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Solar PV battery options

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    #62
    graememk
    Moderators, Home & Garden Moderators Posts: 5,827 Mod ✭✭✭✭graememk


    DrPhilG wrote: »
    You may live to regret that lol.

    A question regarding the inverter. If going to a 2 inverter setup, is it better that they're the same type? With regards to export limitation etc.

    The export limit would only need to be on one inverter,

    So say you have 2 5kw hybrids battery on each.

    Worst case is both batteries are full and both are in full sun. only 1 of them has to limit its export.


    So with a storage inverter, it monitors the import export on the grid line and soaks up any excess. It also has a ct on the solar feed so it can calculate house load.

    I'm 99% sure it doesnt need the solar ct, if i disconnected it, im almost sure it will still charge the batteries when there is grid export detected.

    Ive noticed when the batteries are charging, It runs on a very slight grid import (only about 10w).



    Also I am not sure the hybrids have a DC -DC converter in them for charging the batteries, I have a feeling that the inverter puts everthing to AC then taps off whatever is excess to the batteries through its on board charger for the batteries.

    The battery section of it would have its own inverter too, to allow solar and battery power to be used simultaneously.

    If that theory is the case, you could be able to generate power from one inverter and store it on a second hybrid inverter. - its detecting excess and absorbs it.

    This is all theory crafting though. complete speculation.


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    #63
    DrPhilG
    Registered Users Posts: 12,201 ✭✭✭✭DrPhilG


    Thanks Graememk

    I wasn't planning on having a battery on each inverter, only reason I'm looking at 2 inverters is because a single phase 10kw inverter doesn't seem to be a thing, at least not for anything like a reasonable price.

    I'd be planning to have maxed out my storage plans before adding an inverter along with the additional panel capacity so would be looking at 2 if not 3 of the LiFePo4 batteries connected to my current system as a direct swap for the PylonTech.

    I see what you mean about only needing 1 inverter to limit export. Since 6kw will be allowed for export, then that would mean that all of one inverter's capacity could go to the grid. The second inverter would just need to know the total export, and then limit it's own contribution accordingly?


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    #64
    graememk
    Moderators, Home & Garden Moderators Posts: 5,827 Mod ✭✭✭✭graememk


    DrPhilG wrote: »
    Thanks Graememk

    I see what you mean about only needing 1 inverter to limit export. Since 6kw will be allowed for export, then that would mean that all of one inverter's capacity could go to the grid. The second inverter would just need to know the total export, and then limit it's own contribution accordingly?

    Yeah only need one to throttle.


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    #65
    DrPhilG
    Registered Users Posts: 12,201 ✭✭✭✭DrPhilG


    Those with the AliExpress cells, what physical size are they when assembled, and how many do you have?

    And given the lack of fire risk with LiFePo4 cells, anyone have them in the attic?

    The missus is dead against Leaf cells for fear that they'll blow the house up.


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    #66
    unkel
    Registered Users Posts: 64,837 ✭✭✭✭unkel


    DrPhilG wrote: »
    The missus is dead against Leaf cells for fear that they'll blow the house up.

    She's dead right. I don't like the idea of any lithium batteries in the house myself, apart from the ones you can't avoid like phones, tablets and laptops.

    My batteries are in a heavy duty steel comms cabinet outside. Covered on three sides by brick walls.


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    #67
    graememk
    Moderators, Home & Garden Moderators Posts: 5,827 Mod ✭✭✭✭graememk


    Each cell is (L*W*H):183*72*280mm

    So a row of 16 is about 1.2 M long.

    would weigh about 80-90 kg too.


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    #68
    championc
    Registered Users Posts: 6,068 ✭✭✭championc


    DrPhilG wrote: »
    Those with the AliExpress cells, what physical size are they when assembled, and how many do you have?

    A set of 4 is about one and a half times the height of a large car battery, with similar length and depth. So they are quite impressive cells, but quite large too.


