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Solar for Dummies.



  • Registered Users Posts: 1,476 ✭✭✭ MAULBROOK

    OK i might be able to help. first things first, don't over think it. Solar PV can do many things to help but first you need to get some quotes to under stand the costs.

  • Registered Users Posts: 1,476 ✭✭✭ MAULBROOK

    Where are you located as we might be able to point you in the right direction so you dont get ripped off.

    That menu of prices reminds me of a poor restraint in Spain and not for the right reasons.

  • Registered Users Posts: 172 ✭✭ harderthanf

    This is interesting. I've a 6kw inverter on an 7kw array. I am thinking of adding a battery but was thinking I'd need to swap out the inverter for a hybrid. Can you explain a bit how you have the two inverters and battery setup?

  • Registered Users Posts: 2,971 ✭✭✭ graememk

    The storage inverter is just connected to the consumer unit like the solar inverter.

    It has 2 cts one for the solar and one for the grid. (Only the grid one is needed)

    It monitors the grid +- and if it detects export it charges, if it detects import it discharges.

  • Registered Users Posts: 2,174 ✭✭✭ cute geoge

    Just reading up on renewables here for the past few months here just trying to find my feet .hypothetially speaking if I purchased a 5kwh battery for use during day and peak times but if this battery was charged at e.v. rate (i.e. rate 2-5 am 5 cent unit) could it make it feasable for payback .

    Presuming the battery cost and setting up E3k how long should it be to payback.Back of fag box calculations Would a charged 5kwh battery supply 5 units at day/peak prices so here goes 365 days x5 units x saving by charging at ev rates = 20 cent saving would come to 365 euro so it would take 9 years for payback at current electric prices .

    Another question is how long would it take a 5 kwh battery to charge would it charge fully in 3 hours

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  • Registered Users Posts: 2,498 ✭✭✭ yankinlk

    My 5kw battery can charge in an hour off the grid, but I prefer to charge it at a much slower rate... but I don't have an EV 3 hour rate on my contract.... yet

  • Registered Users Posts: 1,316 ✭✭✭ Manion

    Do read the fair usage policy with those contracts. I was looking at one and it was limited to 70 units a month, so one full charge or a modern EV.

  • Registered Users Posts: 1,268 ✭✭✭ JCJCJC

    Is there any word at all on any of the electricity companies allowing an export tariff for micro-generators? I have a 14Kw panel array, no battery and I’m giving a fair bit away to Electric Ireland for nothing. I’m happy with the panels but would love to get some credit for what my system exports. I would have thought that with all the guff about offsetting carbon, and making homes more efficient etc that a scheme would be in place by now.

  • Registered Users Posts: 13,425 ✭✭✭✭ AckwelFoley

    Nothing clear about domestic rates yet

  • Registered Users Posts: 1,268 ✭✭✭ JCJCJC

    Looks like something is coming in the current year though, doesn’t it? However, mine is over the 6 Kw limit.

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  • Registered Users Posts: 13,425 ✭✭✭✭ AckwelFoley

    That was on Denis Naughtons LinkedIn so I'm expecting its accurate

    As I've said before. The ESB aren't going to lose out. Someone is going to have to pay for those in incredible wages and pensions they're on

  • Registered Users Posts: 41 peterwhit

    Was thinking the same myself. Silly question: what’s the E3k?

  • Registered Users Posts: 2,174 ✭✭✭ cute geoge

    I put battery cost installed at 3000 euro (E3k no euro symbol in my gadget),Would not have a clue really of cost of 5 kwh battery so just educated guess

  • Registered Users Posts: 3 euonymous

    Wonder if I can join in here? I'm looking for advice on what would be a sensible route to take for a house with fairly low electricity usage currently, about 26oo kWh per annum. WFH and no electrical vehicle at present, though probably will acquire one in maybe 4-5 years. Fairly low hot water usage so not thinking of a diverter to heat water. People seem to be suggesting that it's better to go for more panels to start with--any suggestions as to what would make sense in this case?

  • Registered Users Posts: 1,476 ✭✭✭ MAULBROOK

    My only advice is fill the roof with panels, you can never have too many. It doesn't matter what is your usage is now as your usage will go up over time.

  • Registered Users Posts: 3 euonymous

    What kind of guarantee should you expect on both the components themselves and on the installation? And are there some brands of panels, inverters, and batteries that are recommended and/or worth avoiding?

  • Registered Users Posts: 1,476 ✭✭✭ MAULBROOK

    You should be looking at 10 years for the inverter and battery. 25 years manufacturer warranty for the panels. 5 year warranty on the installation.

    Solis The most common inverter from what I can see has been very robust and reliable. Its not the smartest but dose the job.

    Batteries like Puredrive, Pylontech and BYD again are very popular. Installed widely.

    Panels, anything less than 340watt should be dismissed imo as they would be of the cheap and cheerful variety. Anything above 370watt should be your target.

    If anyone else wants to chip in please feel free. These are just my observations from and personal experience.

  • Registered Users Posts: 1,268 ✭✭✭ reboot

    Agreed with looking at half price mains electricity,economy 7,its just gone up to 12 p / unit,kilowatt hr..

    As far as charging an EV,I understand that my model will only accept a charge starting at 10 Amps upward..That's quite a PV issue installation, and at what cost?

  • Registered Users Posts: 531 ✭✭✭ jethrothe2nd

    I have similar usage to you - even slightly lower, although I would expect it to go up over time. I have 10 x 380kwh panels which is the most I could fit on my roof, along with a Solis inverter and an Eddi diverter. I only had it installed late last year so I am still finding my feet and trying to optimise everything to get the best out of it. I'm withholding judgement on whether I wasted my money getting the diverter but it was definitely the right thing to do to get as many panels as possible up there.

