Grid-tied or off-grid. Please consider ...





Page 1 of 2 1 2 LastLast
Results 1 to 20 of 38
  1. #1
    Join Date
    Mar 2017
    Location
    Darling
    Posts
    108
    Thanked: 46

    Default Grid-tied or off-grid. Please consider ...

    I need some advice on whether to go off-grid or grid-tied. I know conventional wisdom says grid-tied in municipal areas, but based on our equipment what would you do? (I do not want to argue the merits of our current investment, just looking for your insight)

    We have recently bought 2x 6Kwh LiFePO4 battery banks, and 12x Canadian Solar 410w panels. We do want to be as independent as possible from the grid, but will keep the existing prepaid as a backup.

    We also have a legacy Axpert 5k offgrid inverter(/ups) bought in Jan 2019 with 4x Deltec 100Ah flooded batteries.

    Having relocated to the Western Cape we are keen to be compliant with the SSEG policies and although we do not fall under CoCT, if we add another inverter it must be an approved device.

    We can connect all the panels to the existing inverter MPPT (80A, 145V dc) and it should serve our needs.

    However, in order to meet compliance goals we are looking at aKodak 4.6 grid tied inverter ( same bones as the Axpert).

    If we go off-grid we could sell the Axpert and replace it with the Kodak (MPPT 80A, 450V) and even parallel 2 inverters.

    Why should i not go off-grid and just add another Axpert to my system, paralleling them? Please don't talk about electricity cost from grid as that is no longer a factor to be considered.




  2. #2
    Join Date
    Nov 2015
    Location
    Cape Town
    Posts
    587
    Thanked: 641

    Default Re: Grid-tied or off-grid. Please consider ...

    Asking the question obviously assumes that you have absolutely ensured that your loads, and load profiles, are well managed, done with foresight, catered for by the 2 x 6kWh lithium banks, the 12 x 410w panels having enough to power daytime the loads and recharge the 12kWh bank, the inverter/s max power rating matches your peaks ... so there is no need to discuss that ad infinitum, correct?

    And you kind of removed the most salient discussion point around grid-tied vs off-grid i.e. Eskom costs, right?

    But, lets work with that.

    My first reaction was:
    Is going off-grid, when you are keeping the PAYG link, a WANT or a NEED?

    Then I thought: Hold on, is this maybe a case of asking the question the other way around i.e. I bought all this, is it enough to go off-grid?


    The answer lies quite simply, in my mind, with the question you need to answer for yourself:
    When you have a Cape winter with a couple of weeks worth of non-solar-system weather over a period of a year, what is your plan to power through them?
    What will that cost you?

    And because you said, I quote "... will keep the existing prepaid as a backup ... " you need to add the cost of the monthly PAYG connection fee, to the costs incurred above.

    And you also did not lose sight of the fact that you need to recoup all the above expenditure ASAP, because solar equipment, they don't last indefinitely, nope, they don't.

    Which then begs the question to be asked:
    Why would you want to go off-grid in the first place, and not grid-tied, if you have a PAYG connection and probably paying <R2 per unit?
    Last edited by the_terrible_triplett; 2020/06/25 at 01:09 AM.
    Political Correctness
    Political Correctness is a doctrine, fostered by a delusional illogical minority, rabidly promoted by a unscrupulous mainstream media which holds forth the proposition that it is entirely possible to pick up a turd ... by the clean end!

    Saw this in a pub - no idea why the wife does not see it so:
    I'm not opinionated ... I'm just always right!

  3. #3
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    63
    Posts
    1,579
    Thanked: 538

    Default Re: Grid-tied or off-grid. Please consider ...

    AFAIK the Axpert is not compliant and your one suggestion is to buy a 2nd one. They also not grid tied.

    I would rather get the Kodak that can be used as grid tied. This will also help to get through those rainy periods where you want to fall back on the grid instead of using a costly genny. This way you can use any load during the day and limit the grid contribution and have battery banks full most days from solar which seems to be spot on for your load profile. This inverter is also approved.

    You could also sell the Axpert and get a proper system configured for what you try to achieve.

