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  • FIRST POST
    • Martyn1981
    • By Martyn1981 5th Dec 16, 2:57 PM
    • 8,685Posts
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    Martyn1981
    On-grid domestic battery storage
    • #1
    • 5th Dec 16, 2:57 PM
    On-grid domestic battery storage 5th Dec 16 at 2:57 PM
    Hello!

    Right, as discussed elsewhere, battery storage for self generation (typically PV) is interesting (to some), and gathering momentum in the UK. So here's a thread to discuss it, and watch it develop.

    I've called it on-grid, as off-grid is so much more specialised. And domestic as commercial scale storage, or grid scale can be chatted about on the Green & Ethical energy issues thread.

    So, where are, well this article lists about 20 systems that are available or should be available soon:-

    Introducing CleanTechnica’s New Home Battery Overview Page

    Jumping straight in with personal opinions:-

    Economical - Not yet. Prices are falling fast, the range of products is expanding fast, and large numbers are being deployed in some countries, either because the price of leccy is high (Australia & Hawaii) or because subsidy schemes exist (Sweden & Germany).

    Where are we today. My needs are a 4kWh system. That's 4kWh of useable capacity, which would mean about 8kWh of lead acid (LA), or about 5kWh of lithium ion (Li-ion). My research has found batts in the high £2k and up range. I need the price to be nearer to £1.5k.

    The Tesla Powerwall II, installed is approx £6.5k, which works out at about £2.2k for 5kWh, but of course, it doesn't work quite like that, as smaller systems will cost proportionately more.

    Environmental - Tricky one this (to say the least). Until storage is needed, it's not environmental. Renewable energy (RE) generation currently displaces gas generation, which is a demand follower. Once gas generation is pushed down to zero (at times) we need storage, but we aren't there yet.

    However, to push gas generation down to zero, we need more RE, and to ensure it is viable/economic/profitable, we will need storage - chicken and egg situation.

    The advantage of storage to the environment, is to take peaks of RE and timeshift them to peaks in electricity demand. On a domestic level, this works quite well as PV generates during the day into the afternoon (or evening) depending on the month, so any stored leccy is available for the evening peak 5pm to 7pm.

    That's the background, and now here's a thread to discuss options, prices, economics, and watch things unfold. Enjoy.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
Page 50
    • Zarch
    • By Zarch 12th Jun 19, 2:03 PM
    • 274 Posts
    • 643 Thanks
    Zarch
    If you drive to work in an electric car and have solar PVs at home then you would have to work the night shift so your car can charge-up at home whilst the sun is shining. In this ideal world the battery in your electric car could also supply power to the house when the car is plugged-in at home.
    Originally posted by Reed_Richards
    You're right.

    Apologies, selfishly thinking here as it would be the wife's car ans she only works part time and makes short journeys....... so plenty of opportunity to have it charging in the day via PV.
    17 x 300W panels on a 3.68 SolarEdge system in Sunny Sheffield.
    • markin
    • By markin 12th Jun 19, 3:10 PM
    • 655 Posts
    • 553 Thanks
    markin
    Yeah I agree, its entirely about usage.

    Something like an ashp is useless to me, as the wife enjoys opening a window in every room every day.... and then putting the central heating on

    You are in the lucky position of living alone and so can dictate what will happen day to day and prioritise using most of the leccy on a bright day.

    I can plan... but the wife does what the wife does.
    It's not unusual for her to put a load in the washing machine, another in the tumble dryer, start the dishwasher and then go for a shower.

    I'm also away fairly often with work, so I need the system to be as automated as possible.

    I'm toying with the idea of the thermal store with motorised valves to isolate it with minimum temperature, but when temperature is high enough, to stop the combi boiler for hit water, this way the winter is exactly the same as now, but I'd assume my summer hot water needs would be covered.

    I just need to work out how to do it.... cheaply
    Originally posted by Solarchaser



    In a perfect world she would be fine with a heat exchanger bringing in warm fresh air, but its not, she would still open the windows
    • ASavvyBuyer
    • By ASavvyBuyer 12th Jun 19, 5:03 PM
    • 1,027 Posts
    • 3,048 Thanks
    ASavvyBuyer
    You're right.

