Random Renewables Thread

The devils

Hi guys

Any comments appreciated

1. 1000 euro to spend on extra bits for solar.

2.Also I have 2 puredrive 5kw batteries (should I sell and replace with 20 kw of different model) ordering them from China and wait months?

Tks happy new year

con747

...

tech

Happy New YEar All!

System

This discussion was created from comments split from: Domestic Solar PV Quotes 2024 - No PM requests - See Mod note post #1.

Jonathan

Happy 2024 everyone!

staples7

New house going up a bit away from me, would anyone know why they would put hot water panels rather than pv panels in a new build nowadays? In a bad spot too for pv down the line. Which is otherwise a great roof for solar

haven’t seen this before and just wondering

deezell

https://www.boards.ie/discussion/comment/121556300#Comment_121556300

I don't think thermal solar is written off just yet. It's very efficient, benefiting from infrared spectrum (heat radiation) as well as the direct visible light. Less complex path to hot water, though you do need a small amount of electricity to operate the fluid pump.

There are panels being made which can combine both PV and thermal I've read somewhere. could be beneficial by keeping the pv part cooler.

You don't need many thermal panels either, for HW output, 2 or 3. They became a bit expensive to install as trade costs soared, but perhaps that might make them affordable as a plug in to a new build.

Happy 2024 Heating to all btw. If only there was a way to renew these old fossil bodies a bit...

graememk

Thermal is still king for heating water, although retrofitting them can be a hassle, usually need a new tank, and pipes from the roof can be a hassle.

They also could be the thermodynamic panels not straight solar. which are heatpumps.

Although I'd agree for a new build, much easier to route pipes.

We've got PV on the brain but I'd agree its a missed opportunity.. unless they are going ground mount/ on the garage.

bullit_dodger

I dunno. It could be that simply since I've more knowledge in the electric space, I see PV panels as the far easier option than routing pipes, water pumps, heat exchangers, gycol replacement etc That's not to say I think thermal panels are bad or anything - just seems "more work". Maybe I'm wrong.

I know many people here have them (thermal) for a decade or more and they're still doing what they were installed for and have more than paid for themselves. If anyone has one and can share some real life data that would be interesting. I'd be curious to know how much of the year you get HW out of them. Feb-Nov? I guess you probably get "some" heat even in winter? Might raise the immersion tank 10-15C ?

bullit_dodger

Haven't swung by this lads Youtube channel in awhile, but I see he's got a new project that he's just completed. Great watch.

Powering An Old Mill - 1.5 Kw Lake District Overshot Waterwheel Project Part 1 (youtube.com)

graememk

https://www.boards.ie/discussion/comment/121557159#Comment_121557159

I've thermal tubes, on sunny winters day I do hear the pump kicking in. But same with PV.

Grand intentions of puttin a flow meter in the loop and doing a kWh calculation. But work great in summer.

https://www.boards.ie/discussion/comment/121557166#Comment_121557166

I've only recently come across him.

He's made is own wind turbine. From scratch, literally built the motor! Even hand carves his own blades.

Smart fella.

DC999

https://www.boards.ie/discussion/comment/121557159#Comment_121557159

@Jonathan, do u have any stats on your solar thermals? I'm curious too on the stats. I only know about PV.

bullit_dodger

10-12 Years ago, thermal pipes really were the only viable game in town. I'd imagine the cost has remained fairly constant on them since? They are 2-3x more efficient in capturing the sun's energy for water heating than the same area in PV. Since then though, PV panels have some down some 90%. You'd wonder why builders continue to put them on there?

Solar (photovoltaic) panel prices (ourworldindata.org)

Again, that's not to knock them - they do a job and they do it well, just curious

Jonathan

https://www.boards.ie/discussion/comment/121557159#Comment_121557159

Haven't got a flow meter installed but here is a graph of pump daily running hours Vs PV generation (not sure what happened on 1st Nov. Obviously an error). Both tally fairly well. Don't have long term stats on cylinder temps but it isn't doing a whole lot these days, nor is the PV mind you.

paulbok

Re: minimising clipping during summer sunshine

Has anyone set their battery's to only charge to say 50% in the morning and then begin exporting, enough to have a reserve in case of high usage demand, but capacity left to soak up any excess > than what your inverter is allowed export, around midday when clipping is likely?

It'd take some management to do I'd guess, needing rules setup for managing charging/exporting based on the solar forecast for that day.

unkel

https://www.boards.ie/discussion/comment/121581791#Comment_121581791

You could do that, or rather then base it on forecasts that might be wrong, you could do it after the fact. Wait until the PV for the day is over, then assess what you have in the battery and then dump into the grid what you don't need. Of course you will have more efficiency losses this way.

graememk

https://www.boards.ie/discussion/comment/121581791#Comment_121581791

I understand What you are thinking of, The inverter is limited to a max output (leaving the inverter) to 5kW, But it could charge batteries at 1-2 kw but still output 5kW.