  4. The Following User Says Thank You to ekkekan For This Useful Post:


  5. #4
    Join Date
    Dec 2008
    Location
    Windhoek
    Age
    61
    Posts
    410
    Thanked: 110

    Default Re: Grid-tied or off-grid. Please consider ...

    Asking as someone who does not have prepaid - does net metering come into the picture? I.e. receiving credit from the local authority for putting current back into the grid.

  6. #5
    Join Date
    Oct 2010
    Location
    Pretoria
    Age
    61
    Posts
    1,562
    Thanked: 522

    Default Re: Grid-tied or off-grid. Please consider ...

    What I have done is basically what you have, except I'm running two Axpert in parallel.

    To get grid backup without grid tied equipment I fitted a changeover switch. That should take care of the NRS issues.

    So now you run on your solar system, and for the odd times you need the grid you just change over, no funnies, no current transformers, no split DB.

  7. #6
    Join Date
    Nov 2009
    Location
    Edenvale
    Age
    53
    Posts
    1,830
    Thanked: 1270

    Default Re: Grid-tied or off-grid. Please consider ...

    Phone Segen and ask their support people what percentage of their returns/Issues are with Kodak Inverters...

  8. #7
    Join Date
    Apr 2016
    Location
    Johannesburg
    Age
    69
    Posts
    409
    Thanked: 64

    Default Re: Grid-tied or off-grid. Please consider ...

    What does it cost to have the PAYG facility if you don't use any electricity??

  9. #8
    Join Date
    Dec 2019
    Location
    Cape Town
    Posts
    166
    Thanked: 40

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by NewLandy View Post
    Phone Segen and ask their support people what percentage of their returns/Issues are with Kodak Inverters...
    To add, if you can get hold of them. Forums and fb is flooded with complaints of no responds from them, installers that have paid for stock but didn't received there stuff, and we will not even get close to the repair complaints.

  10. #9
    Join Date
    Nov 2015
    Location
    Cape Town
    Posts
    587
    Thanked: 641

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by Sadi View Post
    Asking as someone who does not have prepaid - does net metering come into the picture? I.e. receiving credit from the local authority for putting current back into the grid.
    Netmetering can only be done with a Bi-directional meter, costing, in Cpt, about R 12 000+, with a contract signed between you and the Munic on the terms.
    On top of that cost, there is a +-R15 per day connection fee, in Cpt.
    Which makes netmetering not something we want to talk about.

    Quote Originally Posted by faniedup View Post
    ... two Axpert in parallel.

    ... I fitted a changeover switch. That should take care of the NRS issues.
    Nope, the switch actually makes them illegal.

    The problem NRS and SANS are dealing with, in very very basic terms, are solar panels connected to the grid via a DB using a inverter.

    All they are asking for is that that inverter connected to the grid, via a DB, whilst connected to solar panels, has to have a NRS certification.
    Just like the old SABS stamp of approval ... Axperts have no certification that I could find, bar the one they give themselves. I tried, believe me.

    So when you change that changeover switch over to switch a Axpert back to the grid, with the panels connected to that Axpert, you are right back where the problem starts, a non-NRS approved inverter connected to the grid via a DB.

    So no, it is not legal. Axperts are sold, as per Voltronic, as off-grid inverters. So no changeover switch if you want to be 100% legal.

    Quote Originally Posted by NewLandy View Post
    Phone Segen and ask their support people what percentage of their returns/Issues are with Kodak Inverters...
    O yes, very salient point to ponder on. There are other brands also to do that with ... but lets not go there.

    Quote Originally Posted by Gerlach View Post
    To add, if you can get hold of them. Forums and fb is flooded with complaints of no responds from them, installers that have paid for stock but didn't received there stuff, and we will not even get close to the repair complaints.
    Adding to that, I've picked up stompies (to be confirmed) that Kodak is a Voltronic brand, a Axpert copy. Just double check that too.

