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21-02-2019, 14:38   #1
unkel
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Home attached battery storage solution

Looking to install a battery home storage solution in the next few months to work with my 3.8kwp solar PV install. I already have a solar thermal hot water heating system and the family car is an EV

I've decided on an AC coupled system. I'm thinking of this AC inverter:

SoFar ME 3000SP

datasheet

It's basically an AC coupled inverter that you attach a 48V battery to. The inverter will sense if you produce more PV than you use in the house and will store the difference in the battery. And if you use more electricity in the house than you produce, it will use electricity from the battery instead of from the grid

Both ways to a max of 3kW

As a battery you could go the neater but more expensive li-ion route with say a Pylontech 2.4kWh battery. Both together here for sale for GBP1299 + VAT

Linky

Or you could just pick up the inverter for about EUR700 and then some used lead acid deep cycle leasure batteries second hand cheaply

If you get this work done by an SEAI installer, you are entitled to €1000 subsidy. Or you could DIY with the help of a friendly electrician (and not get the subsidy)

Any of you planning to do this? Any tips / opinions? If there are any SEAI installers here, you can PM me with a quote!
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21-02-2019, 15:02   #2
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And maybe I should have stated the obvious: I would like this done as cheaply as possible. The aim is to have a pay back period as short as can be done, while future proofing the system. I could easily replace the lead acid batteries with a 10kWh li-ion pack in a few years time when they come down in prices. I reckon if I do a DIY install with say 4 * 120Ah lead acid batteries (giving about 6kWh of which maybe 4kWh is usable) for not much more than a grand in parts

If I could then self use say 60% of my annual PV generation of 3800kWh, instead of maybe just 20%* without a battery (is this a reasonable assumption?), I would save 3800 * 40% * 18c = €275 per year, or a pay back time of around 4 years.

*this 20% is a very low figure. It implies that 80% of my solar production is going back to the grid for free. I do feel it is going to be quite realistic though, unless you spend your life switching on appliances during the day while the sun is out, pluggin in your car to charge during the day, etc.
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21-02-2019, 18:16   #3
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Interested.

Does the current invertor need to be a specific spec to allow battery storage?
I know I have a trannergy invertor.
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21-02-2019, 19:13   #4
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If you have solar PV already you have 2 options:

-change your solar inverter for a hybrid solar inverter. These are not cheap though. You're talking about €1200 + VAT for one retail You recoup some money by selling your old one. But you're not the only one with this plan and simple inverters can be picked up cheaply now. The batteries attach directly to the hybrid inverter. I call this a DC side install. Benefits: less hardware, simpler install

-keep your inverter. But then you will need a battery inverter like the SoFar I linked to above. The batteries attach directly to the battery inverter. I call this an AC side install. Benefits: cheaper, more versatile and you can charge your batteries with night rate (as well as solar), this AC side works completely independently of your solar system
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21-02-2019, 19:37   #5
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Unkel, your assumed self-consumption is reasonable, assuming your heating system is not electric. (Mine is an air-to-water, and I'm at 67% self-consumption over the last 12 months, using my 5.2kWp array in Dublin...we also have an electric range oven, and UFH, as our 'batteries'...we even charge our EV using a Zappi/solar surplus...still the prospect of a battery to soak up the remainder is very tempting...).

Thanks for the link. The SoFar batteries are surprisingly cheap, very much cheaper than quotes I've had for Sonnen products.

Let us know if you have any interesting SEAI-installer contacts!

Roll on the day when we can V2H our cars! Mine is CCS and there seems to be little prospect within its lifetime of using it as our battery.
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21-02-2019, 19:52   #6
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Welcome to boards.ie Coltrane, nice first post!

V2H is still years away from being affordable unless you have a CHAdeMO EV and your utility provider is installing all the hardware for free as part of at trial My own car is CCS too. I thought of replacing my dumb EVSE with a smart one, like a Zappi, but they are very expensive for what they are and of limited use, even if your car is usually parked at home during the better solar hours.

My house is old skool, so I have gas heating and gas hot water (well mostly solar), no electric heating and no electric showers. Electricity use is about 3.5MWh / year for normal household use excluding EV

As for costs, it does matter. You can install everything Sonnen and Tesla and it will look good, but the payback time will be longer than the life of the hardware. Those systems cost you money, not save you money. That doesn't work for me. Saving the planet shouldn't have to cost the world
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21-02-2019, 21:25   #7
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Another possibility for you, Unkel, could be to invest in an electric space heater. These can be set to switch on only with surplus solar. Good for bright but chilly days. I use a far infra-red 400w free standing unit in the kitchen with a Smappee smart plug. Fairly low cost and probably less depreciative than any newish battery.( But you’re thinking of old lead acids!)

