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  • FIRST POST
    • Coastalwatch
    • By Coastalwatch 13th Feb 18, 3:42 PM
    • 597Posts
    • 2,477Thanks
    Coastalwatch
    "Looking for a PV and EV solution"
    • #1
    • 13th Feb 18, 3:42 PM
    "Looking for a PV and EV solution" 13th Feb 18 at 3:42 PM
    I've an ageing deisel powered Ford Focus(ten years 75k miles) which has been brilliant but am thinking to replace it. Looking ahead Electric(second hand) seems a possible choice especially as we have two vehicles, so can use the other for long distances. We are retired with a mix of local journeys for school run etc and longer distances for holidays etc. I'm also keen on the idea of being self sufficient in generating electricity and considering combining the two. Our bungalow has roof of some 50 sq metres with a 22 degree pitch and being 20 degrees east of south facing. I'm thinking of filling the entire roof with panels in order to generate the max I can. On a good day in summer it could return circa 35kwh so I don't see a problem in supplying household needs(7kwh/day) and keeping the EV topped up. Am seeking quotations for systems of 4k only and the max that can be acheived also. Presumably I'd still get the FIT and export returns on the larger system so it would appear to me to be a sound financial investment. Battery storage is also an option but at current prices of 1000/kwh I'm not convinced of a sensible return. I note there is also a subsidy for installing a charging point. Would this be sensible? What does the team think? All replies gratefully accepted and considered.
Page 5
    • zeupater
    • By zeupater 17th Apr 19, 1:23 PM
    • 4,801 Posts
    • 6,469 Thanks
    zeupater
    That's not absolutely true. The software patch is indeed supposed to improve rapid charging but I hear the process still slows down when % battery is fairly high or if the battery gets hot. Not really a problem for me : since (or indeed before) the patch, I've never needed more than 2 RCs in the same day.
    Originally posted by EricMears
    Hi

    Isn't the fix really just down to Nissan 'relaxing' the battery protection algorithm which is supposed to extend cell life through limiting temperatures, so the patch is simply a trade-off between some new vehicle customers (those with regular high mileage journeys) being really annoyed now, to the same people or subsequent owners being really, really annoyed later ... some kind of customer focussed patch that must be - talk about kicking the can down the road! ...

    HTH
    Z
    "We are what we repeatedly do, excellence then is not an act, but a habit. " ...... Aristotle
    • EricMears
    • By EricMears 17th Apr 19, 1:43 PM
    • 2,449 Posts
    • 4,267 Thanks
    EricMears
    Hi

    Isn't the fix really just down to Nissan 'relaxing' the battery protection algorithm which is supposed to extend cell life through limiting temperatures, so the patch is simply a trade-off between some new vehicle customers (those with regular high mileage journeys) being really annoyed now, to the same people or subsequent owners being really, really annoyed later ... some kind of customer focussed patch that must be - talk about kicking the can down the road! ...

    HTH
    Z
    Originally posted by zeupater
    Quite so - definitely 'relaxing' rather than 'removing'.

    Agree that anyone regularly doing 3+ RCs per day is likely to suffer later; I can't imagine that me doing that once or twice a year is going to be quite so worrying.
    NE Derbyshire.
    4kWp S Facing 17.5deg slope (dormer roof).
    • Chesheer
    • By Chesheer 18th Apr 19, 9:24 AM
    • 6 Posts
    • 2 Thanks
    Chesheer
    That's not absolutely true. The software patch is indeed supposed to improve rapid charging but I hear the process still slows down when % battery is fairly high or if the battery gets hot. Not really a problem for me : since (or indeed before) the patch, I've never needed more than 2 RCs in the same day.
    Originally posted by EricMears

    It seems Nissan simply changed the level of max temperature :-)
    • Solarchaser
    • By Solarchaser 18th Apr 19, 7:35 PM
    • 53 Posts
    • 93 Thanks
    Solarchaser
    Having read this thread, it seems I'm about 9 months behind you coastal watch.

    I picked up a 15 plate leaf almost 6 months ago.
    Added another set of panels and inverter to try and reduce my electric spend, and charge the car for free.
    I looked at a zappi, but cant really justify its cost.
    The granny charger puts out a bit over 2.5kw, so in 6 hours the leaf is full... not that it's ever really that low, it's more often topped up from 50% to 90%
    The wife uses it for the school run and getting messages. So most days its sat in the drive waiting for a charge.
    And even if we needed it NOW and it was low, then a local fast charger is about 3-6 and so it would take some amount of emergency situations to justify the cost of the zappi.

