Planning to go off grid on electricity - Page 3





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  1. #41
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by faniedup View Post
    My house consumes 30kWh per day often. Run a pool pump, borehole, fridges, oven, iron, dishwasher and geyser all at some time during the day and it all adds up quickly.

    I have made peace with the 20 to 25kWh I save per day if not cloudy, and still have reserve left for loadshedding in the dark of night.

    After nine at night it goes back to grid, not worth the while to chase the tail end. If grid goes belly up I'm off grid with some lifestyle adjustments.

    Exactly. The point is to size a system that you can get through 100% of the days, without any compromise in use, gets pretty expensive.

    I was a doctors home last night. Fully off grid. The guy has something like 15 kW of panels, I big stack of batteries and they can get through rainy days on batteries alone.

    This is already a 2 years old installation so I can hardly see the that dropped a cent less than R 250 000 on that build.

    Ahem.... His installer told him 3 years payback... I have seen his use yesterday. 50 kWh for the day. Nope. He won't pay it back in 3 years. Not even close.


    My build happens because I have multiple things making it worth it at this time.

    1. I get my equipment at dealers prices and subtract the VAT.
    2. I had to replace my geyser anyway. Insurance paid for it and I decided instead of going direct solar geyser again I go PV. So in my case, I could buy more kW in panels that what I need for the geyser.
    3. I have a solar tracker frame.
    4. I do my own installation.
    Last edited by biltong; 2020/09/29 at 02:11 AM.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  2. #42
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by ekkekan View Post
    If we look at the true results with tracking at the CSIR we see that you can get more than a 40% increase with dual tracking. If we apply the regular 6kWh/kW installed that Faniedup gets we can get to over 8.4kWh/kW installed.

    Attachment 590390

    This graph is not very accurate. It does not reflect the extra hours you get from tracking - which is where a significant portion of the extra come from.


    From our simulations, (both with the fancy paid for simulators and our own excell derived version), at my local position I will get an annual average of about 1700 kWh/kW for a well oriented fixed array, 2500 kWh/kW for a single Est/West tracker and 2900 kWh/kW for a dual tracking system.

    We are currently babysitting eight dual tracker systems of 14 kW each, where data is logged every 5 minutes for each panel, and the simulations gets very close.


    Now, from a technical point of view my system is designed to push minimal limits.

    On average for the setup I have calculated, I can get an average of about 27 kWh per day over a year.

    However, the advantage in our neck of the woods is that we sit with either almost clear skies, or rainy days. This means that on most days I will just over 30 kWh for the day - which is where my budget comes from.

    The only way to make this work, is to have virtually no losses in particular on storage - and the system is sized to exploit the very feature to see if the Kilowatt Labs unit can deliver on that, and to see how practical the geyser works to gobble up every last waste one has.

    Secondly, the kids will have to learn not to camp out in the shower.

    As said. On a rainy day, I will have only a sniff of power. On those days, there will be no option but to run a small gennie or be even more dependent on gas.


    I don't say it would not be awesome to put in the double sized array and a 50 kWh battery bank to get me through everything. But I don't have that budget.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

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  4. #43
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by biltong View Post
    I don't say it would not be awesome to put in the double sized array and a 50 kWh battery bank to get me through everything. But I don't have that budget.
    This subject matter has been discussed in depth on another forum in the past.
    I have one question: What would the array cost to build, maintain?
    Versus not building said array and using that "saving" and add a couple more panels?



    Quote Originally Posted by biltong View Post
    ... dropped a cent less than R 250 000 on that build.

    Ahem.... His installer told him 3 years payback... I have seen his use yesterday. 50 kWh for the day. Nope. He won't pay it back in 3 years. Not even close.
    R 250 000 / 36 months = R 6 944 savings on Eskom per month to break even after 3 years.
    Question is: Did it cost them before solar, +-R7k on Eskom, and they are now saving that?

    In my book the sum for ROI is simple: Total cost of the install divided by the savings made on Eskom bill = payback period.


    There are 3 types of installs:
    1) Needs - you make it work with the least amount of money, and smile all the way.
    2) Wants - you want it so you spend it - wife catches on fast.
    3) Solar Hobby - no price tag on a hobby. ��
    Last edited by the_terrible_triplett; 2020/09/29 at 08:21 AM.
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  5. #44
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by the_terrible_triplett View Post
    R 250 000 / 36 months = R 6 944 savings on Eskom per month to break even after 3 years.
    Question is: Did it cost them before solar, +-R7k on Eskom, and they are now saving that?
    It is irrelevant what it was before.