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    #69
    Deagol
    Registered Users Posts: 1,700 ✭✭✭Deagol


    Don't take my head of with this question as maybe i'm mad but..

    Could you potentially use old laptop batteries? Was looking and seeing I can still get ~50w/h from an old Dell laptop battery. 100x of them.. combo of parallel and series connections would get me to 48v... but would internal resistances etc make it unworkable?


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    #70
    Ubbquittious
    Registered Users Posts: 6,182 ✭✭✭Ubbquittious


    Are ye lads running off the grid that ye have such large batteries or is there some intricate run the gas off the electricity and the electricity off the gas to save €200 going on?


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    #71
    Deagol
    Registered Users Posts: 1,700 ✭✭✭Deagol


    Ubbquittious wrote: »
    Are ye lads running off the grid that ye have such large batteries or is there some intricate run the gas off the electricity and the electricity off the gas to save €200 going on?

    With it likely you can get free electricty at certain times - it could be great to have a lot of battery power. Imagine in the winter time, you can charge up your battery from the grid on a Saturday and run your house off it and the little solar you might get for the week. Problem is the batteries cost more than the savings are likely to be doing that. Unless of course you can get the batteries at the right price.


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    #72
    Ubbquittious
    Registered Users Posts: 6,182 ✭✭✭Ubbquittious


    Deagol wrote: »
    With it likely you can get free electricty at certain times - it could be great to have a lot of battery power. Imagine in the winter time, you can charge up your battery from the grid on a Saturday and run your house off it and the little solar you might get for the week. Problem is the batteries cost more than the savings are likely to be doing that. Unless of course you can get the batteries at the right price.

    Nobody off the grid here so? This is what im really interested to find out more about. I know one dude who was off the grid but he crawled back on to it a few years ago. Not off the grid myself but this is the aim eventually and dont want to follow a similar fate

    It would take a long time for me to put €2,500 worth of electricity through a battery even if I got the electricity for free I don't really see the advantage for me personally.


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    #73
    graememk
    Moderators, Home & Garden Moderators Posts: 5,827 Mod ✭✭✭✭graememk


    Deagol wrote: »
    Don't take my head of with this question as maybe i'm mad but..

    Could you potentially use old laptop batteries? Was looking and seeing I can still get ~50w/h from an old Dell laptop battery. 100x of them.. combo of parallel and series connections would get me to 48v... but would internal resistances etc make it unworkable?

    you mean like this?


    Each one of them packs are 2.5kwh


    for sure wouldn't have them in my house, that guy has them in a steel container outside.

    Taking losses into account, charging at night and discharging during the day is saving about 50c/day over the winter.

    If I get onto energia's new ev rate, that would push it up to nearly 80c/day


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    #74
    Deagol
    Registered Users Posts: 1,700 ✭✭✭Deagol


    graememk wrote: »
    you mean like this?


    Each one of them packs are 2.5kwh


    for sure wouldn't have them in my house, that guy has them in a steel container outside.

    Taking losses into account, charging at night and discharging during the day is saving about 50c/day over the winter.

    If I get onto energia's new ev rate, that would push it up to nearly 80c/day

    Yeah -that's what I'm thinking of.

    My partilcular issue is that my radiator pump is .385kw. During the winter I'm not making anywhere enough from the solar panels to charge the battery to supply even a fraction of what I'm using. With the signs of us getting free power on certain tarriffs etc, I'm looking at how I could charge a big enough battery to offset at least some of the running costs.

    Has anyone looked into using a micro generator turbine and pump? Was thinking I have a two floor garage, wondering would it pay to put a water tank on two levels with a pump and a micro turbine. I could use the free power to lift the water up and then use the microgen to produce when needed, or even to charge the battery when empty to use the inverter as the power controller? Mad?