    Apologies, selfishly thinking here as it would be the wife's car ans she only works part time and makes short journeys....... so plenty of opportunity to have it charging in the day via PV.
    Originally posted by Zarch

    Also, the EV could charge up during the night when on cheap rate electric (like Octopus Go 5p/kWh for 4 hours) and then discharge to the grid during the evening peak rate at 10p+/kWh (according to the rates published for Octopus Agile export).
    Rhondda Cynon Taf, 4kWp, W roof, 30° pitch, 16 x 8.33 Eternity 250w E+10 panels, Solar Edge SE4000-16A Inverter + P300 Optimisers. Inst Aug 2015.
    REUK Diverter, Toshiba RAS-10G2KVP-E Ultra High Efficiency Air Conditioner/Heat Pump, Kia Soul EV & 100% Green Electric Tariff.
    • markin
    • By markin 12th Jun 19, 7:19 PM
    • 655 Posts
    • 553 Thanks
    markin
    I've recently changed our TD to a heat pump model. It seems to be using a lot less energy than the previous one & the utility room isn't getting as hot which should further improve it's efficiency.
    Originally posted by 1961Nick

    I Keep reading this "Heat Pump tumble dryer" I thought people were just confused, or maybe its just me!, It seems the exact same system as a Condenser dryer to me, And that has been available for at least 15-20 years... At what point did they decide to re-brand it?


    According to the beko site It was possibly the germans 13 years ago.
    • zeupater
    • By zeupater 12th Jun 19, 8:44 PM
    • 4,809 Posts
    • 6,478 Thanks
    zeupater
    I Keep reading this "Heat Pump tumble dryer" I thought people were just confused, or maybe its just me!, It seems the exact same system as a Condenser dryer to me, And that has been available for at least 15-20 years... At what point did they decide to re-brand it?


    According to the beko site It was possibly the germans 13 years ago.
    Originally posted by markin
    Hi

    Effectively there's a small heap pump in which the evaporator circuit (cold) creates a humidity condensing surface which is much colder than that in a standard condenser dryer (usually operating at cold water supply temperature) with the condensing circuit (hot) providing (some or all of) the warm air to the load for drying the laundry as opposed to relying on resistance elements ... this results in better use of resources as the HP is performing both functions more efficiently (heat at COP>1 and better formation of condensation on colder surface) ...

    HTH
    Z
    Last edited by zeupater; 12-06-2019 at 8:59 PM. Reason: grammar
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • markin
    • By markin 12th Jun 19, 9:03 PM
    • 655 Posts
    • 553 Thanks
    markin
    I must not have been looking to miss that development.



    But a quick look says they would save £33 a year. So certainly no point up grading if its in working order, with a cheap model at £340 taking 10 years to pay back.. if it last that long, and the £600+ models taking 20 years.


    Or as you are getting heat in the house on cold and damp days you are also saving on the gas, so possibly saving of only £15??
    Last edited by markin; 12-06-2019 at 9:09 PM.
    • Piddles
    • By Piddles 12th Jun 19, 9:14 PM
    • 103 Posts
    • 113 Thanks
    Piddles
    If you drive to work in an electric car and have solar PVs at home then you would have to work the night shift so your car can charge-up at home whilst the sun is shining. In this ideal world the battery in your electric car could also supply power to the house when the car is plugged-in at home.
    Businesses are included in the new Smart Export Guarantee scheme from 1st Jan 2020. AND employers can provide employees with tax free charging of their EV at work. Really. No benefit in kind liability (I'd provide the HMRC link but I'm not worthy yet....).

    So....employer puts PVs on his roof under the scheme and, assuming the employee has a shortish commute and a largish EV battery, they charge up while the sun shines at work, drive home, power their house from their EV battery after sunset leaving just enough juice to get back to work the next day....

    An excellent tax free perk.

    Except I work mostly from home
    • 1961Nick
    • By 1961Nick 13th Jun 19, 8:57 AM
    • 600 Posts
    • 2,730 Thanks
    1961Nick
    Businesses are included in the new Smart Export Guarantee scheme from 1st Jan 2020. AND employers can provide employees with tax free charging of their EV at work. Really. No benefit in kind liability (I'd provide the HMRC link but I'm not worthy yet....).

    So....employer puts PVs on his roof under the scheme and, assuming the employee has a shortish commute and a largish EV battery, they charge up while the sun shines at work, drive home, power their house from their EV battery after sunset leaving just enough juice to get back to work the next day....

    An excellent tax free perk.