  • Registered Users Posts: 2,498 ✭✭✭ yankinlk

    Different folks will have different priorities based on their own needs - but Im going to rerank your list based on my thoughts:

    #1 * Monitoring of solar power generation and battery usage Default! Any system should provide this included ideally with an APP - unless you go DIY maybe.

    #2 * Being able to use Solar for EV charging Personally I dont have an EV - but If i did I would want the flexibility to be able to do this! It may not be all that important unless your EV is parked at home in the sunshine tho.

    # 3 * Being able to charge a batter on Solar or Night rate I think this is very important and is a deciding factor in wether or not to buy a battery (and what size that battery should be.). Buy a battery (or build a DIY battery) if you think you will have a need for electricty AFTER the sun sets. In winter its a good strategy to charge the battery at night to use during the day when solar production is low. If you choose NOT to install a battery its not the end of the world - maybe your needs are low.

    # 4 (optional) * Being able to heat water with excess power This is optional - and different people will rank this differently. Use a LOT of hot water then this might be more important. But for the average person this is more about conveinence of having hot water on demand and a "good feeling" of using green evergy to heat water. However it may cost more money than it saves to implement.

    # 11 * Being able sell excess power back to the grid This should NOT be a consideration for the average person. Its not likely that WHEN the residential FIT/CEP tariff comes in - will anyone "make money" doing this. Self consumption is the way to go for 99% of us.

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  • Registered Users Posts: 3 euonymous

    a couple of questions. Are there different ways of collecting information about what your solar panels are generating and how you are using it? If it's via an app, presumably that means that the system is linked up to your internet router or maybe your phone, and does that mean another SIM card? Can you get a record of what is happening that you can look at in a spreadsheet etc and if so is there some specific software that needs to be installed with the system?

    Also: on charging the battery on the night rate: doesn't this defeat the purpose somehow? also, if you have a smart meter, can you get a day and night rate?

  • Moderators, Social & Fun Moderators Posts: 12,804 Mod ✭✭✭✭ AndyBoBandy

    Regarding the monitoring;

    My Installer installed a WiFi dongle that simply plugs into the inverter and then connects to your home network. The app(s) then connect to your inverter through their cloud services so you can always see what the system is doing. I dont think it shows live data, but rather a snapshot taken every 5 minutes of what the system is doing. You don’t need to be on your home network to see this data either, I.e. out and about.

    heres what my system is doing right now via the SolisCloud app;

  • Registered Users Posts: 2,498 ✭✭✭ yankinlk

    @euonymous "Also: on charging the battery on the night rate: doesn't this defeat the purpose somehow?"

    If saving money isnt a goal maybe? :) Fair question, it depends. Lets say you only use 10KW of units per day. And you are blessed with a location that has sun ALL day - maybe you get 10KW most days minimum! Then build a small tidy system wihtout a battery. As long as you are AT HOME when the sun is being generated - then you can use it INSTEAD of pulling from power grid without a battery.

    If however you are not home and using power when the sun is making it - you need somewhere to store it - the size of battery should probably match the amount you need to consume (or a ratio of it). I need 20-30KW per day for example and i opted for the larger 5Kw battery... its still not enough for my needs - but to add another is very expensive...

    " also, if you have a smart meter, can you get a day and night rate?"

    Im no Smart Meter expert - in fact I dont see any advatage to getting one. I has a Day/nigth meter put in in order to take advatnage of cheaper night rates. BUT I think that there is a Night rate option for Smart Meters - its just that at the moment ALL Smart Meter tariffs have higher Day and Night Rate prices...

  • Registered Users Posts: 3,456 ✭✭✭ TaurenDruid

    and often find myself turning on the washing machine or dishwasher to prevent feeding unused production up to the grid.

    Is this not the opposite of sustainability - needless consumption rather than feeding clean energy into the grid?

  • Moderators, Social & Fun Moderators Posts: 12,804 Mod ✭✭✭✭ AndyBoBandy

    The clothes need to be washed anyway, and normally I'd do this on the night rate as it's cheaper. Also at night the ratio of green vs fossil electricity is higher so theres a greater chance you are using more greener produced electricity. It's not like I'm washing already clean clothes because 'why not it's free'!!

    If I do that same wash during the previous day while I'm generating plenty of electricity from the sun, is that not even better again? Means I won't be taking that 1kWh or so from the grid at all later that night, regardless of where it's coming from.

    If I've no clothes or dishes to wash, and I'm about to start exporting, I'll plug in the car and set it to charge at 1kW for an hour or so..

    I paid (a lot) for it, so I want to use all of what I produce, or certainly as much as I can. Then whatever's left can go upstream..

  • Registered Users Posts: 2,498 ✭✭✭ yankinlk

    the opposite of sustainability would be to be so mean as to turn on your electric lawn mower and let it idle in the driveway just to avoid sharing an extra leccy.

  • Registered Users Posts: 88 ✭✭ Fantana2

    If money was no object, what would be the max kw of panels to put on a southerly roof?

  • Moderators, Social & Fun Moderators Posts: 12,804 Mod ✭✭✭✭ AndyBoBandy

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  • Registered Users Posts: 1,476 ✭✭✭ MAULBROOK

    Ideal for me, 8kw about 24/26 panels.

    6kw Inverter, 10kw plus of battery.

    In other words, fill the roof