Options please - More Panels or not

Big Lar

Current Setup:

8.6Kw panels, (6Kw Solis 5G Hybrid Inverter, 30Kw Batteries - Located in House Utility) CT clamp on ESB Meter with Cat5 cable to inverter

House and two EV's use around 1700Kwh per month

Production & Usage:

June 2023: Generated 1023Kwh, Exported 81Kwh, Imported 517Kwh

May 2023: Generated 1129Kwh, Exported 30Kwh, Imported 650Kwh

April 2023: Generated 788Kwh, Exported 70Kwh, Imported 1098Kwh

Doubtful electricity prices will ever be as low as they were a few years ago, I can see an end to the Day and Night meter in the next few years, solar equipment seems to be getting cheaper so could probably use more solar if it were generated, problem is that I would not be able to fit any more equipment at the house as space in the utility is limited and I am also considering moving the batteries out to the shed 40m away from the house which is served by a 10sq cable from the CU in the house, I have no problem with room to ground mount panels.

Obviously I would have to install second inverter, anyone got any ideas on if it would be worth my while and what way would I configure things ?

DC999

Ignoring the ‘how’ for now. Start with the ‘why’ install more. You’re still importing a lot more than you generate (fully electric house as you say). Imported ~500kwh in June and that was a belter. So that’s the ‘why’ justification. You’d be right to get more. And that all helps in the winter as could start to run some heating from electricity from solar. I did that last year in a few rooms and reduced gas heating bills.

And you’ve space at home as you said. I think yours is the brill ground mount using telephone poles?? So you can alter the angle on a new one to get earlier or later sun than your current setup (if pure South) – if going ground mount again. On the ‘how to design’, not a clue. Others can chime in.

We can’t bank on FIT rates of course but you’re not even exporting at the mo (only 1-kWh a day). 

Big Lar

Well on the how is where I am stuck also to be honest.

I can put another inverter in the shed no problem but then how can I get new inverter to communicate with original inverter to tell it that we have surplus and charge the batteries or that we are importing or exporting to the grid, the shed does not use that much electricity so a clamp on the incoming supply there is not going to help that much at all.

ColemanY2K

Have you considered how you could reduce consumption thereby reducing the import?

More panels certainly seems the obvious solution but me personally wouldn't have the technical know how.

bullit_dodger

8.6kwp is sizable enough. I've 8.8Kwp myself.

How many panels are you thinking about? If it's just 2 or 4 panels, I'd go micro-inverter route. You could even plug it into a normal 3 pin socket, although I would recommend isolating the panels off on the far side of an isolation switch.

You on a smart meter at the moment?

Buffman

The Solis inverters can be set up to communicate with each other, so you can install as much as you want and set them up to only export the maximum allowed KW. I assume your aim is to get the import-export figures to match a lot more than currently by increasing export and reducing import.

So an easy way to work it is to install a Solis grid-tie inverter and set them up so that your current hybrid is always keeping your large battery topped up and the grid-tie is doing most/all of the exporting.

With the massive amount of space you have I'd be aiming to go as large as possible, if even just to cover the 2 EVs as much a possible.

Another option to possibly consider if you want to go 'super-size' is the Mini-Generation route which lets you export upto 17kw single-phase or 72kw three-phase.

https://www.esbnetworks.ie/new-connections/generator-connections-group/mini-generation

Big Lar

@bullit_dodger I would possible go another 4Kw for the time but would like the option to add on, I looked into micro inverters but not really controllable, have D/N meter at the moment and getting deemed export.

@Buffman I would like to know how to set the inverters up to communicate with each other, I will have another challenge in that the inverters will be in separate buildings but connected to the same grid supply. I don't know about exporting 17Kw, I have an Enhanced supply I think(80A fuse) however 63A on the fuse board so I am thinking that perhaps the cabling from the meter to the board may not be adequate for 17Kw. Another option that I could probably do would be install the inverter outside and I would have a route to bring the AC cable from that to the ESB meter box if that were allowed.

