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New solar install without battery?

  • 02-02-2023 11:43pm
    Registered Users Posts: 9

    Hey All

    Thinking of a new solar install on a south facing roof. Probably get 16 to 18 panels on there giving me 6.5 to 7 KwP. South facing roof.

    Was going to skip the battery and go with an Eddi and FIT. Have a Zappi installed also for when EV arrives sometime this year.

    Will the FIT pay me / give me credit and I buy back the electricity when I need it hence making the battery uneconomical?

    Going by the calculator on here I'd be at about 9k outlay after grant. I could spec a hybrid inverter that will allow me to build out a battery array down the line.

    Would this be the way to go?


  • Registered Users Posts: 1,405 ✭✭✭DC999

    I have no battery and an EV and that works well for me. EV charges from panels a lot of the year. But EV needs to be in the driveway a lot of time during sunlight

  • Registered Users Posts: 2,225 ✭✭✭SD_DRACULA

    Depends on what tariff you're on.

    If you get FIT for 18c and each grid unit costs you 40c+ then the grid is not your battery (or your friend)

    But also if the installer is peddling you a 5kwh battery for 3.5k don't go for it, only makes sense if you get it around 1.5k but best value is always in DIY battery.

  • Registered Users Posts: 1,405 ✭✭✭DC999

    Very true! Let me rephrase my last comment. To get the best efficiency out of the solar, I’d have a battery. We could gain more savings with a battery, but not until we paid off the loan. I do believe we’re in an era of high energy prices, not trying to scare monger – just IMHO. So a battery would help that for sure (without a battery you pay the gap between FIT and cost for a day rate unit when need to buy it back)

    But getting solar without a battery has still helped our energy bills hugely. If it comes down to not getting solar because you can’t afford a battery, get just solar. Can always revisit the battery in the future.

  • Registered Users Posts: 21,345 ✭✭✭✭ELM327

    Excuse the crude analogy Getting solar without a battery is like having sex using condoms. It's kindof related to the real thing but not really.

  • Registered Users Posts: 119 ✭✭Sikie

    Solar without the battery is a sub-optimal solution, over the last 19 days since switching to an EI night boost plan I can say the following with a PHEV charged every night the baseline usage would be 719 kWh on the old plan with a 22% discount to normal rates this would be €238.87, with a solar generation of 108kWh from an 8.2kWp system SSE facing this provides a savings of 17.65% however with 7.2KWh of battery and the EI night boost plan I have effectively altered my demand to get another 30.3% of saving by prioritizing the night boost slot and the night rate and having enough between storage and solar to cover as much of the day/evening demand as possible. There is scope to save more by having enough battery to always cover the day/evening demand from either solar or the previous night in my case I believe there is another 28.8% of saving to be obtained by adding more battery capacity, this would pay for the extra batteries in about 4 years

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  • Registered Users Posts: 182 ✭✭Fantana2

    Has anyone done the maths on spending 9k on a solar system basis a standard inverter and more panels Vs hybrid and a battery?

    Would the increase in generation and extra fit in the summer be enough to bridge to cover the extra day units by not having a battery.

    Theres also an argument it’s easier to add a battery diy later than get up on the roof for more panels.

    The above is assuming of course you have space for more panels.

    6.96kwp South facing

  • Registered Users Posts: 1,991 ✭✭✭jkforde

    or you could just lash as many as you can on the roof, install a hybrid inverter in case you decide on battery later, and you can always just swap it out (and sell the hybrid) for a non-hybrid unit later if FIT\CEG stays fairly priced (abs no guarantee of that esp. with the current state of the CRU!). also, the economics of dedicated HW diverters is questionable esp. with the rise of smart switches and home automation etc. best of luck on your solar journey, it's worth it!

    🌦️ 6.7kwp, 45°, SSW, mid-Galway 🌦️

  • Registered Users Posts: 2,730 ✭✭✭yankinlk

    The math is very much done uniquely for each house, based on many factors.

    No battery means you require more time in the home managing self usage of the LIVE generation. Turning stuff on with timers on remotely works too... Aim for peak times of the day like 1130 to 230... But that depends on your aspect of panels as well.

    Choices around using an Eddi or having an EV in the driveway can be used instead of a battery... It really depends on just too many factors to have a simple formula to suit all.

    Go for it without a battery for a year...then assess how you can improve... With a change of habits or system design.