    Quote Originally Posted by Richard Mackay View Post
    What does it cost to have the PAYG facility if you don't use any electricity??
    In my case, R150.00 + VAT per month just to have the connection to the grid.
    Connection fees also differ between areas, towns, cities, provinces, few are less than mine, quite a few are a lot more, as some Munic's slap on even more "fees".
    Last edited by the_terrible_triplett; 2020/06/25 at 09:46 AM.
    Political Correctness
    Political Correctness is a doctrine, fostered by a delusional illogical minority, rabidly promoted by a unscrupulous mainstream media which holds forth the proposition that it is entirely possible to pick up a turd ... by the clean end!

    Saw this in a pub - no idea why the wife does not see it so:
    I'm not opinionated ... I'm just always right!

  11. #10
    Join Date
    Apr 2016
    Location
    Johannesburg
    Age
    69
    Posts
    409
    Thanked: 64

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by the_terrible_triplett View Post
    In my case, R150.00 + VAT per month just to have the connection to the grid.
    Connection fees also differ between areas, towns, cities, provinces, few are less than mine, quite a few are a lot more, as some Munic's slap on even more "fees".
    I reckon R150 pm is worth it to have a fallback position when your off grid system has failed for some reason or other..
    Last edited by Richard Mackay; 2020/06/25 at 09:52 AM.

  12. #11
    Join Date
    Nov 2015
    Location
    Cape Town
    Posts
    587
    Thanked: 641

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by Richard Mackay View Post
    I reckon R150 pm is worth it to have a fallback position when your off grid system has failed for some reason or other..
    Yes, it is.

    But that begs the question, why go "off-grid" in the first place if you have Eskom?
    Why when you can drop your Eskom costs to <R600 (connection fee incl), and even lower than that if you are really good, really disciplined having gone grid-tied?
    EDIT: Why go near solar if you can drive your Eskom usage down to <R600 (connection fee incl) per month, having spent not a cent, just pure discipline?

    The sums are simply not in favour of going off-grid in cities, not by a long shot. For when you take all the cost factors into consideration, your are looking at MANY years you have to run without spending one cent on repairs/replacements to recoup that cost just to break even. I think it comes to between 10-15 years before you break even.

    Versus you drive the ROI to break even in 5 years or less ... within the warranty period of the core equipment like batts, inverters.
    And then you pray and hope it all last another 5-10 years so that you can save like mad to have the funds in cash to replace it all again.

    With grid tied you can do that faster, cheaper, than going off-grid.

    But the rules said, we are not allowed to discuss that ...
    Quote Originally Posted by wims_za View Post
    ... I know conventional wisdom says grid-tied in municipal areas, but based on our equipment what would you do? (I do not want to argue the merits of our current investment, just looking for your insight)
    So to answer the question asked, what would I do with those panels and batts?
    I would go 5kva grid tied ... No. Feeding, Back ... and shave off every single watt I can off the Eskom bill to recoup the monies spent as soon as humanly possible.

    EDIT:
    Hold on ...

    UNLESS, without spending one more cent on big items, with the equipment as is, you can go off-grid.
    Last edited by the_terrible_triplett; 2020/06/25 at 10:21 AM.
    Political Correctness
    Political Correctness is a doctrine, fostered by a delusional illogical minority, rabidly promoted by a unscrupulous mainstream media which holds forth the proposition that it is entirely possible to pick up a turd ... by the clean end!

    Saw this in a pub - no idea why the wife does not see it so:
    I'm not opinionated ... I'm just always right!

  13. #12
    Join Date
    Oct 2010
    Location
    Pretoria
    Age
    61
    Posts
    1,562
    Thanked: 522

    Default Re: Grid-tied or off-grid. Please consider ...

    Nope, the switch actually makes them illegal.

    The problem NRS and SANS are dealing with, in very very basic terms, are solar panels connected to the grid via a DB using a inverter.



    Nope, the switch disconnect my Axpert from the Grid, there is no connection between them and grid. My solar system is installed as if it were a petrol generator.