    Except I work mostly from home
    Originally posted by Piddles
    I only noticed this week that the BIK rate for an EV drops to 2% in 2020/21.....that's a game changer.
    4kWp (black/black) - Sofar Inverter - SSE(141°) - 30° pitch - North Lincs
    Installed June 2013 - PVGIS = 3400

    Sofar ME3000SP Inverter & 5 x Pylontech US2000B Plus Batteries - 12kWh
    • Piddles
    • By Piddles 13th Jun 19, 9:29 AM
    • 103 Posts
    • 113 Thanks
    Piddles
    I only noticed this week that the BIK rate for an EV drops to 2% in 2020/21.....that's a game changer.
    Goodness... that's HUGE.

    The amount of tax the employee pays for a Nissan Leaf 40kWh goes from roughly £1,004 down to £128 for a 20% tax payer (or £1,661 to £255 for 40% tax payer).

    Boss, how about a Tesla?
    • 1961Nick
    • By 1961Nick 13th Jun 19, 9:51 AM
    • 600 Posts
    • 2,730 Thanks
    1961Nick
    Goodness... that's HUGE.

    The amount of tax the employee pays for a Nissan Leaf 40kWh goes from roughly £1,004 down to £128 for a 20% tax payer (or £1,661 to £255 for 40% tax payer).

    Boss, how about a Tesla?
    Originally posted by Piddles
    It's taken the Model 3 to the top of my list by some margin... & the timing is just about perfect too.

    It's a more expensive car than I have now, but would easily save me £7K a year.
    4kWp (black/black) - Sofar Inverter - SSE(141°) - 30° pitch - North Lincs
    Installed June 2013 - PVGIS = 3400

    Sofar ME3000SP Inverter & 5 x Pylontech US2000B Plus Batteries - 12kWh
    • Piddles
    • By Piddles 13th Jun 19, 10:09 AM
    • 103 Posts
    • 113 Thanks
    Piddles
    You'd better get your order in early. Everyone is going to want one once this becomes generally known!
    • 1961Nick
    • By 1961Nick 13th Jun 19, 10:15 AM
    • 600 Posts
    • 2,730 Thanks
    1961Nick
    You'd better get your order in early. Everyone is going to want one once this becomes generally known!
    Originally posted by Piddles
    Sales should rocket after 6th April 2020.
    4kWp (black/black) - Sofar Inverter - SSE(141°) - 30° pitch - North Lincs
    Installed June 2013 - PVGIS = 3400

    Sofar ME3000SP Inverter & 5 x Pylontech US2000B Plus Batteries - 12kWh
    • joefizz
    • By joefizz 13th Jun 19, 4:07 PM
    • 186 Posts
    • 172 Thanks
    joefizz
    Sales should rocket after 6th April 2020.
    Originally posted by 1961Nick

    If they make it past Jan 2020 ;-)


    To put it in context my mate has been on the waiting list since they were announced. He received the papers for it last month...
    ...still no word on when he will actually get the car...
    I suspect he will be visiting more often... just plug the car in there for me....
    • mmmmikey
    • By mmmmikey 15th Jun 19, 8:41 AM
    • 229 Posts
    • 350 Thanks
    mmmmikey
    Real life took over so it's a while since I posted anything on the PowerVault performance.....

    1. Overall position is much as expected, or if anything slightly better. I'm now feeling reasonably confident of breaking even within the life of the batteries, but certainly not expecting this to make me rich.

    2. When I bought it, I wasn't sure how it would cope this time of year when I have very low usage, i.e. would switching thresholds mean that I wouldn't be using enough to get the battery to start delivering? In practice this isn't a problem - as long as there's energy in the battery it will continue to deliver pretty much however low the load falls. But this comes at a cost in terms of efficiency, when it's running like this I would estimate that only about 50% of what it's delivering is being used, the rest being lost either in the inverter or going back to the grid as it doesn't adjust quickly enough (or accurately enough) to lower it's output at lower levels. The overall effect on the economics is slightly beneficial, because although it's inefficient running like this, it's "free" solar energy that is wasted.

    3. Assuming 1 cycle per day was pessimistic. Even without overnight charging on E7, I'm finding that there are lots of days when the battery charges up in the morning for use at lunchtime and then again in the afternoon for evening use. At this time of year I wouldn't normally use enough energy most days to take advantage of this, but we've had autumn weather in Lincolnshire over the last week and I've been getting 4 or 5 kWh a day use out of my 4 kWh battery, using what little solar energy there's been to take the chill off the house with electric heaters.