    I have went for batteries, and am pretty happy with them. But I want more is the issue.
    I have a theoretical 10kwh but 4 of them arnt working, so trying to get the manufacturer of that system to refund me.
    The other 6 are doing a good job of reducing my overall bill, though I havent been through the best months with them yet, I'm finding throughout April they are fully charged by sometimes 10am, and usually non at the latest.
    It helps that the battery output is over what the granny charger takes, as it means that even when sun goes behind clouds, the leaf keeps free charging.... yeah there are round trip losses, but it was going to the grid anyway, so I'm not too bothered.

    My problem is I'm now sending down around 15-20kwh a day to the grid, so I'm interested in an iboost type of thing, but doing it in such a way that I'm not using the batteries to power the hot water if it goes cloudy.

    I like the idea of a thermal store, it makes the most sense but cant understand why a coil of tubing running through a heated liquid with some insulation costs so bloody much???

    V2g or more accurately v2h would be great for me, but despite links from 2015 saying it was almost here, it stills seems as far off as ever.

    Ovo's scheme seems the worst of all worlds to me, I just want to use my car battery to run the house at night, I'm not interested in emptying my car for someone 10 streets away
    • Coastalwatch
    • By Coastalwatch 18th Apr 19, 10:47 PM
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    • 2,477 Thanks
    Coastalwatch
    Hi Solarchaser, I don't know about being 9 months behind, you're ahead when it comes to home storage! Like you, I just want sufficient energy stored to see us through to morning or, maybe just midnight without resorting to the grid. If we could all do that then demand upon the grid would reduce thus alleviating the need for the likes of Ovo and EDF to discharge our stores to cope with evening peak demand.

    I'm being patient regarding battery purchase until prices are more realistic and the technology to control the charge/discharge cycles has matured. For me it's early days and with a few wrinkles still to be sorted.
    In a way that is what has spurred us on to fit the thermal store as suggested by others here. In the past we've consumed on averag 100 kWh's gas a month for hot water alone, approx 3.3 kWh's per day. If we use solar for this in place of gas then effectively we've gained our storage via a different medium and at about a third the cost of a battery per kWh that is.

    Just one further question, if you've an EV, are you not eligible for a government grant towards the purchase and installation of a charger! From memory the grant covered most of the cost of the Zappi leaving us to pick up the bill for the remainder and installation!
    Since acquiring our EV last July we've only had to charge away from home on five occasions. Two being at a friends via the granny cable while the remaining three were at charging stations. When I last did a monthly check the 4350 or so miles covered since purchase were at an average cost of 1.2p/mile.
    East coast, lat 51.97. 8.26kw SSE, 23 pitch + 0.59kw WSW vertical. Nissan Leaf plus one dirty diesel. Still waiting for V2H and home storage to become available at sensible cost.
    • Solarchaser
    • By Solarchaser 19th Apr 19, 11:43 AM
    • 53 Posts
    • 93 Thanks
    Solarchaser
    I know about the grant but from reading forums, the dumb chargers are covered in cost, but the zappi seemed to be around 450 extra.

    Without the technology to cascade, I wouldn't want to find the sun has gone down and my batteries are emptying to fill the ev.
    I dont mind that happening when the sun is out and the batteries can be topped back up, but wouldn't be happy with it doing it later in the day.

    What I really want is a ct clamp or meter to say, hey theres excess going to grid, ok charge home batteries.... hey theres still excess, ok charge ev... hey theres still excess, ok heat thermal store.

    At the moment I see lots of stories of batteries emptying to charge ev, or heat water.

    This solution must be straight forward, I see the zappi and Eddie do the car plus water, but theres a few reports of that not working properly either.

    When my two battery systems do work, about 50% of the time they work properly, and the other 50% the sofar starts charging off the growatt batteries because the growatt is so much slower to react.

    The more I think about this, the more I see it has to be an inverter manufacturer that needs to build this system if it's to be inclusive.

    However if someone could build a simple circuit with checks and delays, that would work too.
    So leave batteries to do their thing.

    Have a circuit that looks at excess to grid being maintained for say 10 seconds, and then switches on vehicle charging, but once every 15 mins, switches off for 30 seconds, checks there is still excess and starts again, this would stop the situation of the batteries emptying to fill the EV.
    Again maybe a second circuit that says 30 seconds after first circuit is activated, if there is still excess, the heating element is activated, and when the ev circuit is switched off at the 15 min point, so is the element, and whole thing starts again.
    If at any point during the 15 min cycle, the export turns to import, the whole thing stops.