    R 7000 per month means at our current tariffs he needs to use 116 kWh per day every single day - and he does not.

    With 15 kW fixed panels, he can harvest on average only 75 kWh per day.

    His cost went into batteries to get him though the lean days.

    And for that convenience, you can't get something that pays for itself.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  6. #45
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by the_terrible_triplett View Post
    This subject matter has been discussed in depth on another forum in the past.
    I have one question: What would the array cost to build, maintain?
    Versus not building said array and using that "saving" and add a couple more panels?
    I am not sure I understand you correctly.

    If you mean array in terms of batteries, then the problem simply is that on rainy days you can't enough panels to pull you through.

    You absolutely need storage.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  7. #46
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by biltong View Post
    I can tell you one thing. No more air conditioning in this house for a while....

    In order to make this, I will have to change my oven to gas and I will need some gas backup for the geyser on bad days.

    My biggest challenge will be how to get from dusk to dawn with 3.5 kWh. That will take some work.

    Some things like the water cooler and chest freezer will probably have to run timers.

    I have no illusions that this will require some change in our domestic ways.
    Just the opposite in fact.

    Make hay while the sun shines. When you have power spare, and you will have, run the aircons, hot or cold galore. Better than throwing the energy away.

    Never put in expensive infrastructure to replace Eskom when it does what it does best. Produce power at night.

    There is no cheaper power than Eskom power at night. Your system should be to carry you when there is no Eskom and to make hay when the sun shines.

    When there is Eskom and it's dark - use Eskom.
    Cheers

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  9. #47
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by Fluffy View Post
    Just the opposite in fact.

    Make hay while the sun shines. When you have power spare, and you will have, run the aircons, hot or cold galore. Better than throwing the energy away.

    Never put in expensive infrastructure to replace Eskom when it does what it does best. Produce power at night.

    There is no cheaper power than Eskom power at night. Your system should be to carry you when there is no Eskom and to make hay when the sun shines.

    When there is Eskom and it's dark - use Eskom.

    I agree there is nothing cheaper than Eskom at night.

    In my case, AC load will be transferred to the geyser.

    My problem for the moment is that we first need to shift load to the day to make that hay. At the moment I am running the grid tie with 1.6 kW panels losing units.

    At least the battery will give me solid backup power during the day for load rolling to run lights and computers.

    The inverter I have in mind at is a full house option that can utilise mixed inputs, so I can easily use Eskom as input instead of a gennie.
    Last edited by biltong; 2020/09/29 at 10:01 AM.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

  10. #48
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by biltong View Post
    I am not sure I understand you correctly.

    If you mean array in terms of batteries, then the problem simply is that on rainy days you can't enough panels to pull you through.

    You absolutely need storage.
    Sorry, unclear on my side. The solar tracking array, not the panels.

    We worked out on another forum that it is a lot more expensive to have the array tracking the sun than adding a couple more panels. Even with multiple MPPT's and N, E, W facing arrays, the cost was still cheaper than having one array track the sun ito the cost of the install, the frames, the concrete base, the maintenance ... all of it.

    And the the motors, the gears, host of more parts needed compared to a larger fixed array.

    If there is space, some guys had a ground mounted array that they manually adjust for the 4 seasons. That was quite cheap and effective idea too.
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    Saw this in a pub - no idea why the wife does not see it so:
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  12. #49
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by the_terrible_triplett View Post
    Sorry, unclear on my side. The solar tracking array, not the panels.

    We worked out on another forum that it is a lot more expensive to have the array tracking the sun than adding a couple more panels. Even with multiple MPPT's and N, E, W facing arrays, the cost was still cheaper than having one array track the sun ito the cost of the install, the frames, the concrete base, the maintenance ... all of it.

    And the the motors, the gears, host of more parts needed compared to a larger fixed array.

    If there is space, some guys had a ground mounted array that they manually adjust for the 4 seasons. That was quite cheap and effective idea too.

    It all depends. I have a small light frame tracker that will be able to take 3 panels - so it seems I can fit 435W panels on there which will give me the 1.2 kW.

    This frame is on the ground, and I anchor it with cables. No bases needed.

    Since I have it mahala, I will use it.

    But a 4.5 kW tracker... That is already a beefy frame with a base. No. I wont go that way for anything other than because I can.