  14. The Following User Says Thank You to faniedup For This Useful Post:


  15. #13
    Join Date
    Oct 2013
    Location
    Centurion
    Age
    63
    Posts
    1,579
    Thanked: 538

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by Richard Mackay View Post
    What does it cost to have the PAYG facility if you don't use any electricity??
    Up to this month it would seem City power charged R339pm as per this doc. Not sure from July what the new fee is. This is for metered as well as prepaid.
    Name:  IMG_20200625_091848.jpg
Views: 213
Size:  149.1 KB

  16. #14
    Join Date
    Nov 2015
    Location
    Cape Town
    Posts
    587
    Thanked: 641

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by faniedup View Post
    Nope, the switch disconnect my Axpert from the Grid, there is no connection between them and grid. My solar system is installed as if it were a petrol generator.
    What was discussed adnausium on another forum, for a year(!) after I broke the news there a few years back of having to register your panels, is that the changeover switches where discussed in depth.

    So we all dug in, even the Victron team, trying to find solutions to overcome the constraints.
    There where none.

    IF I understand your switch correctly, you can switch the Axperts back to the grid to i.e. recharge the batts?
    Power the loads due to bad weather, no sun?

    Right?
    You switch that switch back to the grid, is the Axpert then not connected to the grid?
    Political Correctness
    Political Correctness is a doctrine, fostered by a delusional illogical minority, rabidly promoted by a unscrupulous mainstream media which holds forth the proposition that it is entirely possible to pick up a turd ... by the clean end!

    Saw this in a pub - no idea why the wife does not see it so:
    I'm not opinionated ... I'm just always right!

  17. #15
    Join Date
    Feb 2011
    Location
    Kuilsrivier
    Age
    49
    Posts
    1,959
    Thanked: 135

    Default Re: Grid-tied or off-grid. Please consider ...

    Yea, difficult question.

    The equipment you have is really great, so no problem there.

    How much more money would you be willing to spend?

    As I see it, you currently residing in Darling.
    Now Daring is not part of City of Cape Town, so you can get away with a lot more there.
    You can do a solar installation so long it follows all the NRS and SANS guidelines, but you do not need to register it with COC

    As mentioned in other threads, look for a fully compliant NRS Hybrid inverter that can be connected to a meter.
    This way you can limit your external power usage to Zero without feeding power back onto the grid.

    My starting point is always to measure existing consumption for a couple of months and then work from there.


    2007 Nissan Navara 4L Auto - Worshond


  18. The Following User Says Thank You to Wetkit For This Useful Post:

    Fvh

  19. #16
    Join Date
    Nov 2015
    Location
    Cape Town
    Posts
    587
    Thanked: 641

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by Wetkit View Post
    ... COC
    CoCT vs COC I presume?

    A CoC of the install is highly recommend for insurance purposes.
    Political Correctness
    Political Correctness is a doctrine, fostered by a delusional illogical minority, rabidly promoted by a unscrupulous mainstream media which holds forth the proposition that it is entirely possible to pick up a turd ... by the clean end!

    Saw this in a pub - no idea why the wife does not see it so:
    I'm not opinionated ... I'm just always right!

  20. #17
    Join Date
    Oct 2010
    Location
    Pretoria
    Age
    61
    Posts
    1,562
    Thanked: 522

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by the_terrible_triplett View Post
    What was discussed adnausium on another forum, for a year(!) after I broke the news there a few years back of having to register your panels, is that the changeover switches where discussed in depth.

    So we all dug in, even the Victron team, trying to find solutions to overcome the constraints.
    There where none.

    IF I understand your switch correctly, you can switch the Axperts back to the grid to i.e. recharge the batts?
    Power the loads due to bad weather, no sun?

    Right?
    You switch that switch back to the grid, is the Axpert then not connected to the grid?
    No, just as I would not switch my petrol gennie back to the grid, so my Axperts do not swith to the grid. The mains grid input to my Axperts are empty.

    There is no way my solar connects back to the grid, either from input side nor output side. Just a hard isolating switch, and it has been working like that for 18 months now, saves me between R40 and R50 a day.