    I'm sure someone could design a circuit like that fairly easily, maybe 20 years ago, when I was into electronics, I could have, but definitely not now
    • Solarchaser
    • By Solarchaser 19th Apr 19, 12:12 PM
    • 53 Posts
    • 93 Thanks
    Solarchaser
    I should say as well, I have only the 3.3kw leaf, so I dont gain that much speed of charge over the granny charger, whereas if you have the 6.6kw you will gain alot more.

    Just looking at what you said about gas.
    So if you are saving 3.3kw of gas a day, that's equivalent to 1.1kw of electricity (based on roughly gas being 1/3rd cost of electric.)

    For me to have 6kwh of useable battery and the inverter would now be about 3k going on Ebay prices from last week, (sofar me3000sp and 7.2kw of pylontech batteries) so 500/useable kWh, now obviously I dont get to use that 6kwh every day, but barring a couple of really moody days, it was charged all the way in March, and has been every single day in April, so I'm definitely saving at least 6kwh /day in April, and I say at least, because of the discgarching mid day to cut the peaks of the tumble dryer and washing machine the wife has on together, and several times a day.

    It's all too new at this point to say how much I'm saving for the year, but I cant imagine it being less than 300, giving it a 10 year pay back.
    I was using 5500kwh of electricity though, so appreciate I'm a higher than average user.
    And for me the arguement for batteries is stronger the more electricity you use, and weaker the less you use.... as there is less to save.

    Some of what I cant save is the fact that I have 2x 9.6kw electric showers, so no battery system that could cover that being anywhere close the financially viable, so maybe switching to mixers... though that's cutting into walls and running extra plumbing, and if I'm doing that, I'm really starting to look at hot water tanks.

    Can I ask about your store?
    I dont want to maintain a system, and I dont want concerns about things growing, so for me the thermal store is much more attractive than a vented or unvented cylinder, but I just dont get how these things can be 1500.

    But you know, it's one of those things where I'm wondering if I'm missing something.
    My understanding is you have a treated fluid which is contained and that's what's heated.
    It never comes into contact with the potable water so no risks there.
    You have a separate coil which runs through the heated fluid, your potable water runs through it and is heated.

    Why is that 1500-2000 not 400-500?

    There are 6 people in my house, what sort of volume do you think I would need to cover their use?
    • Coastalwatch
    • By Coastalwatch 19th Apr 19, 12:57 PM
    • 597 Posts
    • 2,477 Thanks
    Coastalwatch
    Can I ask about your store?
    I dont want to maintain a system, and I dont want concerns about things growing, so for me the thermal store is much more attractive than a vented or unvented cylinder, but I just dont get how these things can be 1500.

    But you know, it's one of those things where I'm wondering if I'm missing something.
    My understanding is you have a treated fluid which is contained and that's what's heated.
    It never comes into contact with the potable water so no risks there.
    You have a separate coil which runs through the heated fluid, your potable water runs through it and is heated.
    Why is that 1500-2000 not 400-500?
    There are 6 people in my house, what sort of volume do you think I would need to cover their use?
    Originally posted by Solarchaser
    Hi, with regard to hot water heating then to replace 3.3kWh of gas I'd still need 3.3kWh of leccy to replace it unless I install an ultra expensive water based ashp.


    In terms of the seemingly high cost of a thermal store then I can't answer that, other than to suggest complexity(internal coil length etc) and scale of manufacture. I suspect volumes as yet are insufficient to get manufacturing costs down to the levels enjoyed by traditional water cylinders.
    The link below will take to a website that mmmikey suggested I look at and it's from there where I shall be acquiring the tank that best suits our purposes. They manufacture various sizes of tank from domestic through to commercial so will probably have a suitable size for your household. Prices start from under 1k for a 160litre tank although you will obviously need something larger. I believe there is a feature on the website which you feed your requirements into and it suggests what size tank you may need.

    You are correct, as far as I'm aware, in that the tank contains the fluid which transfers heat to the incoming water with the two mediums totally seperated otherwise.


    www.advanceappliances.co.uk/product-listing/8-thermal-store/
    Last edited by Coastalwatch; 19-04-2019 at 1:02 PM. Reason: link added!
    East coast, lat 51.97. 8.26kw SSE, 23 pitch + 0.59kw WSW vertical. Nissan Leaf plus one dirty diesel. Still waiting for V2H and home storage to become available at sensible cost.
    • Solarchaser
    • By Solarchaser 19th Apr 19, 3:44 PM
    • 53 Posts
    • 93 Thanks
    Solarchaser
    Yeah I understand you would still have to heat the water, my point was more that batteries would give you a bigger "per day" return than the water store, as with the water you save say 15p a day not using gas, but with the batteries you could save 80p a day on electric usage, I was mentioning it because you were saying how the battery cost per kw was still too high.