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    #75
    graememk
    Moderators, Home & Garden Moderators Posts: 5,827 Mod ✭✭✭✭graememk


    Ubbquittious wrote: »
    Nobody off the grid here so? This is what im really interested to find out more about. I know one dude who was off the grid but he crawled back on to it a few years ago. Not off the grid myself but this is the aim eventually and dont want to follow a similar fate

    It would take a long time for me to put €2,500 worth of electricity through a battery even if I got the electricity for free I don't really see the advantage for me personally.

    Would need a lot more solar to be off grid! esp when we use about 100kwh/week on the EV!

    But yeah thats the main sticking point, to put 2.5k through a battery. Easier to do when you have 10kwh, but with some of the ones being sold/quoted are only 2.4kwh or 5kwh, its a much harder sell!


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    #76
    unkel
    Registered Users Posts: 64,837 ✭✭✭✭unkel


    Deagol wrote: »
    Don't take my head of with this question as maybe i'm mad but..

    Could you potentially use old laptop batteries?

    Yes for sure. My first batteries were all made up from 18650 cells that I harvested out of "dead" laptop batteries that I got for free over the years.

    Lot of work in that, steep learning curve, you need to test the batteries for capacity, internal resistance, self-discharge rates, etc.

    If you are getting into batteries, that is a very useful learning experience though.


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    #77
    DrPhilG
    Registered Users Posts: 12,201 ✭✭✭✭DrPhilG


    unkel wrote: »
    She's dead right. I don't like the idea of any lithium batteries in the house myself, apart from the ones you can't avoid like phones, tablets and laptops.

    Even for the LiFePo4 ones that are said to have little/no fire risk?


  • Options
    #78
    idc
    Registered Users Posts: 548 ✭✭✭idc


    Deagol wrote: »
    With it likely you can get free electricty at certain times - it could be great to have a lot of battery power. Imagine in the winter time, you can charge up your battery from the grid on a Saturday and run your house off it and the little solar you might get for the week. Problem is the batteries cost more than the savings are likely to be doing that. Unless of course you can get the batteries at the right price.


    Just curious with these new smart tariffs like free electricity all day saturday or sunday what are the conditions? like if you did have large enough battery storage to literally fill it once a week and then use it and solar with little to no grid for the remainder of the week is that allowed or have the suppliers been smart and you need to use a certain amount from the grid the remaining days to avail of the free day?


  • Options
    #79
    irishchris
    Registered Users Posts: 3,170 ✭✭✭irishchris


    idc wrote: »
    Just curious with these new smart tariffs like free electricity all day saturday or sunday what are the conditions? like if you did have large enough battery storage to literally fill it once a week and then use it and solar with little to no grid for the remainder of the week is that allowed or have the suppliers been smart and you need to use a certain amount from the grid the remaining days to avail of the free day?
    I noticed in the terms for free Saturday or free Sunday it says subject to normal use and that they can remove the offer during contract if not. Now what normal use is considered I'm not sure


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    #80
    Zardaz
    Registered Users Posts: 64 ✭✭Zardaz


    idc wrote: »
    Just curious with these new smart tariffs like free electricity all day saturday or sunday what are the conditions? like if you did have large enough battery storage to literally fill it once a week and then use it and solar with little to no grid for the remainder of the week is that allowed or have the suppliers been smart and you need to use a certain amount from the grid the remaining days to avail of the free day?

    I just checked Board Gais Energy website, as I am also curious on this topic.
    They offer a "Free Sat" or "Free Sun" smart tariff option (9am to 5pm)

    In the terms and conditions PDF, it states:

    Fair Usage Cap on Free Energy units – there is a Fair Usage Cap on the monthly allowance of Free Energy units. This cap is set at 100kWh. Any excess units used above 100kWh will be charged at the Saturday or Sunday Day unit rate.


    So, 100KWh free a month (or ~23KWh per 7-day-week)

    Given that the average household usage per annum is in the order of 4500KWh per annum (not including widespread EV or heat pumps), which is about 12KWh per day, the best you can hope for is, with a AC coupled inverter and ~15KWh battery, is to store and carry over the equivalent of almost 1 additional "free" day per week. (so, you would get Sunday "Free" also)

    Or, looked at another way, you could fully charge a ~50KWh EV for free twice a month.


