, I'm considering more solar to offset their usage! I do have 3phases to go at though. Edit: Actually the Tesla inverter is relevant if it can export and therefore needs to be set to zero export too... This is what’s confusing me . If my export is capped at 3.6kw regardless of how many batteries I have that’s fine . Spoke to various installers , 10 different answers . Decided to call my DNO directly . Get it straight from the horses mouth tomorrow… Link to comment Share on other sites More sharing options...
SteamyTea Posted January 18, 2022 Share Posted January 18, 2022 I still think that, with special permission from the DNO i.e under G98, it is the generation capacity that is measured. So if you have a batter system that can deliver more that 16A to the grid, you are stuffed, and if you have a PV system as well, you are double stuffed. You could be sneaky and keep adding more capacity with micro inverters. Probably hard for them to detect that easily. Link to comment Share on other sites More sharing options...
Pocster Posted January 18, 2022 Author Share Posted January 18, 2022 38 minutes ago, SteamyTea said: I still think that, with special permission from the DNO i.e under G98, it is the generation capacity that is measured. So if you have a batter system that can deliver more that 16A to the grid, you are stuffed, and if you have a PV system as well, you are double stuffed. You could be sneaky and keep adding more capacity with micro inverters. Probably hard for them to detect that easily. So nothing to do with import / export ? . Simply the amount I *could* generate ??? Link to comment Share on other sites More sharing options...
SteamyTea Posted January 18, 2022 Share Posted January 18, 2022 (edited) 39 minutes ago, pocster said: So nothing to do with import / export ? . Simply the amount I *could* generate ??? They way I understood it, (a decade since I left the industry now) it is a combination of local usage, local generation and main 'large' generation. The 16A limit was put in place as it was a relative safe amount to deal with. Trouble is, because the original FiTs was so generous, and system prices halved in 18 months, more systems where fitted than anticipated. This caused a few problems (down here local grids were soon saturated, even though the main bulk carrier cabling is underused by many MW). I seem to also remember that CHP was limited to 8A, as it could produce that all day long, all year long, but would usually kick in early morning i.e. 5 to 6 AM, when it was of little use as the electricity morning peak is later. Why did you not get 3 phase? As you like wiring, why don't you make an off grid system to run some low powered stuff i.e. lighting and IT. Easy enough to have that switch a mains BMS on if they get too low on energy. You can also dump to thermal storage, even if it is just a couple of storage heaters in the dungeon, if overheating happens, just wear less clothing. Edited January 18, 2022 by SteamyTea Link to comment Share on other sites More sharing options...
Pocster Posted January 18, 2022 Author Share Posted January 18, 2022 3 phase was ( from memory ) 10k Link to comment Share on other sites More sharing options...
SteamyTea Posted January 18, 2022 Share Posted January 18, 2022 Just now, pocster said: 3 phase was ( from memory ) 10k Ask again, they may have put the cabling in. Link to comment Share on other sites More sharing options...
Pocster Posted January 18, 2022 Author Share Posted January 18, 2022 37 minutes ago, SteamyTea said: Ask again, they may have put the cabling in. I doubt it . Surely I could tell …? Link to comment Share on other sites More sharing options...
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