Big Lar

@ColemanY2K Cannot reduce consumption to be honest, house is going here all day, home office with a few PC's and all that goes with it, two EV's of which one does 30km per year

homingbird

I am thinking about getting solar installed but the panel efficiency of solar panels is improving all the time no point ending up with last years old stock when this years panels are 50% more efficient that what worries me.

https://www.youtube.com/watch?v=fFICdZ9I2wg

Big Lar

https://www.boards.ie/discussion/comment/120814652#Comment_120814652

That's a bit like waiting for next years car model, there will always be something better coming along.

idc

https://www.boards.ie/discussion/comment/120814652#Comment_120814652

Also not sure that efficiencies are climbing that fast if a panel that was 20% efficient then the next years panels would be about 30 but thats not the case currently. What you may of seen is panels that were 300W a few years back but now 400 or even 500+ W is the norm. The issue here is that the efficiency hasn't actually massively increased but instead the panels are just getting larger and larger. back 2-3 years ago a 300 W was approx 1.6m x 1 meter with module effiicency of 18.4 but a newer 500W panel now is 2m x 1.3m and module efficiency is only 21.

graememk

The Solis inverters dont need to communicate to export limit. You just need 1 to limit production (well if you have 2, if 3 or more.. well it depends)

Say you set your hybrid to export a max of 6000w

and you put in another inverter capable of 6000,

If both are in full sun, battery is full, the hybrid will shut off/restrict its production to 0 to keep under the 6kw export limit. the other inverter doesnt know about or care of the hybrid. it just generates power.

homingbird

https://www.boards.ie/discussion/comment/120814872#Comment_120814872

So the future is panels getting smaller with higher wattage so you will be able to get more panels on your roof.

ColemanY2K

https://www.boards.ie/discussion/comment/120814373#Comment_120814373

Fair enough. Out of curiosity roughly how many kWh of that monthly 1700kWh figure are the cars contributing to?

Big Lar

https://www.boards.ie/discussion/comment/120815011#Comment_120815011

Lets say I leave the House Hybrid Inverter where it is and in the shed I add a 6Kw non hybrid inverter. I set the House Inverter to 0 export and the Shed inverter to 6Kw export or something like that.

Does the Shed inverter need to be connected to the CT clamp in the ESB meter ? If not will it only confuse the house inverter seeing export when its not exporting ?

idc

https://www.boards.ie/discussion/comment/120815075#Comment_120815075

Long term eventually yes, but thats not whats happening at the moment, the panels are getting larger and therefore that leads to higher wattage (with only small increases in efficiency). If efficiencys actually did improve drastically then maybe yes panel sizes might fall but at the moment panel sizes have just been getting larger -- that works for large scale ground mounted systems, but not so simple if you had to install a 2.5 x 2 meter panel on a house roof.

graememk

https://www.boards.ie/discussion/comment/120815133#Comment_120815133

Shed inverter doesn't need anything, let that do what it needs to do.

House hybrid will do all the limiting by limiting itself.

Eg before export limit

Shed produces 5kw

Hybrid produces 5kw

House using 500w.

After export limit

Shed will keep producing 5kw

House using 500

Hybrid will reduce by 3500 to 1500 to maintain the 6kw export limit.

listermint

https://www.boards.ie/discussion/comment/120815112#Comment_120815112

I'm using around 770 kwh pm with MHRV installed and WFH and kids. Extra capacity is grand but what real consumption measures have you at hone regards to lighting and other draws

Big Lar

https://www.boards.ie/discussion/comment/120815112#Comment_120815112

At a guess both cars are about 600-700Kwh PM, that's based on my 30,000KM per year @ 16Kwh per 100km and then the wife does about 15Km a year although she is heavier on the foot would blow you out of with heat in the car so she gets like 19Kwh per 100Km.

bullit_dodger

https://www.boards.ie/discussion/comment/120814363#Comment_120814363

Another 4Kwp is 10x panels, so a string inverter would be better on that grounds. The reason I was suggesting micro-inverters was one of cost. For 2 or 4 panels, it's (usually) cheaper to buy 2x2 panel micro-inverters ~€150-200ea than to buy a string inverter. For 10 panels though, the string inverter would get the nod I think.