    Link to PDF


    I didn't check the other providers, but I suspect they would have similar restrictions. (Bonkers is going to have lost of fun trying to accurately track all this stuff.)


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    #81
    Ubbquittious
    Registered Users Posts: 6,182 ✭✭✭Ubbquittious


    Zardaz wrote: »
    I just checked Board Gais Energy website, as I am also curious on this topic.
    They offer a "Free Sat" or "Free Sun" smart tariff option (9am to 5pm)

    In the terms and conditions PDF, it states:

    Fair Usage Cap on Free Energy units – there is a Fair Usage Cap on the monthly allowance of Free Energy units. This cap is set at 100kWh. Any excess units used above 100kWh will be charged at the Saturday or Sunday Day unit rate.


    So, 100KWh free a month (or ~23KWh per 7-day-week)

    Given that the average household usage per annum is in the order of 4500KWh per annum (not including widespread EV or heat pumps), which is about 12KWh per day, the best you can hope for is, with a AC coupled inverter and ~15KWh battery, is to store and carry over the equivalent of almost 1 additional "free" day per week. (so, you would get Sunday "Free" also)

    Or, looked at another way, you could fully charge a ~50KWh EV for free twice a month.


    Link to PDF


    I didn't check the other providers, but I suspect they would have similar restrictions. (Bonkers is going to have lost of fun trying to accurately track all this stuff.)




    There would have to be a catch, wouldn't there?


    I'm still convinced the biggest way to save with all of this craic is not to spend 1000s on solar panels and batteries but to try and avoid consuming the electricity in the first place. I lived in one place where I was using <80kWh a month and another where I was being charged the low usage tarriff by ESB. Much easier to potentially give the utility companies the heave-ho at that level of usage



    Somewhere in a big glass head office in New York the head boys in I squared capital are laughing at people sinking so much money into grid-tied solar setups. When everyone has them installed they'll just petition the CRU to make things less favourable for people with that kind of setup.


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    #82
    Ubbquittious
    Registered Users Posts: 6,182 ✭✭✭Ubbquittious


    sebdavis wrote: »
    So your plan is not to use electricity at all? just to save a few quid. I can find a few issues with that.


    No. I had a good setup, I could casually leave the lights on and had my computing machine running 24/7 and still was consuming less than 80kWh without being careful or inflicting any misery upon myself. At that level of usage it might be feasible to spend what one would spend on standing charges and PSO levies on batteries instead. But one would need a second source of power like wind or micro-hydro.


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    #83
    sebdavis
    Closed Accounts Posts: 891 ✭✭✭sebdavis


    Ubbquittious wrote: »
    No. I had a good setup, I could casually leave the lights on and had my computing machine running 24/7 and still was consuming less than 80kWh without being careful or inflicting any misery upon myself. At that level of usage it might be feasible to spend what one would spend on standing charges and PSO levies on batteries instead. But one would need a second source of power like wind or micro-hydro.

    Sorry when I looked back on post it was snotty so deleted.

    I spent about 12-18 month trying to reduce electricty. I put in smart plugs etc so lights etc would turn off automatic. TV etc would shut down when not been used but still far too much electricity. I even have trained my 5 & 7 year old to use alexa to turn things on/off.....

    So Solar PV made sense


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    #84
    graememk
    Moderators, Home & Garden Moderators Posts: 5,827 Mod ✭✭✭✭graememk


    Yeah we have an outfarm and we can never switch to EI because of our low useage there.

    We need the grid because we have a well for water there, also we usually get an IFA deal with bord gaia with a decent cashback that covers most of the standing charges (although now that the pso is up to 88, the cashback doesn't cover near as much!)

    But at home, even now solar is starting to cover nearly all of my day useage. (Nearly hit 80kwh used in a 24 hr period!)

    Granted 60ish kwh was the ev on night rate though!

    Little to no day units were used in that screenshot.