    The reality for me, is I've no idea how much gas I use per day, had a smart meter fitted over 2 years ago, worked for less than 3 months, and I'm too lazy to open the box every day to check.

    I think I'm trying to convince myself that a thermal store is no good for me, while simultaneously trying to convince myself to get one.

    Yeah point taken about manufacturing costs vs demand, probably is that.

    Thanks very much for the info, I'll have a look at the link.
    And looking forward to reading about your experience with the thermal store.

    Kev
    • Coastalwatch
    • By Coastalwatch 13th Jun 19, 10:21 PM
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    • 2,477 Thanks
    Coastalwatch
    Gosh, doesn't time fly! Nearly two months have passed and I've only just installed the store, we went for the 210 litre version. Like mmmikey's it fitted into the old airing cupboard with just enough space beside it for the ironing board and vac cleaner plus a couple of shelves above. At 1750mm tall its' a bit of a stretch to reach those above but, hey ho better than none at all. Installation went as per instructions although I did need to source a pressure reduction valve, inhibitor and water treatment unit from elsewhere.

    I've charged the unit to nearly full with pressure limited to 3 bar as per instructions. As yet to apply any heat due to there being little surplus solar at present. No leaks so far!
    Will update further once heated to recommended temperature circa 65-75C. Also need to sort a controller to make best use of excess solar which may mean that it requires it's own specific supply direct from the consumer unit!
    East coast, lat 51.97. 8.26kw SSE, 23 pitch + 0.59kw WSW vertical. Nissan Leaf plus one dirty diesel. Still waiting for V2H and home storage to become available at sensible cost.
    • markin
    • By markin 27th Jun 19, 2:52 AM
    • 636 Posts
    • 546 Thanks
    markin
    Gosh, doesn't time fly! ............................................. No leaks so far!
    Will update further once heated to recommended temperature circa 65-75C. Also need to sort a controller to make best use of excess solar which may mean that it requires it's own specific supply direct from the consumer unit!
    Originally posted by Coastalwatch



    Is it up to 65C yet?
    • Coastalwatch
    • By Coastalwatch 27th Jun 19, 7:20 AM
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    Coastalwatch
    Is it up to 65C yet?
    Originally posted by markin
    Hi and thanks for the reminder.


    Yes, it's been heating the DHW since with the element thermostat set on max, 75C, although the temp shown on the gauge sited higher up the tank peaks around 80C.
    I'll probably knock the stat back a notch for the winter months but with excess solar at this time of year I'm not in a hurry.

    Still have to sort a controller to make best use of Solar. All in good time!
    East coast, lat 51.97. 8.26kw SSE, 23 pitch + 0.59kw WSW vertical. Nissan Leaf plus one dirty diesel. Still waiting for V2H and home storage to become available at sensible cost.
    • Solarchaser
    • By Solarchaser 1st Jul 19, 10:10 PM
    • 53 Posts
    • 93 Thanks
    Solarchaser
    Hi, I understand about prv, lucky you having more than 3 bar available. :-D

    But why a water treatment plant and inhibitor?
    I was under the impression you are in Bonnie Scotland, so should have no issues with hard water or limescale?

    If I've picked that up wrong, apologies.

    I'm currently waiting on a refund for my faulty hybrid system, so have just 6kwh of batteries just now, and when I look at how much I'm exporting daily it really makes me pine for a hot water system lol
    • Coastalwatch
    • By Coastalwatch 2nd Jul 19, 1:35 PM
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    • 2,477 Thanks
    Coastalwatch
    Hi, I understand about prv, lucky you having more than 3 bar available. :-D
    But why a water treatment plant and inhibitor?
    I was under the impression you are in Bonnie Scotland, so should have no issues with hard water or limescale?
    Originally posted by Solarchaser
    Oh for soft water like in Scotland, here in bonny Suffolk it's anything but. Neverless I'm consoled by the climate here which tends to help offset the disparity.
    Afraid I baulked at installing a salt based water treatment system due to space constraints and cost. Both initial and running, where I understand the latter can amount to circa 100/annum. I settled for an Eddy unit which, while not actually removing limescale, does reduce it's effects being more compact and less costly too.

