Solar for Beginners [ask your questions here]

graememk

https://www.boards.ie/discussion/comment/121248980#Comment_121248980

LFP, The higher cell voltage really only happen at 98/99%

the battery isnt dead at 6000 cycles, It still has 80% capacity,

20%-90% is only 0.7 of a cycle too. I'm all for making the battery work, thats what it is there for.

If you dont need that 10% to reach you to night rate sure, dont charge that 10%, but if that 10% stops you from using day rate, I'd be using as much capacity as I can.

unkel

https://www.boards.ie/discussion/comment/121248980#Comment_121248980

Not necessarily agreed. If going between 0% and 100% saves you say €2 per day (compared to cylcing between 20% and 90%) but costs €1 per day in additional battery wear, you should cycle between 0% and 100%

Do you get where I'm coming from?

For me personally it doesn't play as much because my battery is now huge, 77kWh. It doesn't really get full or empty often. But if you only have a 2.5kWh or 5kWh battery, you'd want to squeeze every bit out of it, if that gives you a high FIT or even better, if it prevents you spending upwards of 30c on a day unit of electricity

AmpMan

https://www.boards.ie/discussion/comment/121248976#Comment_121248976

if you put in any azimuth and hit go then scroll down and hover over the outline of the horizon it's easy to understand.

micks_address

https://www.boards.ie/discussion/comment/121249086#Comment_121249086

thanks so northwest is 135ish?

10-10-20

https://www.boards.ie/discussion/comment/121249085#Comment_121249085

You're wearing a financial hat and looking at the battery as an asset and applying amortisation over the expected lifetime. I wear a technical hat and I see the battery as an object with needs and a useful lifetime, which I'd aim to extend. So different view-points. 😄

https://www.boards.ie/discussion/comment/121249070#Comment_121249070

Alright, didn't recall the charge-curve for LFP. Get you fully. I still wouldn't flat-line it below a low percentage though.

10-10-20

https://www.boards.ie/discussion/comment/121249119#Comment_121249119

"relative to the direction due South. -90° is East, 0° is South and 90° is West."

So NW would be +135 degrees roughly, yes.

NE would be -135 degrees roughly.

unkel

https://www.boards.ie/discussion/comment/121249151#Comment_121249151

Yep that's exactly it. Reminds me of the conversations I had in the early days of boards where I would typically buy a cheaper CPU for my PC and then overclock the bejaysus out of it. Basically saving a fortune on not having to spend the extra money on a much more expensive CPU

A lot of (technical) people couldn't get their head around it. But, but, the life span of that expensive CPU will be less, will it not? Yes of course it will. Life expectancy probably down from 10 years to say 3 years. But after 3 years the CPU is pretty much obsolete anyway, worth only a fraction of what it cost new, no matter if it was babied all its life or not

bullit_dodger

https://www.boards.ie/discussion/comment/121248969#Comment_121248969

100% agreed - I go from 4% (the min it lets you) to 100%. Have been doing it pretty much every day since I got it. With the automation I have it either gets charged via night rate, or solar, but it'll be charged one way or the other every day. As a result, I've probably knocked 800-900 cycles on it. Have noticed a slight detoriation, but it's minor .... low single digits (maybe 2-3%), and totally happy with that.

unkel

https://www.boards.ie/discussion/comment/121249583#Comment_121249583

Now is the very time for the quickest payback too. We enjoy a very generous, pretty much tax free FIT (the pinergy one is over 27c incl VAT) and our batteries for some of us, allow us to only buy supercheap night rate electricity, pinergy rate is 5c incl VAT

Those days won't last forever and batteries are gettng cheaper. I'm usually a bit too optimistic, I've been buying LiFePO4 batteries for not much more than €100 per kWh and until recently was expecting that to be down to €50 within about 2 years because of NaFePO4 battery availability. That is likely 3-4 years away at least. So as long as our batteries make it to around then, let's put them to work for us. Our investments were heavy enough. All good for the planet but most of us simply can't afford to have a pay back period that is too long.

bullit_dodger

https://www.boards.ie/discussion/comment/121249708#Comment_121249708

As I'm still on the old deemed export, I haven't gotten into the "charge at night rate to dump during the day" yet. I do have a 8.2Kwh battery, but unless I'm fairly stingy with my power use, these days it just about gets me to 10-11pm. I do have a ME3000 for a 15Kwh DIY purchased - just a little short on €€€ for the cells/balancer/box/etc at the moment. Checked behind the cushions on the couch and everything!

Once I'm on the smart meter, I'll have to work out some new automation routine to "dump to grid" whatever is left in the battery an hour before daytime ends (making sure I have enough). With a bigger battery than my 8kwh, the options are better of course.

To be fair, deemed export it was a decent enough compromise for ESBN to come up with as they were rolling out the meters. Can't complain too much.

niallo27

Hi all, I'm new to all this, I'm looking at getting panels in, I already have panels for the hot water which are great in fairness, only have to stick gas on for 20 mins in winter to get a full tank. My question is would I need an Eddi converter and what exactly would happen the excess power in summer if I didn't have a battery. Apologies if its a stupid question.

graememk

https://www.boards.ie/discussion/comment/121252483#Comment_121252483

Whatever you don't use, gets exported and you get paid for that export.

I wouldn't get the eddi, your hot water is already covered. (And in the winter there isn't much excess)

elgicko

Hi folks,

Question about solar clippings what happens if I don't want to export to the grid?