  21. The Following User Says Thank You to faniedup For This Useful Post:


  22. #18
    Join Date
    Nov 2015
    Location
    Cape Town
    Posts
    587
    Thanked: 641

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by faniedup View Post
    No, just as I would not switch my petrol gennie back to the grid, so my Axperts do not swith to the grid. The mains grid input to my Axperts are empty.

    There is no way my solar connects back to the grid, either from input side nor output side. Just a hard isolating switch, and it has been working like that for 18 months now, saves me between R40 and R50 a day.
    AAAA ... Axpert charges batts only via solar. Gotcha!


    Quote Originally Posted by faniedup View Post
    To get grid backup without grid tied equipment I fitted a changeover switch. That should take care of the NRS issues.

    So now you run on your solar system, and for the odd times you need the grid you just change over, no funnies, no current transformers, no split DB.
    So you switch the entire house main DB between either Axpert or Eskom as the only feed with the changeover switch?
    Did my the penny drop now?
    Political Correctness
    Political Correctness is a doctrine, fostered by a delusional illogical minority, rabidly promoted by a unscrupulous mainstream media which holds forth the proposition that it is entirely possible to pick up a turd ... by the clean end!

    Saw this in a pub - no idea why the wife does not see it so:
    I'm not opinionated ... I'm just always right!

  23. #19
    Join Date
    Oct 2010
    Location
    Pretoria
    Age
    61
    Posts
    1,562
    Thanked: 522

    Default Re: Grid-tied or off-grid. Please consider ...

    Quote Originally Posted by the_terrible_triplett View Post
    AAAA ... Axpert charges batts only via solar. Gotcha!




    So you switch the entire house main DB between either Axpert or Eskom as the only feed with the changeover switch?
    Did my the penny drop now?
    Jip

  24. The Following User Says Thank You to faniedup For This Useful Post:


  25. #20
    Join Date
    Mar 2017
    Location
    Darling
    Posts
    108
    Thanked: 46

    Lightbulb Re: Grid-tied or off-grid. Please consider ...

    Tks to everyone for the great input

    So my answers to issues raised:

    Quote Originally Posted by the_terrible_triplett View Post
    My first reaction was:
    Is going off-grid, when you are keeping the PAYG link, a WANT or a NEED?

    Then I thought: Hold on, is this maybe a case of asking the question the other way around i.e. I bought all this, is it enough to go off-grid?


    The answer lies quite simply, in my mind, with the question you need to answer for yourself:
    When you have a Cape winter with a couple of weeks worth of non-solar-system weather over a period of a year, what is your plan to power through them?
    What will that cost you?

    And because you said, I quote "... will keep the existing prepaid as a backup ... " you need to add the cost of the monthly PAYG connection fee, to the costs incurred above.

    And you also did not lose sight of the fact that you need to recoup all the above expenditure ASAP, because solar equipment, they don't last indefinitely, nope, they don't.

    Which then begs the question to be asked:
    Why would you want to go off-grid in the first place, and not grid-tied, if you have a PAYG connection and probably paying <R2 per unit?
    Two points:
    Investment is actually lower than what it seems. I was lucky enough to be given the batteries

    Our current PAYG rate is extreme at tier 2 - R2.48 + 8% as of 1 July without considering ESKOM clawbacks.


    Quote Originally Posted by ekkekan View Post
    AFAIK the Axpert is not compliant and your one suggestion is to buy a 2nd one. They also not grid tied.

    I would rather get the Kodak that can be used as grid tied.

    You could also sell the Axpert and get a proper system configured for what you try to achieve.

    I am going to see what the market is like to sell my Axpert or ...


    Quote Originally Posted by faniedup View Post
    What I have done is basically what you have, except I'm running two Axpert in parallel.

    To get grid backup without grid tied equipment I fitted a changeover switch. That should take care of the NRS issues.

    So now you run on your solar system, and for the odd times you need the grid you just change over, no funnies, no current transformers, no split DB.
    So I have a change over switch which I currently use to charge my flooded batteries via Axpert - so not fully compliant


    Quote Originally Posted by Richard Mackay View Post
    What does it cost to have the PAYG facility if you don't use any electricity??
    Quote Originally Posted by the_terrible_triplett View Post
    In my case, R150.00 + VAT per month just to have the connection to the grid.
    Connection fees also differ between areas, towns, cities, provinces, few are less than mine, quite a few are a lot more, as some Munic's slap on even more "fees".