Ive done it, But its in nodered, and I'm controlling the max charge current on my bms to do it. (had to add that functionality to the ZevaBMS I have)

Should be able to make it a bit more portable using the sunsynk add on as that has all the variables you need is there, (grid/inverter power, SOC, battery power, and battery voltage(as your looking to control power, you need to have the voltage for the amps, and you can change the charge amps on the sunsynk)

General gist of the code is, possibly try and keep the amount of power leaving a 5kW inverter, to at least 4.5kW so we have room to work in.

Allow the battery to charge more and more until the power leaving the inverter is less than 4.5kW

paulbok

https://www.boards.ie/discussion/comment/121582344#Comment_121582344

Yeah that's what I'm looking to do

Currently have a backwards spinning old meter but am due a smart meter install soo, already delayed it last October. So planning for life with charging the battery at night etc.

The meter only caught up with my reported usage (April value plus a couple of units each month) mid December. That and having essentially nett usage off the grid has been worth a fair bit, so want to max my FIT once on the smart meter, to minimise the inevitable bill increases.

So my plan is so far;

1. Charge battery at night, use during the day as much as possible. Even in the summer it makes sense to put say 1kWh into the battery to fill the gap from when the battery filled by solar empties and morning solar can cover usage.

2. Minimise clipping as above, so will export a little more early on good day, charging up during the clipping hours.

3. Toying with switching off the Eddi (except for during point 2. ). Oil is cheaper to use so will make more off FIT. Also weighing up majorly reducing turf use in the solid fuel stove during the winter and upping oil use anyway.

Had planned on adding 2 extra panels on a micro inverter this year, but have other pressures on the finances coming up, so it'll be unlikely.

DC999

https://www.boards.ie/discussion/comment/121582574#Comment_121582574

If you have 2 ports free on the microinverter and there is a second MPPT available you can buy old ones on donedeal or adverts. Then they won't impact the output from the newer ones there already.

They appear every so often when people upgrade.

bullit_dodger

https://www.boards.ie/discussion/comment/121582574#Comment_121582574

I think first you need to have a look at the actual clipping involved from your historical data. People on here (and I was one previously) always think "Ohh clipping is bad, your wasting soo much stuff". But the reality is that is actually only a small fraction of your overall production for the year. Sure people with 8-9Kwp in panels on a 5Kw inverter may see it a bit more, but to be fair, they are the edge cases. Most bigger installations people have will have 6-7Kwp on a 5Kw inverter. I've 6.5Kwp on a 5kw myself and my all time max production (which will be same date for many people here) was June 3rd '23. Curve for that .....

The issue is that of course my 6.5Kwp in panels were being blasted by the sun and (I'm guessing) were 60-70C or more, and panels like to be cold for efficiency. So even on my all time greatest day I never saw clipping with 6.5Kwp with 5Kw inverter. I've an E/W split, but in June with the sun nearly overhead, it doesn't matter that much.

If we do a thought experiment though, and move that curve up to say 6kw production (where I'd be "clipped" to 5k) , I might lose 1Kw production for 3-4 hours. Now considering the production for the day was 40kwhr, that's like a 10% loss.

Ok, 10% is a lot you might say. But this 10% was on my all-time greatest ever day, over 3 years. Sadly those days don't come along too much. They certainly don't happen in the middle of Jan :-)

So, and everyone's case can be different, have a look at your historical data and see if you can gauge how much your ACTUALLY losing. You might find it's 100-200Khw a year or something, which at €0.20/unit...well people will have to do your own cost analysis and see how much you want to spend to save it.

Disclaimer: I don't always go on ROI myself, it's a hobby/efficiency optimization problem for me - but just saying.

twitcherdub

Hello all,

Looking for some advice. Currently have 14 panels split ESE/WNW evenly. 5kw Huawei inverter.

Looking to add another 4 to south facing roof. Hope I can add the panels, get the optimisers I need(don't have any currently) and get them installed for under 1500 euro.

My questions are:

Will I get any benefit from the optimisers just by having them?

I take it I should put them on my ESE string and couple with my south facing new panels?

Do I need to do anything other than get them hooked up? They are Huawei 450 P2 optimisers with.

Is it worthwhile proceeding with the additional panels?

Should I consider a battery? Am I restricted to just a Huawei battery? Seems to be expensive if so , the guts of 4000 euro.