You could of course go the whole hog and buy a heat pump - that’d soak up your solar surplus!
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21-02-2019, 21:47   #8
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I already have two large electric space heaters - crypto mining rigs and they'll be running for another few months usefully (heating up the house) and basically as long as I don't have a battery solution in place. I should be running these from 10AM until 5PM and then on night rate from 11PM until 8AM (so I don't run them fully on full day rate electricity from the grid), but I'm not bothered with that.

Smart cheap electric space heaters, that's interesting. Does the Smappee smart plug work directly with a CT clamp or what way is that setup using solar surplus?

I know nothing about heat pumps, but my house was built in 2000 and has very poor air tightness, I don't think it would be suitable. Also my gas boiler is an excellent 98% efficient Viessman and was only installed 6 years ago. Leaving that well alone.

Space heating with excess electricity is only useful in winter though and in summer I make the most electricity...
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21-02-2019, 21:49   #9
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Keep your hard earned cash in your pocket and buy something nice to your wife ,guys !
Batteries are not for us,normal home owners,green willies saving the planet.
Not today...

Surplus for a good PV system ... i wanna see that being used for a heat pump or space heater when needed in the winter.
Your system barely warms up the bumble bees looking for something warm to their cold arse...or plan to use the surplus of PV in the summer for what !??

Good luck and do please share here your adventure....i'll do mine in couple of years,no offence.


Attached Images
File Type: jpg 20190215_124755.jpg (140.1 KB, 1407 views)
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21-02-2019, 22:06   #10
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Quote:
Originally Posted by rolion View Post
Keep your hard earned cash in your pocket and buy something nice to your wife ,guys !
Says the man who bought a EUR1500 ABB inverter

My Solis 3.6kW dual MPPT inverter set me back GBP220 brand new including shipping. And I have made a profit selling on all my previous solar equipment for more than I got it for

Picking up a few EUR50 deep cycle 100Ah leisure batteries tomorrow to have a play with. Four of these would give me a 5kWh battery for EUR200 (plus cost of cabling / clamps)
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21-02-2019, 22:16   #11
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@unkel

Do you have access to my fcuking bank account that you know how much i fcuking paid for it !!!??
Second,when i bought my ABB years ago,you didnt even knew about PVs ...AND ... ABB was the only one inverter certified by ESB to work on their grid. I am more than happy with the system,best in class, industrial graded equipment,it did 9MWh,9,000KWh,9.000.000 units since day one.

So please back off with your silly, childish accusations.Dont getting me fcuking started...please...

I'm in for longer,i am waiting for others to buy expensive "ABBs" so that i can use that shared expeience and get a proper one...
My LEAF is "saving" every drop of their cells, waiting to come in the house...my eNV200 40KW once is writen down as business expense,same coming up in the house. that's almost 60KW and few hundreds of Ahsss...

Be good and take care,enjoy the PVs and EUR50 DC batteries ...buying ,selling and trade-up on other's pockets

PS

Found another picture of warming the invertor,the ABB one ... even bees loves it !
Dedicated for you...

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File Type: jpg ForUnkel_Good winterTimes_warmAsses.jpg (119.8 KB, 1374 views)

Last edited by rolion; 21-02-2019 at 22:22.
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21-02-2019, 22:29   #12
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Unkel, yes Smappee measures consumption and production using CT clamps. Its control box can send programmable on/off signals to the smart plugs (max 3kW load, too small for your rigs), so for example I’ve mine set to turn on my 400w heater when there’s a 450w or greater surplus and back off again as soon as the surplus disappears.
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21-02-2019, 23:00   #13
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My rigs are a touch over 1kW each, so not as big as you thought. And I could scale them down from 2 to 3 smaller rigs or even take out a few GPUs and sell them on. Don't want to switch the rigs on / off all the time though, it takes a good few minutes for them to boot up, connect to a mining pool, load the DAG files for each GPU, start mining and spool up to the max hash rates.

Any link to where you bought your Smappee system? Interesing stuff all the same!
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21-02-2019, 23:20   #14
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@unkel
you want some FREE of CHARGE batteries !?
See attached...just broke them down today from a 1,500VA ups.
PDF data specs atatched too.
save the eur50 !









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File Type: jpg 20190221_144820.jpg (211.4 KB, 896 views)
File Type: jpg 20190221_144802.jpg (221.9 KB, 895 views)
File Type: jpg 20190221_145110.jpg (252.2 KB, 880 views)
File Type: jpg 20190221_144800.jpg (304.5 KB, 884 views)
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File Type: pdf dow01520317501.pdf (509.3 KB, 1090 views)
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21-02-2019, 23:58   #15
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They seem to be 6V, 7Ah. So You'd need 125 of them for a 5kWh setup, would cost you a grand in cabling alone and a good few days to hook them all up. Or am I missing something here?

Thanks for your kind offer anyway
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