Let's say I am satisfying my current power requirements, my battery is full, hot water from diverter is done and I am generating excess power, where does it go, is it dangerous?

Can anyone explain this??

Thx

graememk

https://www.boards.ie/discussion/comment/121255301#Comment_121255301

PV is not like a wind turbine.

Simply, If the power is not used, it is just not generated. A panel can sit in full sun but doesn't have to generate any power. It sits like a battery, ready to supply power if power is drawn.

Solar clipping is actually when you have say 8kW of panels on a 5kW inverter, on a really good day, you may see the peak of 5kW being generated at 11 am and flatline until 2pm, this the inverter limiting generation.

On a grid tied system, to not export, the inverter needs to restrict generation. Otherwise it will be exported.

slave1

https://www.boards.ie/discussion/comment/121255301#Comment_121255301

and it's not dangerous, it's just power flowing the other way through the same cable feeding your house, these cables are much higher rated that what your panels/Inverter can produce

elgicko

https://www.boards.ie/discussion/comment/121255444#Comment_121255444

Cheers slave1, makes perfect sense!!

Ginger83

I watched the video to charge the battery from the grid and have a question. On the information screen charge limit is 50.0A and discharge limit is 40.0A but on the screen to charge from grid the charge and discharge limit are both 50.0A. (6kw inverter)

Is this correct? I don't want to do something silly.

20231018_215232.jpg

20231018_215440.jpg

con747

https://www.boards.ie/discussion/comment/121256927#Comment_121256927

Not sure about the amps but AFAIK you only set discharge if you are selling back to the grid, otherwise set it to 00.00 I think or it will just dump it to the grid. It's fine if on a very cheap night rate and selling it back a lot higher.

Ginger83

https://www.boards.ie/discussion/comment/121256957#Comment_121256957

Thanks Con. Is your charge and discharge limit both at 50.0A?

I wonder how long it takes a 5.1kWh battery to charge from 20% to full

ratracer

Hi folks,

Coild some of the knowledgeable folk on here advise on my proposed system. I’m planning on having approx 7kw system on an E/W split, with a 5.3kwh battery.

I’ve only ever been on a 24hr Electric Ireland tariff.

I have a smart meter fitted, so plan to use on of the smart tariffs to charge the battery. How much charge is it likely to get in the two hour low cost window?

Should I opt for an Eddi for hot water, or just use an immersion timer on the cheap rate also to heat the cylinder?

Should I be putting optimisers on the panels? None of the installers that quoted me even mentioned them, but shadow is not an issue on either of the aspects.

I’ve tried to figure it out a bit, but the sheer volume of info available is a bit confusing!

TIA! 👍

unkel

How quickly your battery charges depends on how powerful your inverter is. I presume about 5kW, so it would charge your battery from empty to full in 1 hour

don't get eddi, just use cheap night rate to heat water. Anything from your PV you don't use during the day, will go to the grid and you will get paid for it

No shadow => do not use optimizers

con747

https://www.boards.ie/discussion/comment/121260437#Comment_121260437

I don't charge off the grid so unable to help. @unkel mentions a bit about it in the post above and could maybe advise the best settings. I think you have the Solis 6kW inverter and 2 batteries? If someone can advise you regarding the best way to charge them.

ratracer

https://www.boards.ie/discussion/comment/121260541#Comment_121260541

Thanks Unkel, I’ve been a couple of weeks trying to research those answers, with no clarity!! 😬

I know it’s not the ideal time of year ( for PV generation), but I’ve been putting if on the long finger for most of this year, so it’s time to bite the bullet. Maybe an EV will follow on in time! 🤷‍♂️

18 panels is my max roof space ( 10E and 8W), gonna start with the 5kwh battery, can always add more down the line if its working out well. Average 5,000kwh annual use here.

Ginger83

https://www.boards.ie/discussion/comment/121260541#Comment_121260541

Hi unkel could I get your opinion on #2178 above?

unkel

https://www.boards.ie/discussion/comment/121260597#Comment_121260597

I never had a Solis hybrid inverter, but plenty of people on here do, there's even a dedicated Solis thread about them, ask there and I'm sure someone in the know would answer quickly!

unkel

https://www.boards.ie/discussion/comment/121260595#Comment_121260595

E / W system is ideal for self use! Best of luck with it, and keep us updated. Might not be the worst time of the year either as installers might not be as busy and might not be as expensive as in spring. I'd say next spring will be mental for PV installs as it is getting into the mainstream now, prices of parts are cheap, zero VAT, generous subsidy on the install and very generous fit in tariff combined with the rollout of the smart meters

Perfect storm! You'll be happy you had yours done before that kicks off!

con747

https://www.boards.ie/discussion/comment/121260597#Comment_121260597

Have a read of the first page or 2 here https://www.boards.ie/discussion/2058212281/solis-hybrid-charge-battery-using-night-rate/p1

Ginger83

https://www.boards.ie/discussion/comment/121260641#Comment_121260641

Thanks i think we have it set now

alfa_aficionado

https://www.boards.ie/discussion/comment/121256927#Comment_121256927

Unless you want to sell back to the grid I would set the discharge limit to 0.0A.

My charge limit varies according to how much I want to put into the battery; you can roughly multiply the charge limit you set by 50 to get the charging rate in kWh, e.g. a limit of 50.0A roughly gives you 2.5kWh.

graememk

https://www.boards.ie/discussion/comment/121261048#Comment_121261048

As long as the times are 00:00 -00:00 it won't do anything