    As for a battery, well, I've one sitting on the drive and just require a cost effective interface to go between it and our home.
    East coast, lat 51.97. 8.26kw SSE, 23 pitch + 0.59kw WSW vertical. Nissan Leaf plus one dirty diesel. Still waiting for V2H and home storage to become available at sensible cost.
    • Solarchaser
    • By Solarchaser 2nd Jul 19, 9:21 PM
    • 53 Posts
    • 93 Thanks
    Solarchaser
    Ahh ok, dont know why I thought you were in Scotland, the additions make perfect sense for Suffolk.

    I'm 100% with you on the EV v2h, I just cant understand why there isn't a cheap solution from either EV manufacturers (surely makes EV's more attractive) or big power suppliers for grid balancing etc.

    Or even people like the inventors of Zappi etc.
    • Coastalwatch
    • By Coastalwatch 16th Jul 19, 6:21 PM
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    • 2,477 Thanks
    Coastalwatch
    Hi and thanks for the reminder.
    Yes, it's been heating the DHW since with the element thermostat set on max, 75C, although the temp shown on the gauge sited higher up the tank peaks around 80C.
    I'll probably knock the stat back a notch for the winter months but with excess solar at this time of year I'm not in a hurry.
    Originally posted by Coastalwatch
    It's been in operation a month now during which time our gas consumption has dropped to about half of the previous lowest summertime figure recorded of 89 kWh's.
    Of the 45 kWh's consumed the majority was probably due to the gas hob, but a smaller proportion perhaps due to DHW drawn off by use of the sink in the en suite, plus some from leaving the pre heat option on the combi boiler operational!
    With that now de-activated we'll see what difference might occur when taking next months figures.
    At the commencement of this thread I'd thought no further than what car to purchase next. What a journey it's been and continues to this day as we've now set our sights on relying entirely on renewable energy for all our heating, transportation and domestic needs.
    If we make it through the coming winter without resorting to the gas combi boiler then we've only to replace the gas hob to complete another step along the way.
    East coast, lat 51.97. 8.26kw SSE, 23 pitch + 0.59kw WSW vertical. Nissan Leaf plus one dirty diesel. Still waiting for V2H and home storage to become available at sensible cost.
    • Solarchaser
    • By Solarchaser 17th Jul 19, 12:01 AM
    • 53 Posts
    • 93 Thanks
    Solarchaser
    Thanks for the update.
    I'm finding myself more and more drawn to the thermal store.
    On a whim I phoned my combi manufacturer and it turns out that I can feed it with 50c water, so could definitely use the store to heat the water in summer, and take some of the chill of in winter.

    I'd convinced myself I didnt want to run that way, as it involves opening a wall to run pipes, and wife wont be too happy, but I think I'm just going to have to do it, and ask forgiveness later.
    • Reed_Richards
    • By Reed_Richards 17th Jul 19, 5:52 AM
    • 466 Posts
    • 276 Thanks
    Reed_Richards
    ... I phoned my combi manufacturer and it turns out that I can feed it with 50c water, ....
    Originally posted by Solarchaser
    I did not think that any combi boiler could cope with more than 30 C water on the input side. What model do you have?
    Reed
    • Coastalwatch
    • By Coastalwatch 17th Jul 19, 9:27 AM
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    • 2,477 Thanks
    Coastalwatch
    Thanks for the update.
    I'm finding myself more and more drawn to the thermal store.
    On a whim I phoned my combi manufacturer and it turns out that I can feed it with 50c water, so could definitely use the store to heat the water in summer, and take some of the chill of in winter.

    I'd convinced myself I didnt want to run that way, as it involves opening a wall to run pipes, and wife wont be too happy, but I think I'm just going to have to do it, and ask forgiveness later.
    Originally posted by Solarchaser
    For sure, a version of the Thermal store is available for indirect heating from gas or oil too if you wish to procede in that direction. However, for me it was an additional complication with added capital outlay.

    I took the view that, as we need to do away with gas eventually, then to go straight for the immersion only version for simplicity and cost. Understanding that in winter months we may be paying extra for DHW due to absence of sunshine at times. Guess I'll find out how much extra during the coming winter.
    East coast, lat 51.97. 8.26kw SSE, 23 pitch + 0.59kw WSW vertical. Nissan Leaf plus one dirty diesel. Still waiting for V2H and home storage to become available at sensible cost.
    • Solarchaser
    • By Solarchaser 17th Jul 19, 3:39 PM
    • 53 Posts
    • 93 Thanks
    Solarchaser
    Mine is a potterton promax.

    Coastalwatch, I was toying with solar thermal panels on the roof too, still have room.
    Might get rhi too.... but I need to research it and see if its viable
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