    But as said, I think my circumstances are a little unique, and not everyone can expect to have all this.
    1999 Discovery 1, 300 Tdi - "Tink Tanky"
    2004 Discovery 2 Td5 - "Blink Tanky"

    "Logic is a systematic method of coming to the wrong conclusion with confidence."

    "A technician will let a system degenerate to the level of his understanding and maintain it there."

    "...it is abundantly clear that you are an arrogant C-nut." - Estee. (I was overwhelmed. It was the nicest thing someone has said to me in a week!)

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  14. #50
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by faniedup View Post
    My house consumes 30kWh per day often. Run a pool pump, borehole, fridges, oven, iron, dishwasher and geyser all at some time during the day and it all adds up quickly.

    I have made peace with the 20 to 25kWh I save per day if not cloudy, and still have reserve left for loadshedding in the dark of night.

    After nine at night it goes back to grid, not worth the while to chase the tail end. If grid goes belly up I'm off grid with some lifestyle adjustments.
    Are your panels fixed or tracking?
    Padraic Berry

  15. #51
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by NewLandy View Post
    Are your panels fixed or tracking?
    Fixed, facing north @30deg angle

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  17. #52
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by faniedup View Post
    Fixed, facing north @30deg angle
    You're yields are the benchmark I'm using for fine tuning purpose...
    Padraic Berry

  18. #53
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by biltong View Post
    ...... Secondly, the kids will have to learn not to camp out in the shower.....
    .....and that is the crux of the matter, getting your family educated/trained.

    Sorry, I little bit off track, but....

    Nine months off grid, came home yesterday at 17:00 and the dishwasher is running. On top of that my son did some trouble shooting, because the one JoJo tank did not want to fill. He opened a valve that was closed. By doing this the pressure pump (0.37kW) circulated the water the whole night through the tank...out and in.

    My base load is 600W/h through the night (a little but more up to 21:00). Only got the batteries up to 80% yesterday due to the weather. Needless to say, we had our own inflicted load shedding at 05:00 this morning.
    Last edited by LdLL; 2020/10/03 at 12:20 PM.

  19. #54
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    Default Re: Planning to go off grid on electricity

    Quote Originally Posted by LdLL View Post
    .....and that is the crux of the matter, getting your family educated/trained.

    Sorry, I little bit off track, but....

    Nine months off grid, came home yesterday at 17:00 and the dishwasher is running. On top of that my son did some trouble shooting, because the one JoJo tank did not want to fill. He opened a valve that was closed. By doing this the pressure pump (0.37kW) circulated the water the whole night through the tank...out and in.

    My base load is 600W/h through the night (a little but more up to 21:00). Only got the batteries up to 80% yesterday due to the weather. Needless to say, we had our own inflicted load shedding at 05:00 this morning.
    Put a timer on the dishwasher plug. Only operational from**h00 to **h00
    Robert van den Berg

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    Default Re: Planning to go off grid on electricity

    Biltong,
    Welcome to the club - Kilowatt Labs club. I know the old batteries (lithium) has developed over time and the capacitor idea puts most people off. Let them cling to the olden days technology. My supercap is working absolutely 100% and is completely maintenance free. It will last very long and functions very well in conditions below zero degrees and up to very hot summer temperatures.

    Enjoy your system - and remember that you can phase in the panels and batteries over time as experience will guide you. I enjoy the safety of lights and perimeter fence being alive while the others are in darkness. Having to work from home with guaranteed internet and power to electronics ( including the welder) is such a blessing. The saving on power is in my case a added benefit.
    [SIGPIC]
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  21. #56
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    Default Re: Planning to go off grid on electricity

    Nou sit 'n bietjie fotos op van jou installasie.

    My neighbour is also very interested in the supercap approach.
    Quote Originally Posted by Groen bloed View Post
    Biltong,
    Welcome to the club - Kilowatt Labs club. I know the old batteries (lithium) has developed over time and the capacitor idea puts most people off. Let them cling to the olden days technology. My supercap is working absolutely 100% and is completely maintenance free. It will last very long and functions very well in conditions below zero degrees and up to very hot summer temperatures.

    Enjoy your system - and remember that you can phase in the panels and batteries over time as experience will guide you. I enjoy the safety of lights and perimeter fence being alive while the others are in darkness. Having to work from home with guaranteed internet and power to electronics ( including the welder) is such a blessing. The saving on power is in my case a added benefit.

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