Thanks in advance for any replies and advice/suggestions

Boscoirl

Installer Rant(wont name names, but i know of a few people where who he did work for) just need to vent :D

Got panels installed in April 21, at the time the installer suggested the said they would fit 11 panels on my garage, that work with in the SEAI Guidlines, then install 3 more once the grant cleared. due to the design of the roof on the garage putting panels close to the edge wouldnt cause an issue.

That was agreed and paid for. fast forward almost three years of me constantly trying to contact him to arrange the last few panels( in the middle of this his **** up with the grant paperwork meant that I had to appeal with the SEAI to get it paid which delayed me getting the grant money for about 4-5months). the times he did get back to me it was always sure, I'll be in your area in the next few weeks we'll get it sorted. etc, then he'd go to ground again. at this stage I had said i would purchase extra batteries to incentivise him turning up.

Finally before christmas, we sent him a mail stating that we needed him to sort it asap or we would have to take further action, and we were promised a call in the first week of Jan. which as you expect we didnt get. after another mail, we are not getting the reply, as it doesnt fit with SEAI guidelines he can not carry out the work etc and will refund the panels. and while he is technically correct(even though he was the one to suggest it). its a pathetic and cowardly reply. would have much more respect for him if he came back and said the real reason in that it wasnt worth his while fit 3 panels when he has plenty work lined up.

While the original quote was competitive, the overall ordeal has left a bad taste in the mouth, wouldnt recommend him to anyone.

KCross

Tell him the refund you want is not the cost of 3 panels but the cost of installing 3 panels. Very different numbers!

SD_DRACULA

https://www.boards.ie/discussion/comment/121590761#Comment_121590761

I find that getting extra panels installed after the main job is never worth it for the installer, can't charge you too much and after he pays the guys putting them up probably nothing left.

I also did another two expansions after my main install and the way I was able to get them over was to buy the gear myself and then he would send the roofers over to me when they either finished early or some job got cancelled and paid these guys directly so everyone was happy.

But you need to be dealing with a decent installer that is willing to do it.

Boscoirl

the nature of roof means its very simple to put the panels up, its an almost flat galvanised roof, so wouldnt need roofers to get the panels up.

bullit_dodger

https://www.boards.ie/discussion/comment/121590501#Comment_121590501

Unless you have shading, optimizers will do NOTHING for you. In fact, with zero shading.....the optimizers will actually leech off about 0.5%-1% of your production. It's a question of good naming if you ask me. "Optimizers" sounds like it will improve things, so people are always on the look out for things will will give them more umphf - but the reality is that they won't, and at €50 a pop, you might spend €500 or so, to find out you have no bonus.

Even with shading, there are good arguments to not get them and slap some extra panels up (assuming you have room). Only time it's a certainty that optimizers are worth it, is if you have an array split over multiple roofs. So I'd avoid then unless you have some specific reason to get them.

As for adding panels - the general vote would be to put the 4 panels on your ESE. Depends a little on your situation, when you use power etc. Without a battery if you use power in in the evenings, you might find that adding them to your WNW is a little better. Sure, they wont' generate as much power as the ESE (probably 10-15% less), but you'll get good production from March-Sept and if your using power in the evening more than the morning, that might work in your favour.

Could also just do 3 and 1 ..... or split 2 on each I guess. I wouldn't over think it though, adding panels is the main thing.

10-10-20

https://www.boards.ie/discussion/comment/121590501#Comment_121590501

I'd put the four new panels on a microinverter otherwise you're mixing orientations on the same main inverter input. This one for example:

https://www.hoymiles.com/product/microinverter/hm-1200-1500-eu/

The devils

https://www.boards.ie/discussion/comment/121591999#Comment_121591999

Would you use the micro invertor on 4 x panels (1600w total) ?

10-10-20

https://www.boards.ie/discussion/comment/121592055#Comment_121592055

On a mixed orientation system it's detrimental to add a third orientation when there are only two MPPT's. Even if you tried to manage it by adding optimisers then the losses incurred by using those would mean that the system becomes ineffective as the optimisers will trim either the 7 panels (split from the 14 over ESE/WNW) or the 4 new ones (pointing South).

By using an additional microinverter you increase the power returned to the house and if a battery was fitted to the main inverter then the inverter would compensate and charge the battery off the existing attached panels while the microinverter is powering the house load. No faffing. The only limitation would be whether the installation was still under the export limit for the NC6 really.

The devils

https://www.boards.ie/discussion/comment/121592143#Comment_121592143

Thank you - its on a shed south facing

3 at the top and 1 left bottom

"The only limitation would be whether the installation was still under the export limit for the NC6 really." I have export set up - NC6.