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    #85
    DrPhilG
    Registered Users Posts: 12,201 ✭✭✭✭DrPhilG


    I'm getting the same response as others, BSL-battery will ship to the nearest port, either Belfast or Dublin.

    They don't get involved with import duty at all, so that would fall to me. In other words its not included, whereas with the AliExpress store it is.


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    #86
    DrPhilG
    Registered Users Posts: 12,201 ✭✭✭✭DrPhilG


    Also I spoke with Solis tech support and got the following advice re DIY batteries:
    Solis wrote:
    CANBus protocol is standard, for DIY purposes, make sure your BMS has a standard CAN Port with pin 45 is enabled in rj45 pin.


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    #87
    championc
    Registered Users Posts: 6,068 ✭✭✭championc


    DrPhilG wrote: »
    Also I spoke with Solis tech support and got the following advice re DIY batteries:

    So ask them if it will work with a DALY BMS

    Sofar absolutely said they would NOT support a.n. other BMS's


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    #88
    DrPhilG
    Registered Users Posts: 12,201 ✭✭✭✭DrPhilG


    Further update from the AliExpress seller.

    2 of the 16 pack was coming to €2,670 after discounts. I asked if there was any further discount available so he sent me a link for a 32 pack, for €2,691!

    It pays to haggle...

    Those who have purchased from these guys, a few more questions.

    1 - do they deliver to your door? I know that they bring them into Poland or somewhere, clear customs and then onwards. But does that second dispatch bring it to your home address or just to the nearest port like the BSL crew?

    2 - how secure is it, sending this amount of money across the world? First time buying on AliExpress so a little wary of being ripped off. Would credit card transaction still offer protection?


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    #89
    garo
    Registered Users Posts: 1,874 ✭✭✭garo


    I would be far more comfortable buying from AliExpress than the BSL crew. With AliExpress you can request a refund and you do get your money back - eventually - if something goes wrong and goods are not delivered.


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    #90
    E30M3
    Registered Users Posts: 312 ✭✭E30M3


    DrPhilG wrote: »
    Further update from the AliExpress seller.

    2 of the 16 pack was coming to €2,670 after discounts. I asked if there was any further discount available so he sent me a link for a 32 pack, for €2,691!

    It pays to haggle...

    Those who have purchased from these guys, a few more questions.

    1 - do they deliver to your door? I know that they bring them into Poland or somewhere, clear customs and then onwards. But does that second dispatch bring it to your home address or just to the nearest port like the BSL crew?

    2 - how secure is it, sending this amount of money across the world? First time buying on AliExpress so a little wary of being ripped off. Would credit card transaction still offer protection?

    I'm confused. It costs €21 extra after Haggling?


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    #91
    DrPhilG
    Registered Users Posts: 12,201 ✭✭✭✭DrPhilG


    garo wrote: »
    I would be far more comfortable buying from AliExpress than the BSL crew. With AliExpress you can request a refund and you do get your money back - eventually - if something goes wrong and goods are not delivered.

    Yeah that was my worry. So it's kinda like ebay. If something goes wrong you request a refund via AliExpress and they refund it.

    Getting close to pulling the trigger on 2 packs. So even more questions...

    1 - can the 2 packs join together to make one larger pack? I think this is answered here, but this leads me on to question 2.
    championc wrote: »
    You would need one per string of 16, although you could wire 2 cells in parallel, staying all in one string, (so making each cell 3.2v x 400A), but the BMS would have no control over the two individual cells since it would see them as one cell.

    2 - since I currently have 1 inverter, I would be joining these 2 packs as 2 cells in parallel as above. So is the 3.2v x 400a setup described above OK? Are there disadvantages to joining the 2 packs?

    3 - what else do I need to have in my shopping list to make this all complete. Busbars etc come with the cells. I need a BMS (no problem paying a little extra for the Heyo if it's worth it), and cables to connect the cells to the inverter. Anything else? Do I need a balancer if I have the BMS?


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