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Eddi or Alternative??

  • 28-01-2023 2:11am
    Registered Users Posts: 165 ✭✭ bootser

    Hi All

    PV install due mid Feb, 12panel 4.8Kwp. Intending to self install an immersion diverter and had a couple of questions for the more knowledgeable out there!

    1.I currently have a smart switch on the immersion and Ill be getting a 5Kw Solis inverter with my set-up, could I just use IFTTT to trigger the immersion on if excess solar was detected from the array? or is this unworkable/bad idea?

    2.I have sourced an Eddi+Harvi for approx. €520, but the same company have an alternative solar diverter for €330 but it doesn't support remote operation. Is the Eddi worth the extra €200? Linky:

    3.If I go for the Eddi, Ill be using the Harvi to monitor the mains at the ESB meter, is there any need for a second CT anywhere else e.g. on the AC at the inverter to monitor solar generation, if so does that need a second Harvi?



  • Registered Users Posts: 1,179 ✭✭✭ Galego

    I'll have the question with my knowledge on this.

    1- Yes it is doable through HomeAssistant but not convinced it'll work as well and efficient as a proper diverter. I may be wrong on that statement though.

    2- IMO, i'd pay the extra money for a brand which I am familiar with and have excellent customer service support. I've contacted them few times and they are brilliant. Well worth paying extra for.

    3- You dont need a second harvi. The solis monitors your PV generation. Do you mean you'd like to see it in the MyEnnergi App? If so, you can clamp a CT in the live cable coming from the inverter.

  • Registered Users Posts: 1,292 ✭✭✭ Big Lar

    I have a shelly one plus PM controlled by HA and it seems to be working fine.

    €20 for the shelly vs €520 for the Eddie is a no brainer.

  • Registered Users Posts: 1,255 ✭✭✭ Nelbert

    Thats all or nothing though. You can't control how much the immersion heater gets. Eddi provides the granularity to put 1kw in if that's your excess.

    If you've a 3kw heater you're on the upper limit of the Shelly's amp rating too.

  • Moderators, Sports Moderators Posts: 17,446 Mod ✭✭✭✭ slave1

    EDDI is very user friendly too via the App, touchscreen control to turn of/off, schedule heating times, immediate heating button etc

  • Registered Users Posts: 3,580 ✭✭✭ graememk

    If going for the eddi over the iboost, id be saying go for the eddi, The Iboost is fairly loud, vs the eddi being silent. (ah,, Its not an Iboost... I'm not sure then!)

    If you had batteries, id say stick with the smart immersion, but Inverter only, Id be going for the eddi,

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  • Registered Users Posts: 1,292 ✭✭✭ Big Lar

    Amp rating for Shelly is 16A, immersion draws about 12A. 2.8Kw so plenty of overhead.

    As for the control, if the conditions are over 88% battery and over 1800w from solar panels then turn on immersion for 20mins and then check again. So the battery takes any slack.

  • Registered Users Posts: 119 ✭✭ Sikie

    I would question the benefit of an Eddi, my logic is that with a smart meter, you could use one of the night plans to heat the Hot water at night with a simple time switch, e.g. Electric Ireland 2am-4am @ €0.1228/kWh ex Vat, Energia 2am-6am €0.1288/kWh ex VAT or SSE 2am-5am €0.1139kWh ex VAT and take the export value of the solar kWh that are generated and credited at €0.21, €0.18 and €0.24 respectively instead of heating water with them.

  • Moderators, Sports Moderators Posts: 17,446 Mod ✭✭✭✭ slave1

    That's fine except when morning showers empty the hot tank and you need day rate to heat back up again

  • Registered Users Posts: 119 ✭✭ Sikie

    Fair point however if you needed to reheat the hot water tank during the day you could switch on the immersion via the time switch for a 1-2 hour window depending on your needs around the peak of the solar production curve during the day thus creating the best chance of catching solar kWhs if they are there.

  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 61,224 CMod ✭✭✭✭ unkel

    Good points, but a lot of us are still on day / night meters with no sign of any smart meter, could be several years away. And we get a deemed export, so not being paid for our actual export. I just fitted an eddi and it could very well have fully paid for itself before I get a smart meter. Note: I do have a very large 11kwp PV setup and we do use lots of hot water

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  • Registered Users Posts: 1,089 ✭✭✭ snowcat

    I am installing a PV system too and struggling to see the advantage of an Eddi at 600 euro. A well insulating new tank should lose very little water heat through the day. Would it not be better to heat at night and leave the solar do its thing during the day. I presume the electric power from the PV will feed the immersion without an Eddi? It would be in the summer that this is most important as the CH will heat the water in the winter.

  • Registered Users Posts: 1,255 ✭✭✭ Nelbert

    I think that's the point an Eddi mitigates the need to use any paid for energy for water for about half the year and provides the flexibility to adjust to your generation / export level.

    You can do it with Shelly's etc but without the auto adjustment based on how much you are generating.

    They are expensive for what they are but integrate well with HA and provide enhanced functionality vs simpler approaches (which are still valid as long as you know the limitations).

    Heavy HA user myself (all lights, heating, motion etc) with multiple Shellys installed and I'd still lean towards getting an Eddi in a "right tool for the job" sort of line of thinking. But others will think the price exceeds the value.

  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 61,224 CMod ✭✭✭✭ unkel

    Price depends of course on how much you pay. New they are €632 incl. VAT from

    But if you get trade discount and don't pay VAT, it's only a bit over half that price 😂 With of course the second hand value higher than that even after using it a year or two. So basically it doesn't cost anything.

  • Registered Users Posts: 1,749 ✭✭✭ jkforde

    sure, but if the HW is drained in the morning, you'd have to turn on the immersion boost (not variable afaik, so max immersion rating import - any solar surplus)... but imo what's neat is that the Eddi is able to trickle a low amount (down to 100w?) of surplus during the day which is great on cloudy winter days (of which there are maaany over Wesht!) and as a bonus slowly heats the water and reduces some of the tank stratification (can also limit the Eddi to a specific max load which is great).

    ok, same functionality is all achievable for way less money down the DIY road...

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

  • Moderators, Sports Moderators Posts: 17,446 Mod ✭✭✭✭ slave1

    What do you mean by "can also limit the Eddi to a specific max load which is great"?

  • Registered Users Posts: 1,749 ✭✭✭ jkforde

    @slave1 I mean Eddi Supply Grid – Device Limit, or am I misunderstanding what it does?

    Post edited by jkforde on

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

  • Registered Users Posts: 770 ✭✭✭ DC999

    'Sets the maximum current that the eddi will draw (including when boosting). This is useful if the supply current is limited, like a 13A fused spur rather than a 16A MCB.' - Zappi is the same, can limit itself. But it limits it all the time. Could be useful if there is a short cheap-rate time window and have a lot of other devices pulling a heavy load.

  • Moderators, Sports Moderators Posts: 17,446 Mod ✭✭✭✭ slave1

    Ah, understood, AFAIR all immersions in Ireland are hard wired to the consumer unit and max at 3kW, I can't see any need to restrict an EDDI, sure it's the same as a kettle/mini oven etc.

    If someone is running their immersion off a 3-pin socket then that's a separate issue onto itself