    I have no idea, that's why I thought I will purchase a little every month - say R100 (if possible)



    Quote Originally Posted by the_terrible_triplett View Post
    Netmetering can only be done with a Bi-directional meter, costing, in Cpt, about R 12 000+, with a contract signed between you and the Munic on the terms.
    On top of that cost, there is a +-R15 per day connection fee, in Cpt.
    Which makes netmetering not something we want to talk about.
    Agree - cannot justify that


    Quote Originally Posted by the_terrible_triplett View Post
    Adding to that, I've picked up stompies (to be confirmed) that Kodak is a Voltronic brand, a Axpert copy. Just double check that too.
    I saw that too


    Quote Originally Posted by the_terrible_triplett View Post
    Why go near solar if you can drive your Eskom usage down to <R600 (connection fee incl) per month, having spent not a cent, just pure discipline?

    Versus you drive the ROI to break even in 5 years or less ... within the warranty period of the core equipment like batts, inverters.
    And then you pray and hope it all last another 5-10 years so that you can save like mad to have the funds in cash to replace it all again.

    With grid tied you can do that faster, cheaper, than going off-grid.

    So to answer the question asked, what would I do with those panels and batts?
    I would go 5kva grid tied ... No. Feeding, Back ... and shave off every single watt I can off the Eskom bill to recoup the monies spent as soon as humanly possible.

    EDIT:
    Hold on ...

    UNLESS, without spending one more cent on big items, with the equipment as is, you can go off-grid.
    So yes, I can go off-grid for around another 10k investment (mounting kits, fuses on panels etc.)
    BUT
    it is non-negotiable to have electricity 24/7 - hence the need for access to the grid for the odd day that I cannot charge the batteries.
    btw, I also have a 5KV petrol generator, but cost to run and noise factor means it is now in the market


    Quote Originally Posted by Wetkit View Post
    Yea, difficult question.

    The equipment you have is really great, so no problem there.

    How much more money would you be willing to spend?

    As I see it, you currently residing in Darling.
    Now Daring is not part of City of Cape Town, so you can get away with a lot more there.
    You can do a solar installation so long it follows all the NRS and SANS guidelines, but you do not need to register it with COC

    As mentioned in other threads, look for a fully compliant NRS Hybrid inverter that can be connected to a meter.
    This way you can limit your external power usage to Zero without feeding power back onto the grid.

    My starting point is always to measure existing consumption for a couple of months and then work from there.
    Tks, much of how I see the situation. So we have done that and typically we consume over a thousand units per month - that excludes the aircons (non inverter type) which we do not run. All lights are LED, washing
    machines and dishwasher are mostly efficient - and we will schedule run times, way too many fridges and freezers (including camping ones), 1 x flat screen TV runs 18 hours/day, another 12, then there are DSTV decoders,
    laptops, routers, CCTV and the list is never ending - and winter is biting.
    I know you will all say become more energy wise, but with a FiL that lives in a flat on the property (paying his way) and SWAMBO loving her oven, this is difficult. [Happy wife = happy life}

    I have just purchased a Geyser Wise unit and have replaced the geyser element with a 2 KW unit.



    Quote Originally Posted by faniedup View Post
    No, just as I would not switch my petrol gennie back to the grid, so my Axperts do not swith to the grid. The mains grid input to my Axperts are empty.

    There is no way my solar connects back to the grid, either from input side nor output side. Just a hard isolating switch, and it has been working like that for 18 months now, saves me between R40 and R50 a day.
    You have given me a great idea - just have to get my head around how to keep power on 24/7 without physical connection between grid and Axpert. Based on this, for the interim I can connect everything to the Axpert and
    then take my time to decide on which route to go.

    I have another question about panel connection which I will post below

Page 1 of 2 1 2 LastLast

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •