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Solar for Beginners [ask your questions here]

AckwelFoley

Hello. I've been reading through the PV threads here and there's alot of information. Some a little confusing if you're not familiar with the units and terms

1kwh is 1 unit of electricity, 1 payable unit of electricity and what a 1kw heater would use in 1 hour of use?

A 5kwh PV system is what that system theoretically can produce in 1 hour of sunlight depending on panel efficiencies and actual sunlight?

I've no idea about batteries however other than I know they're costly and probably not worth the payback?

I'm not familiar with measurable terms, but what size batteries would be needed to store average daily excess? Or is it more cost effective to leave it out and use night tariff

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testtech05

https://www.boards.ie/discussion/comment/120631838#Comment_120631838

Thanks a lot guys, makes perfect sense when you see it explained like that, I really appreciate it!

Now to see if I can free up the funds to add a battery (5kW) for a start to add the setup.....On that note do people recommend putting the battery in straight away if you can or waiting until you get a handle on your generation v usage etc before adding it in?

bullit_dodger

https://www.boards.ie/discussion/comment/120631966#Comment_120631966

So the community would be split on batteries, with good reason. Couple of years back it 100% made sense to get a battery and a reasonably decent sized one at that. 5Kwhr or even 8-10Kwhr would do well in virtually every household. Nowadays with FIT it's a little less clear (the math that is) on payback timelines for batteries.

Personally, I'm of the opinion of generally being positive about them. I think every household (with more a nod towards being environmental rather than fiscal) should have a 5kwhr battery to help "smooth the load" and minimise your day usage ... such as when you turn on the washing machine but the sun keeps popping in/out from behind clouds. Have to say though that the math on them in terms of breaking even isn't what it was. Back 2 years ago we also had a €600 grant for a battery too.

The priority though should always be panels and then panels, and followed lastly by panels. Maximise your roof. Drop the battery, Eddi, etc if it means more panels. Honestly, if this is the only thing you take away, it's sage advice. I max'd my roof (for the SEAI grant) and then added some more after and don't regret doing that.

hexosan

any issue with 12 jinko 425w panels VoC of 38v on my south and on two smaller west facing roofs I can fit another panels 8 panels. Total System size would be 8.5kw would this be ok split between the two strings on the Sunsynk 5.5kw inverter. The inverter can take between 450-500v per string so I’m covered on the volts.

I understand I’ll suffer clipping on some of the sunnier days. More interested in the issue of having too many panels damaging the inverter.

bullit_dodger

12 might be pushing it on that south string. The problem is that while 12x38v = 456v and you would think that it's fair to say that it would be within limits, but the voltages stated are typically done at "standard temperature". This is either +15c or +25c. (I can't remember which)

On a cold day with bright sunshine you could see the panels beat that 38v per panel, to 40-41 sometimes. So you might be there on the edge so to speak with 12 panels of 38Voc. Be interested to hear the thoughts of others though.

whatawaster

Looking for some advice/guidance -

We are in the process of buying a house, which has 11 solar panels, I believe they are 300w panels.

There is a Solis inverter and there is a Pylontech US3000 battery, which google tells me has a capacity of 3.5kWh.

There is something called Solar iboost+ next to the hot water cylinder.

House has a smart meter installed.

We have an electric car (28kWh Ioniq) but there is no charger installed at the new house, so first priority will be getting one in.

Questions:

- Do we need to ask current owners for anything, like is there an app to control these things that we will need access to, or is all that easy to reset when we move in.

- If we install a car charger (Zappi, for instance) is there anything else we need to make full use of the panels/battery to charge the car

- In our case, would it make sense for us to go with a smart plan with much cheaper electricity for a few hours overnight, and use that window to charge the EV and the battery?

- Any other advice etc in order for us to make the most of this setup?

Thanks in advance for your advice

unkel

Good idea to ask the current owners to demo you the full system and to ask for their help with any apps.

Does the house have a smart meter already? If so, you can go with the best smart plan that suits your needs. Even if you have only a 3 hour slot in the middle of the night, that should be plenty to charge both the US3000 and your Ioniq, but you might have to plug the car in more often than you do now

con747

https://www.boards.ie/discussion/comment/120634381#Comment_120634381

Get the installers details and find out if the warranties are transferable and when was it installed.

whatawaster

https://www.boards.ie/discussion/comment/120634514#Comment_120634514

Yeah there is a smart meter.

Current house has an untethered charger and it's bit of a pain taking the cable out of the boot and putting it away etc. Planning on getting a tethered cable for the new house making it more convenient and not much of a hassle if I've to charge more often. Though to be honest, I don't do much mileage, so i'd guess 2/3 nights a week would suffice for my normal usage.

whatawaster

https://www.boards.ie/discussion/comment/120634587#Comment_120634587

Installers name (local company) and installation date (October 2020) were labelled on the equipment, so I will definitely contact them. Thanks!

unkel

https://www.boards.ie/discussion/comment/120634704#Comment_120634704

Yep tethered really is a no brainer unless your OCD is to such absurd levels that you can't stand the looks of a cable somewhere on your wall 😂

Finochet

If I don't go with a battery ( the economics don't stack up @€4K for a 5KW battery.- Difference between Night and day rates is c.21. thus filling it from solar will only save €2 the next day or €1 if filled from.grid at NR.) how do I ensure what's produced by PV is used? How do I know if there is enough to run say dryer and washing machine,electric shower etc. during the day if I don't want it having to switch mid use to expensive grid Day rates?

redmagic68

https://www.boards.ie/discussion/comment/120636226#Comment_120636226

What you’ve just outlined there is one of the best reasons for a battery. It acts as a reservoir to balance out your day time usage against production drops with clouds etc. you may produce 20kwh in a day in a 5 hour period then much less at another time. Without the battery it can be feast or famine. Others will say rightly that this is balanced out by the fit payment to some degree.

however if on a day night meter and calculated fit a battery is win win.

hexosan

Any issues with overheating having 8 4mm solar cables in the one 32mm conduit duct or should they be split between two ducts

unkel

https://www.boards.ie/discussion/comment/120644061#Comment_120644061

Should be fine. Single strings only get up to about 10-11 amps, which is nothing with the big 4mm2 core and thick layer of insulation. I've never felt any solar cable that was noticeably warmer than ambient even

10-10-20

https://www.boards.ie/discussion/comment/120644061#Comment_120644061

Just be aware that there are limitations on this and you're right to ask.

https://www.doncastercables.com/technical-help/1

A standard 4mm2 cable clipped to a wall or in open-air might be normally rated at 37A, but when enclosed in an insulating environment that same cable could be de-rated to 26A for example.

unkel

https://www.boards.ie/discussion/comment/120644433#Comment_120644433

Solar PV in a single string is only about 10-11A. All 6kW and under single phase string grid tie inverters for sale in Ireland that I'm aware of do not allow paralleling of PV strings into MPPT inputs. So it really shouldn't be any issue.

graememk

https://www.boards.ie/discussion/comment/120644433#Comment_120644433

Also a factor is the temperature rating of the insulation too,

That's how the jk bms can get away with 16mm2 on a 200A bms, the insulation can handle the heat.

unkel

https://www.boards.ie/discussion/comment/120645920#Comment_120645920

Well it's actually 2 * 13mm2, so more like a single 25mm2 or 35mm2 cable. But yes your point stands. Those cables don't even get hotter to the touch than my 70mm2 cable strangely enough.

10-10-20

https://www.boards.ie/discussion/comment/120644464#Comment_120644464

Yes correct, but there are limitations and users need to be aware how these are calculated as some may be tempted to use Y or paralleling connectors for multiple panels. The "shure it'll be grand" validation method won't hold up too well if somebody's rafters catch fire in the future. Plus, there can be voltage-drop concerns (efficiency losses) with longer cable runs which can be optimised by moving up to the better rated cables and that's also covered in that link. Agreed?

unkel

@10-10-20 - Agreed with all of that!

10-10-20

https://www.boards.ie/discussion/comment/120528776#Comment_120528776

I just got OpenDTU working on self-assembly kit which connects into my two Hoymiles microinverters:

https://shop.blinkyparts.com/en/OpenDTU-Your-evaluation-for-your-balcony-solar-system/blink237542

It connected into HA using MQTT in the click of a mouse. Brilliant!

Hellrazer

Probably a stupid question. But tried to submit a meter reading tonight to BG and its said "you dont need to submit readings anymore as you have a smart meter installed and we will get teh readings from Esb networks.

All well and good but on the Esb networks page there are no meter readings shown since the smart meter was installed - I do not want another estimated bill.

Should I just text one in or send by sms?

Anyone have any experience on how long it takes for BG to star getting meter readings from ESb networks?

graememk

https://www.boards.ie/discussion/comment/120655115#Comment_120655115

You can submit directly to esb networks

https://www.esbnetworks.ie/submit-a-meter-reading

con747

https://www.boards.ie/discussion/comment/120656103#Comment_120656103

Didn't know you could submit it direct to ESBN, I usually just ring up B/G if the online meter reading won't work.

ELM327

Ionly ever send readings in to ESBN. I get the same message from energia saying I have a smart meter - even. though I dont!

JayBee66

https://www.boards.ie/discussion/comment/120656103#Comment_120656103

Once you have a smart meter installed you will get the following message on ESB Networks...

and no option to submit a reading.

When the former meters are a thing of the past you can only hope that, as with the UK and the Netherlands, agile pricing will be introduced. That will be the only way to game the system. You get a battery, you weigh up the good and the bad with FIT and tariffs and then you feed in power from panels and batteries as and when the market is in your favour. A nice little optimisation problem, if it comes.

unkel

Indeed @JayBee66. I posted up something very similar in another thread on the forum a few minutes ago. The holy grail in the transition to renewables is grid stabilisation / backup with batteries. Those that invest heavily in that, should be and will be rewarded.

Hellrazer

https://www.boards.ie/discussion/comment/120657117#Comment_120657117

Yep thats the message I get - All well and good but there have been no readings logged on the ESB Networks page since the meter was installed- it shows loads of older readings going back 2-3 years but nothing since March 15th.

So unless its updated in the next couple of days Im going to get an estimated reading and since Ive imported less than half of what I used to an estimated bill is going to be wildly over estimated.

Ive worked it out based on solar use etc and my bill should come in a third of what it was before the solar was commissioned - nice enough saving there but if its estimated Im going to be pissed!!!!

BTW this will be my first full billing period with solar over a 2 months cycle.

bunderoon

Anyone use or have experience with Solax Inverters?

Wonder if they are reliable?

graememk

https://www.boards.ie/discussion/comment/120657922#Comment_120657922

If it is estimated, give them a call and have the readings handy