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On-grid domestic battery storage

edited 30 November -1 at 1:00AM in Green & Ethical MoneySaving
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  • SolarchaserSolarchaser Forumite
    414 posts
    100 Posts First Anniversary
    ✭✭
    Thats been my problem also, its what pushed me to batteries, exporting all day for no benefit,  to then buy it back an hour later.

    This thread may be helpful,  I did it a few months ago to outline what I had seen with a year of batteries. 

    https://forums.moneysavingexpert.com/discussion/6111409/a-year-with-home-batteries-and-more-solar-and-an-ev

    And in comparison to that thread, since ive been 3 months with 2 lux systems and 17kwh of batteries,  instead of buying 650kwh in last 3 months, (last years) I've bought 265kWh so around 90kwh a month, which will be mostly the electric showers, as the two inverters can't cover that, but these are the sunny months, so that won't last all year.
    West central Scotland
    4kw sse since 2014 and 6.6kw wsw / ene split since 2019
    24kwh leaf and Lux 3600 with 17kwh useable storage
  • Exiled_TykeExiled_Tyke Forumite
    415 posts
    Fourth Anniversary 100 Posts Name Dropper
    ✭✭
    Hi, I hope you don't mind me asking some real noob questions but interested in getting some battery storage.  I have a 3.6kw solar system which has been in for 5 years, I don;t have any software of anything clever that tells me what I am consuming (I don;t have a smart meter so can't assess real time usage) but am using approx 8400kw/h of electricity as well, that is what my electricity bill is telling me, so how do I go about assessing my requirements and doing a cost benefit analysis for buying some batteries?  Once I have determined that it makes sense, it probably won't pay for itself but I like the idea anyway which systems are recommended and are there any national installers (I'm in the Midlands) who are recommended?

    Thanks
    With your consumption profile I'm guessing that the economic case for a battery is going to be very poor indeed for your household.  I know mine won't come near paying for itself even though it's converted a lot of exported electricity into self-consumption.  I'd focus on matching your peak usage with peak production if you aren't already.  A key issue here it that on a good day at this time of year (if we ever get one of those again) the production will just about match consumption but once you get away from the peak months the system barely produces, you'll import almost all your electricity and the battery will be redundant. 
    Install 28th Nov 15, 3.3kW, (11x300LG), SolarEdge, SW. W Yorks.
    Install 2: Sept 19, 600W SSE
    Solax 6.3kW battery
  • SolarchaserSolarchaser Forumite
    414 posts
    100 Posts First Anniversary
    ✭✭
    Hi, I hope you don't mind me asking some real noob questions but interested in getting some battery storage.  I have a 3.6kw solar system which has been in for 5 years, I don;t have any software of anything clever that tells me what I am consuming (I don;t have a smart meter so can't assess real time usage) but am using approx 8400kw/h of electricity as well, that is what my electricity bill is telling me, so how do I go about assessing my requirements and doing a cost benefit analysis for buying some batteries?  Once I have determined that it makes sense, it probably won't pay for itself but I like the idea anyway which systems are recommended and are there any national installers (I'm in the Midlands) who are recommended?

    Thanks
    With your consumption profile I'm guessing that the economic case for a battery is going to be very poor indeed for your household.  I know mine won't come near paying for itself even though it's converted a lot of exported electricity into self-consumption.  I'd focus on matching your peak usage with peak production if you aren't already.  A key issue here it that on a good day at this time of year (if we ever get one of those again) the production will just about match consumption but once you get away from the peak months the system barely produces, you'll import almost all your electricity and the battery will be redundant. 
    I'm intrigued as to why you would say that?

