EDDI & Battery- Worth it?

I'm getting quotes for solar, and have identified the company I'm likely going to use. They're offering options to include an EDDI for hot water (around €500) and a 5kwh battery (about €2,500). The array will be about 6kw E-W.

Is it worth going for one or both of the EDDI and battery? At what price point would it be worth it? And what other factors are worth considering?

I'd particularly appreciate views from people who regret getting or not getting them in their installs on why they have regrets!

Thanks.

jkforde

https://www.boards.ie/discussion/comment/121967556#Comment_121967556

read back through the quotes thread, you'll get a gist from various folk

I looked there first, and in the last couple of pages one person said- without explanation- they wouldn't get a battery again. There may be more specific answers elsewhere in that thread, but if trawling through the internet answered my question I probably wouldn't have bothered opening the thread.

Also, I'm not looking for the gist I'm looking for opinions on a specific question based on experience. There's a difference.

lau1247

Eddi was very useful back when there was no FIT so people would try to use up as much of the energy produced as possible since they are not getting paid. Now that FIT is available, it doesn't make sense. Especially when Gas would probably be more efficient. As for battery, it depends on your usage whether 5kwh is sufficient or not. The usefulness of battery would be to buy cheaply from very low night rate, use none during the day (Sell excess to grid - i.e. buy low sell high) and/or top up by solar during the day if you predict it to run out before night rate comes around. That's the gist of it. Drop the Eddi.

loyatemu

I got roughly the same system and went for the battery but not the Eddi.

My reasoning for not getting the Eddi - I can heat water with gas for 9c a unit and sell electricity back to the grid for 19c. Even if the export price decreases, I'll probably end up on a smart plan with cheap night rate electricity so can heat water on a timer for cheap. I've also heard some stories of them being unreliable.

As for the battery; I like the idea of using as much of the solar electricity myself, even if the economics of a battery don't totally stack up at the moment. The economics may change though, the current export rates are probably as good as they'll ever be and will decrease over time. It also gives the option of charging up on cheap night-rate electricity in the winter (though I only got a 5kW battery so it won't make a huge dent in my winter usage).

So flexibility basically. If you're strictly looking at payback time, the battery doesn't make sense, but payback is going to be changeable with electricity import and export rates constantly changing.

allinthehead

https://www.boards.ie/discussion/comment/121968930#Comment_121968930

It's a difficult question to answer. The Eddi will struggle to pay for itself at the moment as you get paid for the export, so if you have a low night rate for electricity then better to heat the water at night. Fyi, I installed an Eddi as I want to stop using gas for heating the water and I'm maxed out at night in my cheap rate window. I think it's a great bit of kit, I also have a Zappi and they work well together.

The battery is a difficult one to answer too. Just to note first of all that most batteries can only go as low as 20% state of charge, so your 5kwh battery may only give you 4kwh. If you have a peak day rate, the battery will help keep you off that and it's good for the national grid too. Ask if the installer will do a deal on another 5kwh battery to bring the cost per kwh down a bit. At install is the cheapest time to get them as they're vat free and installer already on site.

Depending on your ability or the ability of people you know then Diy battery might be of interest. There's a thread here for that.

Another thing to remember is that all this is in a state of flux and what people advised 2 years ago is no longer relevant. CEG has changed the game and flexible tarriffs coming down the line will change it again.

Macker

Get a hybrid inverter so you can add a battery later if you want ,I got an eddi because it made sense at the time i wouldnt now, I recently added a second 5kw battery and since then I'm going to bed with about 70% charge left so I'm going to export for an hour at night before charging again at cheap rate.

_Puma_

Hybrid Inverter + FIT + Battery

No Eddi needed.

With a standard inverter, no battery and/or no FIT the eddi is a fantastic addition.

I do like the myenergi app for real time monitoring with the CT clamps. I'm sure with the more recent hybrids you can get this too.

slave1

Depends, we have 6 in the house for a while, even with a 300l tank some long showers drained the hot water today, now I have excess diverting from export to heat the water for anticipated evening showers.

€500 for an EDDI fitted is a very good price.

Also, FIT is artificially high at the minute, if it drops to wholesale prices then EDDI will be back on the playlist.

Battery only worth it if you can DIY it

Thanks for all the feedback. I'll skip the eddi and battery- I'm all about the payback on my investment.

_Puma_

Another "smarts" the eddi has is the dual output supply.

For larger tanks with dual immersions will lead to less stratification in the tank.