DC999

https://www.boards.ie/discussion/comment/120815503#Comment_120815503

If you have a Zappi you can see the stats in the My Energie Web portal or mobile app for this month, last month...Gives you a sense of historic use.

We use 200kWh a month driving a Leaf like Miss Daisy. About 15000km a year urban driving so slow speeds. So maybe the vars use less than you think.

It's worth a look to see if you could drop usage anywhere alright. Someone else mentioned that. Would save u buying less units on top of your existing large array. Or getting a 2nd large setup.

Big Lar

https://www.boards.ie/discussion/comment/120816611#Comment_120816611

Ahhh

jasgrif11

I'm in a similar scenario. As a reminder here is my setup:

16 X 380w panels (on main house, grant install) on a Solis Inverter - 4.9kw

14 X 400w panels (on Garage, DIY install) on a Sofar Hyd 6000EP - 5.6kw

10 X 405w panels (on ground mount, DIY install) on Sofar grid tied Inverter - 4.0 kw

Total size is 14.5 kw (all 3 inverters and battery are installed in my Garage)

I have a 40kWh DIY battery connected to the Sofar Hybrid and have all 3 inverters connected vi a MYEnergi CT Clamp.

I use approximately 40-45kWh per day during the Winter and roughly half of that during the summer. My house is all electric. Heatpump and 2 X Evs (one is mostly charged at work).

I have additional roof space on my house for 11 panels. This would be an East/West configuration. I originally said I was done :) but now that panel cost is coming down I'm wondering if I should max out and install the extra 11 panels. I would need to install another grid tied inverter (I have an additional consumer unit upstairs in my house) as there is no easy way to route cables back to the garage. This would also mean I wouldn't be able to add the CT clamp and route it back to my MyEnergi hub (I have 2 Hubs connected together as I also have the CT for the Zappi).

Does anyone have a similar-sized system (50+ panels). Any advice?

Big Lar

@jasgrif11 I am still at the planning process so the hamster is still on the wheel here and if the project was to go ahead I would be close to 50 panels.

With regards to the CT clamp I suspect that inverters and My energy use read only from CT clamp so I am considering using existing wifi network with arduino perhaps.

Have you considered that you could have 20Kw being generated at peak times and would the internal wiring be sufficient ? Also what would you do with the excess Solar as I have also been wondering what would I do with the excess solar if the car was not connected so would I perhaps add an additional HW cylinder to heat water for the radiators then I could circulate that around the house rather than the oil boiler firing up.

jasgrif11

I have 3 consumer units (Main, upstairs and garage). All have 63A main fuses. I believe the wiring is fine. I'm a little concerned on the load on the consumer unit in the garage what with having 3 X 32A breakers and the Zappi breaker (should I be?).

I'm less concerned about the excess Solar. This summer the house has been working directly off of Solar, excess tops up the battery (for off-peak usage) and charges the car. I've exported on average 300kWh to the grid for June and it will be similar for July. However, from September onwards will probably be zero export.

I don't have a requirement for additional HW heating as my heat pump with an integrated water cylinder is very good in that regard.

Does anyone else have 4 inverters, even those of you @graememk that are using them for load shifting?

graememk

I'd be concerned about export limiting, not raise any eyebrows/drawing attention to yourself.

As for the garage and the 3 32amp mcbs isn't a concern for me, it's more about load, it's not like there is 3 32 amp loads,

Worst case could be:

The straight inverter just outputs power

Hybrid could draw 5kw, (20 amps if charging from grid)

Zappi drawing 7kw charging overnight.

Unless the heatpump is on that board too?

10-10-20

@jasgrif11, which of your inverters is your exporting inverter and are you on NC6 (ie, already maxed out in terms of the allowed kW)?