  • Registered Users Posts: 8,444 ✭✭✭micks_address

    yeah its an interesting one for sure. I guess with export you are capped at 200 euro tax free generation.. re an eddi.. i have one and im torn some days on whether i should use it or let the surplus export.. i can probably get marginally more for export but the convenience is handy.. also have an ev and solar charging is great but slow.. ill be able to comment more in the summer as i only have my system since november. if i was starting again and had to choose between a battery and solar id nearly get a battery first with hybrid invertor.. add the panels later.. the battery can save you a lot all the time even when the sun aint shining.. import cheap and avoid day rates.. whereas the solar only helps in brighter days. As you have a south facing roof you will be able to maximise generation so plaster it with panels whenever you go at it.

  • Registered Users Posts: 1,405 ✭✭✭DC999

    I was thinking similar for my folks who couldn’t afford both. But if it comes down to one or the other, solar is better IMO. Good Q to ponder though.

    Solar is 20+ years. You’re getting free juice from day1. And only buying the 'gap' not available from solar. It’s a ‘set and forget’ no maintenance costs or management.

    With batteries, you’re forever buying up to 120% of your energy. 100% of energy (assuming the battery runs everything which is a stretch of course) plus have up to 20% losses on that (for in and out of battery). And the savings only works if there is a cheap night rate that let’s the batteries fill. Existing 2 or 3 hour smart meter EV tariff wouldn’t cut that, or just about depending on battery size and rate it can charge. Would need the D/N meters to stay and the decent night rate on those. That’s questionable with the smart meter rollout. Plus batteries will deteriorate and lose capacity all the time – just a fact of the chemistry. Our EV is the same.

    You’re only live since Winter afaik so haven’t seen spring + summer output. So you’re battery is saving you a lot in Winter – but that will start to reduce in a few weeks when we get more sun. I’m only live since end July. Summer output is unrealllllll. You’ll produce more than you can use unless you’ve a large battery. Then get paid FIT on what’s ‘sold’ back (ok, FIT rate may well drop in time so people can factor that in). 

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  • Registered Users Posts: 8,444 ✭✭✭micks_address

    i think if you are home a lot then solar is definitely a way to go instead of a battery if its either or.. you can put on washes etc and use the energy and sell back what you dont use.. the fit is decent at 21 cents (with ei).. having to shell out 5k to replace my battery in 10 years isnt a comforting prospect.. only live since november so you are right.. i need to see a full 12 months..

  • Registered Users Posts: 2,730 ✭✭✭yankinlk

    A battery in 10 years will be very different tech and price. I would expect more capacity for less money.

  • Moderators, Home & Garden Moderators Posts: 5,773 Mod ✭✭✭✭graememk

    I'd say it will be more capacity for the slightly more.. inflation... Base cost of manufacture, etc hard drives for instance

    But €/kwh should be less than it is now.

  • Registered Users Posts: 2,730 ✭✭✭yankinlk

  • Registered Users Posts: 1,405 ✭✭✭DC999

    :) Capacity is deffo climbing. Leaf used to be 24kWh when first shipped in 2010 ish. That was huge at the time. Now 60kWh+ available. VW have 80kWh+

    People here have larger home batteries than our 6 yr old Leaf :)

  • Registered Users Posts: 64,745 ✭✭✭✭unkel

    Even just 2 years ago the very few people that got a battery (grant) install in Ireland typically had a single Pylontech (2.4kWh) home battery. I went up to 45kWh yesterday 😂

    Also have over 100kWh in my cars, all accessible, but not easy. And only if they are there and hooked up - to custom DIY made systems. This is the main area of improvement over the next few years - we are all waiting for reasonably priced V2G solutions that can benefit most or all EV owners. The holy grail!

  • Registered Users Posts: 4 uponontheroof

    Hello , what is a fit ?

  • Registered Users Posts: 5,763 ✭✭✭con747

    It is the Feed In Tariff (FIT) you get paid for exporting excess electricity back to the grid. Unless your winding us up 😂

    Don't expect anything from life, just be grateful to be alive.

  • Registered Users Posts: 4 uponontheroof

    Hi , I have been in talks with two solar companies. I got very similar quotes from both . One company is offering a solis inverter and the other has offered a sungrow invertor.

    The people offering the sungro said its in a whole different league.

    When doing some searching on Google both see fairly good . Coukd anyone here advise which should be better . Thanks in advance.