    4. I had started building an Arduino based circuit to switch the immersion heater off as the solar immersion controller (Solic) and battery don't work well together. But I've found it's so easy to do this manually that I'm not now going to bother. It's been easy to keep the water hot and battery charged, even during the last week of "autumn" weather. As soon as smart metering allows me to move from deemed export payments to actual export payments, I'll ditch the Solic anyway, as I pay less for E7 overnight than I get for export during the day.

    Hope this is of interest.....
    • Solarchaser
    • By Solarchaser 18th Jun 19, 1:30 PM
    • 56 Posts
    • 96 Thanks
    Solarchaser
    Good to know its keeping up with the low demand also.
    I've been a bit disappointed of late in the me3000sp, as when off too bed I have 40% of the battery, I expect it will discharge all night. But when house load falls under 150w, it stops discharging and starts using the grid, so I get up to having bought a kw of leccy, even though the battery could have covered it, which is disappointing.

    I am however seeing multiple partial discharges during the last month, which is great to see.
    The sunny /cloudy/sunny /cloudy days are really making the most of the batteries.
    • Reed_Richards
    • By Reed_Richards 19th Jun 19, 5:00 AM
    • 467 Posts
    • 276 Thanks
    Reed_Richards
    t when house load falls under 150w, it stops discharging and starts using the grid,
    Originally posted by Solarchaser
    That seems very poor. Are you sure it's the low power demand and not the time of use mode? If your battery was set to charge from the mains overnight but to take the SOC to only 30% (say) then posibly you might see the same effect, i.e. the battery does not charge or discharge overnight.
    Reed
    • Zarch
    • By Zarch 19th Jun 19, 8:48 AM
    • 274 Posts
    • 643 Thanks
    Zarch
    Good to know its keeping up with the low demand also.
    I've been a bit disappointed of late in the me3000sp, as when off too bed I have 40% of the battery, I expect it will discharge all night. But when house load falls under 150w, it stops discharging and starts using the grid, so I get up to having bought a kw of leccy, even though the battery could have covered it, which is disappointing.

    I am however seeing multiple partial discharges during the last month, which is great to see.
    The sunny /cloudy/sunny /cloudy days are really making the most of the batteries.
    Originally posted by Solarchaser
    Overnight use and covering the nightly baseload is one of the main reasons i'd want a battery. This is slightly off putting!

    Is this all batteries standard behaviour or just the Pylontech?
    17 x 300W panels on a 3.68 SolarEdge system in Sunny Sheffield.
    • 1961Nick
    • By 1961Nick 19th Jun 19, 9:17 AM
    • 600 Posts
    • 2,730 Thanks
    1961Nick
    Overnight use and covering the nightly baseload is one of the main reasons i'd want a battery. This is slightly off putting!

    Is this all batteries standard behaviour or just the Pylontech?
    Originally posted by Zarch
    I don't have this problem, but my then baseload is over 200w. If there's enough charge, I don't import anything overnight.

    Saying that, I'm slightly surprised, because this morning my batteries were supplying just 60w to make up the difference between generation & consumption.
    4kWp (black/black) - Sofar Inverter - SSE(141°) - 30° pitch - North Lincs
    Installed June 2013 - PVGIS = 3400

    Sofar ME3000SP Inverter & 5 x Pylontech US2000B Plus Batteries - 12kWh
    • Martyn1981
    • By Martyn1981 19th Jun 19, 11:23 AM
    • 8,685 Posts
    • 13,668 Thanks
    Martyn1981
    Overnight use and covering the nightly baseload is one of the main reasons i'd want a battery. This is slightly off putting!

    Is this all batteries standard behaviour or just the Pylontech?
    Originally posted by Zarch
    Same here, covering 100-150W night demand is a significant chunk of the import I'd want to displace.
    Mart. Cardiff. 5.58 kWp PV systems (3.58 ESE & 2.0 WNW)

    For general PV advice please see the PV FAQ thread on the Green & Ethical Board.
    • Reed_Richards
    • By Reed_Richards 19th Jun 19, 11:00 PM
    • 467 Posts
    • 276 Thanks
    Reed_Richards
    Is this all batteries standard behaviour or just the Pylontech?
    Originally posted by Zarch
    I doubt that it is anything to do with the battery; rather a function or malfunction of the inverter controlling it. It does not happen with my system and I would feel very cheated if it did.
    Reed
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