    With high consumption of electricity, especially in the evening, as pulpdiction has said theirs is, the case for batteries is stronger not weaker imo, as the batteries will be cycled almost every day, making the offsetting of electricity cost at its maximum. 
    Add in a time of use tarrif for the winter months, like octopus agile, and you can lower the winter bill by say 50 - 60%

    For me, the case for batteries (and more batteries) is much stronger for high usage as you can maximise their usage, and weaker for low consumption as you would struggle to cycle the batteries every day, making the roi much longer.
    West central Scotland
    4kw sse since 2014 and 6.6kw wsw / ene split since 2019
    24kwh leaf and Lux 3600 with 17kwh useable storage
  • chamelionchamelion Forumite
    346 posts
    Part of the Furniture 100 Posts Name Dropper
    ✭✭
    Hi, I hope you don't mind me asking some real noob questions but interested in getting some battery storage.  I have a 3.6kw solar system which has been in for 5 years, I don;t have any software of anything clever that tells me what I am consuming (I don;t have a smart meter so can't assess real time usage) but am using approx 8400kw/h of electricity as well, that is what my electricity bill is telling me, so how do I go about assessing my requirements and doing a cost benefit analysis for buying some batteries?  Once I have determined that it makes sense, it probably won't pay for itself but I like the idea anyway which systems are recommended and are there any national installers (I'm in the Midlands) who are recommended?

    Thanks
    With your consumption profile I'm guessing that the economic case for a battery is going to be very poor indeed for your household.  I know mine won't come near paying for itself even though it's converted a lot of exported electricity into self-consumption.  I'd focus on matching your peak usage with peak production if you aren't already.  A key issue here it that on a good day at this time of year (if we ever get one of those again) the production will just about match consumption but once you get away from the peak months the system barely produces, you'll import almost all your electricity and the battery will be redundant. 
    I'm intrigued as to why you would say that?

    With high consumption of electricity, especially in the evening, as pulpdiction has said theirs is, the case for batteries is stronger not weaker imo, as the batteries will be cycled almost every day, making the offsetting of electricity cost at its maximum. 
    Add in a time of use tarrif for the winter months, like octopus agile, and you can lower the winter bill by say 50 - 60%

    For me, the case for batteries (and more batteries) is much stronger for high usage as you can maximise their usage, and weaker for low consumption as you would struggle to cycle the batteries every day, making the roi much longer.
    ditto this. 
    I'm a heavy user. I currently consume the vast majority of what I generate, with the little spare on top going into batteries. However I am soaking up loads of battery charge when it's cheap / free / paid for overnight, and my battery kicks in during the day to supply power if electricity prices are high - all of this controlled by octolux. On Octopus, I basically import 0 energy between the 4-7pm window when it's most expensive, and the battery trickles into the house if prices go higher than 7p/kwh. 


    5.41 kWp System, E-W. Installed Nov 2017
    Lux + 3 x 2.4kWh battery storage. Installed Mar 2020.
  • orreryorrery Forumite
    643 posts
    Part of the Furniture 500 Posts
    ✭✭
    Why not do a simple calculation to see what the limit is to the payback - i.e. that point which can never be reached? Assume that you can store and use all your export (a smart meter will measure that), and if you have economy 7 then assume you can displace all your peak usage with cheap rate. Even with these two unattainable figures, I couldn't see a payback.
    If you are doing it for personal satisfaction, or for environmental reasons then get on with it and work to maximise the payback later.
    4kWp, Panels: 16 Hyundai HIS250MG, Inverter: SMA Sunny Boy 4000TL, SolarImmersion
    Location: Bedford, Roof: South East facing, 20 degree pitch
    Nissan Leaf, TADO Central Heating control
  • cdunnecdunne Forumite
    39 posts
    Part of the Furniture 10 Posts Combo Breaker
    Thanks for this. Last month I purchased a SOFAR 'ME 3000SP' unit (from a supplier on eBay he was quick at responding pre-sales but hasn't responded to me after sales, my first point was the battery spacers shown on his eBay pictures weren't included. I've  realised the units are are quite 'clunky!' I've failed to get my phone to configure it to use my WiFi network (I get a page not found) when I try to login!
    Anyway until today it did seem to be working OK but today I isolated it (both from AC and DC to install the feed for my 'maintained' supply contactor from it's non grid output. I've failed to get it to re-energise since. I've proven that there is electricity on the 'grid connection' but the screen doesn't come no, nor do you hear the relays in it clunk closed when it works out it needs to charge / discharge. I'm also switching to the Agile Tariff (smart meter install Weds) and do NOT want the batteries to feed into a load I end up creating (I've a 40Amp feed to a second consumer unit in an office in the garden earmarked for this!) I don't think there is anyway to control the SOFAR via software so I was thinking of a simple hardware mod that switches the SOFAF CTs inputs to a dummy one suggesting that solar is generating and there is little load demand hence it will try to charge the batteries until they fill! Does the Lux have a similar setup of a solar and grid CT, is it easier to control via software? Can someone recommend a good model / hardware supplier of it. I would like to have the option to buy more batteries if they drop in price. Does it also cope with 8 packs like my existing one?
    Hopefully I can use the leverage of eBay to get a refund on the SOFAR!
    Thanks