Priority wise I presume that the primary consumers go like this: house load -> EV -> DIY battery -> grid export.

I think you're in the almost unique and somewhat paradoxical situation in terms of Winter/Summer as I suspect that you're maxing out the export limit on quite a number of Summer days, while Winter-time you're probably unable to keep up with demand (and hence importing). So is the burning issue here the fact that you have room for 11 more panels 😉 or is it that you want to maximise your Winter generation to eliminate imports?

If you're on NC6 and you're already swamping out the export during Summer then you already know that you're going to have to find another consumer for that excess energy; would you consider an NC7 then and go for that fourth grid-tied inverter? That should free up the Sofar Hybrid to charge-up the batteries and give you a reasonable return on the excess.

10-10-20

Oh and another comment : Ohm's law and the good guidance of circuit theory says that where there are multiple sources of power in a circuit (that being your overall house and garage) that the biggest consumers should be closest to the main suppliers of power and all other sources should be located further out from that point. That might sound obvious but it should be a consideration where you have a "hybrid" or "organic" electrical layout and when you're charging batteries on one inverter and potentially running a heat-pump on a nearby circuit. These would be two heavy loads which cause the largest efficiency losses as they pull power from the furthest points, or worse could in theory overload incoming circuits. In my mind the inverter with the battery should be the furthest load from the heatpump (hence with the highest line resistance) and the closest inverter to the heatpump should be the largest inverter (without a battery). That way the loads are localised to the power sources as best as possible and the line resistances are kept low.

Padre_Pio

https://www.boards.ie/discussion/comment/120814652#Comment_120814652

The general guidance is that you're better off financially when you buy many cheaper, less efficient panels than a few expensive, high efficient panels.

Unless you're stuck for roof space.

jasgrif11

The Heatpump is on a separate board. @10-10-20 yes the priority is as follows house load -> EV -> DIY battery -> grid export. The burning need is to limit the import in the winter, albeit I got the solar bug and only see usable space on my roof :)

10-10-20

https://www.boards.ie/discussion/comment/120893214#Comment_120893214

It might be a separate board, but aren't you pulling power to it from the various inverters across the house?

DC999

https://www.boards.ie/discussion/comment/120893214#Comment_120893214

What about getting the NC7 (and export limit is gone), get a smart meter and get paid a savage amount of FIT. Ok, you can’t count on FIT being there forever. Assuming NC7 is ~€1000, you’d break even after exporting 5000kWh @20c FIT. Still need to check the internal wiring of course.

Bear in mind you have the tax implications too above €200 of FIT per named individual on the electricity bill.

You could be in a difficult position with your home insurance being valid if there was a fire and you were in breach of ESB regs (NC6). Wouldn’t take an assessor much to realise it was a veryyy large solar setup and to check if that was reg. compliant. 

Mr Q

https://www.boards.ie/discussion/comment/120885477#Comment_120885477

What BMS do you use with a battery of that size and a Sofar inverter?

jasgrif11

I think I will look at the NC7 form. Has anyone here done that?

@Mr Q I currently have a Seplos, but it will only work with 550ah. I have ordered a JK BMS and that should arrive later this week. It supports 800ah

unkel

https://www.boards.ie/discussion/comment/120897925#Comment_120897925

What makes you think the JK BMS is limited to 800Ah? Just curious, I can't find that limitation in the spec and my setup is far bigger than 800Ah and working fine with the JK BMS.

Some in here have done the NC7, but if I understand it right, the summary is that the application itself costs about €1100 and that is no guarantee of it being approved. And the only benefit I can see is that you are allowed to export 11kW (compared to 6kW on the NC6)

graememk

https://www.boards.ie/discussion/comment/120899245#Comment_120899245

17kVA or whatever your MIC is.. which is for most people 12.. or even 8! (mine was 8 until i got it upgraded, also was on 10mm2 tails too! 16kVA and 25mm2 tails now :D)

Also allows for export limiting to AFAIK.