    Chris
  • SolarchaserSolarchaser Forumite
    414 posts
    100 Posts First Anniversary
    ✭✭
    Hi Chris, from what you have said it sounds like the sofar either isn't seeing the batteries or isn't seeing the grid.
    From memory I think batteries need to be on (and running) and then you give it mains.
    Sofar won't really work with agile, however several of the forum members are using the lux running a script (not gonna lie i don't fully understand it) to integrate with octopus tarrifs, so it really sounds like thats more what you are looking for.

    Plus the lux switches on with either battery or mains (vs sofar requiring both).

    There was a good YouTube video on how to configure the WiFi using your phone by think renewables/ gigabiz/ homeswitch/infinity/pv pro, might still be there, was like 10 mins.

    I couldn't find it, but this one should help

    The solar man app can grab data from the sofar, but really the lux is better as you can actually set charge and discharge limits/cycles etc with the lux app, whereas the sofar can only show you information. 

    The lux can take 8 batteries yes, though Michael from think renewables etc did tell me they can now take unlimited batteries... ive not seen that confirmed anywhere. 
    West central Scotland
    4kw sse since 2014 and 6.6kw wsw / ene split since 2019
    24kwh leaf and Lux 3600 with 17kwh useable storage
  • htsofthtsoft Forumite
    2 posts
    First Post
    EVandPV said:
    I cobbled together a serial cab!e to use with the Pylons and the Batteryview app and I'm finding it quite useful not just for checking battery temperature (the Lux doesn't yet display this) but also for checking what's going on with all battery modules in the stack.
    It provides info such as voltage, charge current and capacity of each module plus the voltage of each cell which will be useful for checking for faulty cells.
    This is the cable I used ..... 

    Which I spliced to a modem cable with the wiring in this thread .....  


    Did you simply match the wire colours to make the RJ11 (using the green, red & orange of the USB converter in pins 2 3 4)? 

    Thanks
    t
  • EVandPVEVandPV Forumite
    722 posts
    500 Posts Name Dropper
    ✭✭
    htsoft said:
    EVandPV said:
    I cobbled together a serial cab!e to use with the Pylons and the Batteryview app and I'm finding it quite useful not just for checking battery temperature (the Lux doesn't yet display this) but also for checking what's going on with all battery modules in the stack.
    It provides info such as voltage, charge current and capacity of each module plus the voltage of each cell which will be useful for checking for faulty cells.
    This is the cable I used ..... 

    Which I spliced to a modem cable with the wiring in this thread .....  


    Did you simply match the wire colours to make the RJ11 (using the green, red & orange of the USB converter in pins 2 3 4)? 

    Thanks
    t
    Yes, pretty much. It's a while ago since I did it but I followed this diagram ......


    Scott in Fife, 3kwp pv SSW facing, Fronius inverter installed Jan 2012
    7.2kwh Pylontech battery storage with Lux ac controller
    Renault Zoe 40kwh, Zappi charger
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