I think he means the JK will support 800ah, not that 800 is its limit.

Has your 7p balanced out yet lol. That battery will last forever, never gets too full, never gets that empty.

idc

https://www.boards.ie/discussion/comment/120899554#Comment_120899554

Yes NC6 doesn't allow for export limiting - ESBN just add the size of each and every inverter connected to grid. (which i guess would also include AC connected batteries)

Where NC7 allows for export limitation devices so you could have as many inverters as you wanted as long as export limitation limited output to 17kVA or MIC

unkel

https://www.boards.ie/discussion/comment/120899554#Comment_120899554

At the mo between 3.340 and 3.348V LOL, not too worried about (top) balancing as there will no doubt be one cell the weakest, but it's much of a muchness. From now on for the next few months I won't in practice be able to get it full just from PV and it won't really go fully empty either unless I either dump battery into EVs or crypto rigs overnight

Thanks for the clarification on the NC7. My own supply is 12kVA

idc

https://www.boards.ie/discussion/comment/120899554#Comment_120899554

Is there much work involved upgrading MIC? House is only 8, is this something just ESBN do or likely I'd also need tails upgrade as well?

graememk

https://www.boards.ie/discussion/comment/120900338#Comment_120900338

If your on 8, very likely you'd need tails, and likely a new consumer unit too, esbn sends out engineer to see if anything needs upgraded on their end (they replaced a pole down the road in my case) cost about 1300 ish back in 2020.

May need a new cert for the house, I didn't but ended up getting one anyway

I was doing a few things at once, ev charger, taking power to the yard, new consumer unit,(it was the original one with screw in fuses, no rcd at all), solar [although that's connected to the new consumer unit down there]

I wouldn't do it unless you need more power

jasgrif11

Yep meant JK will support 800ah. I was exploring getting a second Seplos and changing the battery configuration or just going for the JK. JK actually arrived today, so that is a job for tomorrow. Doesn't look too taxing, given all the cables are in place. Just need to extend the wires for from BMS to the battery same as the Seplos.

I've seen the JK in Andys videos, but in person its a much tidier unit than the Seplos

unkel

https://www.boards.ie/discussion/comment/120900614#Comment_120900614

Wait til you try the app. Then you know how much tidier the JK BMS is than the Seplos 😁

Everything is easy to understand. No silly chinglish language used in parameters that nobody knows what the hell they mean, straight forward, plug and play. And robust. And active balancing. And if you bought from Hankzor BMS store, the lads know their stuff. Few small issues I had were easily sorted with their help. The only thing missing is native CAN comms with the main inverters. But this is overrated as every single cheap BMS I have ever seen can't really calculate SOC very well. More reliable to go by voltages...

Big Lar

https://www.boards.ie/discussion/comment/120899554#Comment_120899554

Just on that for clarification I have an 80A main fuse from ESB so am I right in thinking 17kva ?

graememk

https://www.boards.ie/discussion/comment/120901237#Comment_120901237

Fuse in your house is 80A? or in the ESB Head?

generally an 16kVA is a 100amp in the ESB head and 80 in the house, 12 has a 80 ESB fuse and 63 in the house. (thats what the ESB guy told me when they changed the fuse anyway) I have a 80amp MCB which is now in my meterbox [tails are about 5m by the time it gets to my consumer unit]

If you ever switch names on the electric bill, ESBN send you out a "connection letter" stating the MIC

unkel

https://www.boards.ie/discussion/comment/120901308#Comment_120901308

Electrician told me that too. And indeed I do have a 12kVA connection, a 63A fuse in my consumer unit and a 80A fuse in my ESB meterbox, consistent with all you said.

maxymo

https://www.boards.ie/discussion/comment/120901319#Comment_120901319

Yes, I was looking for mine and came across this thread, I went to look into my main fuse and it is 63A, then later remember I had a letter from ESN that received when changed the name of the electric bill and indeed it says my MIC is 12kVA.