Going Off-Grid

How much do you understand solar?

  • I don't know much about solar.

    Votes: 5 5.6%

  • I inkling of how it works, but not much else.

    Votes: 8 9.0%

  • I know what solar panels are, but don't really know how they work.

    Votes: 18 20.2%

  • I know all the details of how solar panels work.

    Votes: 41 46.1%

  • I'm currently installing solar panels at home.

    Votes: 10 11.2%

  • I already have solar and understand how it works

    Votes: 16 18.0%
  • Total voters
    89
  • Poll closed .
Im currently getting quotes on my house. Heres my logic a good system can be around 150k. What you paying for is quality of life.

Now my next question is how wise would it be to invest in the system in terms of cost? Im thinking when the electric vehicles like the ID3 hit our markets. Would it be worth while ? I travel plus minus 60km a day I could easily travel on solar alone in the future saving fuel costs or am I severely over estimating the generation capacity of the system to recharge these vehicles overnight ?

with modern Li-ion batteries you get what a 10 year warranty ?

I think if you want to be fully of the grid rather have the solar system power the plugs and switch to gas stove and oven. Might work out cheaper
 
RiaX said:
ID3
Click to expand...

General use scenario:
==============
The mid-range model has a 58 kWh battery pack. It claims to be able to do 402 km on that, but of course we know how optimistic they are, so let's work with 350 km (thus 6km / kWh). You travel 60 km on average per day, so that is roughly 10 kWh that you'll need per day for your car.

To charge that to full from empty during the night, you'll need about 3 of the 100 Ah, 48 V batteries. To charge your intermediary batteries or if you can charge the car in the day, you'll need about 5 of the 350 W solar panels*.

From flat to full:
===========
To charge that to full from empty during the night, you'll need about 13 of the 100 Ah, 48 V batteries. That is a pretty expensive battery bank just to charge the vehicle. Then you'll need solar panels to charge your 13 batteries.

If you can manage to do the charging in the day, you'll need roughly 27 of the 350 W solar panels, dedicated to charging the car*.

General:
======
Some perspective: my house (unmarried, no kids) use on average 10 kWh per day. The ID3's battery is 5 times that. So you can design a pretty cost effective system based on your general use patterns, but for a charge from empty to full you'll probably want to use Eskom.

* Assumptions have been made, e.g. 6 hours of good sun per day, no system losses, 100% charge & discharge efficiency.
 
wetkit said:
Question, why completely Off-Grid?
Is that just something you have heard?
On paper it does sounds nice, but the costs involved could be huge.
Why not rather look at a Hybrid system?
This means part of your house is on backup power, like lights and plugs.
Parts of your house still benefit from solar power, like stove, geyser and air-conditioners.
This type of system, if done correctly, does not require such a huge capital outlay, will reduce your electrical bill significantly and also offer you backup power during load-shedding.
It is a win win :D
Click to expand...
Yep costs are high. I would assume most start off as a hybrid system and see the benefit only then to slowly move off the Grid, But the majority of the cost does only come from the batteries. If lithium pricing does come down alot that would be awesome.
 
RiaX said:
gas stove and oven
Click to expand...

The energy content of LPG is roughly 12.78 kWh/kg . If you buy a 9 kg bottle, it means you get roughly 115 kWh. My last refill for a 9 kg cost me R 260, so R 2.2 / kWh. Tshwane's electricity rates in the 1-100 kWh block is R 1.95 / kWh.

The way my solar system is designed:
1. Battery charged by about 10:00 in the morning
2. 2 kW geyser switch on at 10:00. Geyser is usually finished by 11:30.

The rest of the day I then have about 2 kW capacity, mostly used for washing, dishwasher, making lunch... If I do use the oven, it is with electricity from the roof, so essentially just making more efficient use of my system.

TLDR: Don't blindly think that gas is cheaper. It is super convenient and very nice to have, but not necessarily cheaper. Sure, a larger bottle than I have will probably turn the equation, but do the math if you want to base your decision on numbers.
 
DuracellBunny said:
Yep costs are high. I would assume most start off as a hybrid system and see the benefit only then to slowly move off the Grid, But the majority of the cost does only come from the batteries. If lithium pricing does come down alot that would be awesome.
Click to expand...

The greatest problem with off-grid is cloudy/rainy days. Your design have to accept that there may be a week with minimal sun, even in e.g. Pretoria. So either overdesign like crazy, or use Eskom for cloudy days, or buy a generator to recharge your batteries on cloudydays.

*Edit: "moving off the grid" is not really a sensible goal in my opinion. I'd rather set my goal to "I want to have a cost effective and reliable power supply". The grid for me is merely a tool (with less than perfect reliability) in my system design.
 
Tacet said:
The greatest problem with off-grid is cloudy/rainy days. Your design have to accept that there may be a week with minimal sun, even in e.g. Pretoria. So either overdesign like crazy, or use Eskom for cloudy days, or buy a generator to recharge your batteries on cloudydays.

*Edit: "moving off the grid" is not really a sensible goal in my opinion. I'd rather set my goal to "I want to have a cost effective and reliable power supply". The grid for me is merely a tool (with less than perfect reliability) in my system design.
Click to expand...
Yes a very over cast day can be an huge pain. There are some exceptions that do warrant a totally off grid system and for those that can afford it.

I should off been a little more clearer in my previous post my bad:oops:. In the sense of going off grid with those that do start off Hybrid, Still do keep their Grid feed as a 3rd source of power but seeing how Eishkom is behaving with load shedding and some places power being off for days sometime. It isn't a bad idea to have a few days of battery capacity to fun you in the eventuality you don't have power for a few days. So at least then with a decent size battery bank you would be able to still be able to wait a little for the sun to charge up the batteries or even whip out the Genny or till the grid is back on. Meant off-Grid in this sense

I need to slow down a bit when replying this running all the time but what to do, batteries full is batteries full
 
Tacet said:
The energy content of LPG is roughly 12.78 kWh/kg . If you buy a 9 kg bottle, it means you get roughly 115 kWh. My last refill for a 9 kg cost me R 260, so R 2.2 / kWh. Tshwane's electricity rates in the 1-100 kWh block is R 1.95 / kWh.

The way my solar system is designed:
1. Battery charged by about 10:00 in the morning
2. 2 kW geyser switch on at 10:00. Geyser is usually finished by 11:30.

The rest of the day I then have about 2 kW capacity, mostly used for washing, dishwasher, making lunch... If I do use the oven, it is with electricity from the roof, so essentially just making more efficient use of my system.

TLDR: Don't blindly think that gas is cheaper. It is super convenient and very nice to have, but not necessarily cheaper. Sure, a larger bottle than I have will probably turn the equation, but do the math if you want to base your decision on numbers.
Click to expand...
100% my induction stove and oven is on my system (not aux) and the stove in particular is lightning fast and works like a dream
 
DuracellBunny said:
Yes a very over cast day can be an huge pain. There are some exceptions that do warrant a totally off grid system and for those that can afford it.
Click to expand...
This is my current production and its pretty much all cloud at the moment.

photo1637306221.jpeg
 
Snyper564 said:
Cloud is a dream for solar - acts like a massive light diffuser and you might clock 100+%
Click to expand...
Yep, cloud edge, I had the the effect yesterday which caused my array to trip due to the surge in amps.
 
DuracellBunny said:
Yes a very over cast day can be an huge pain. There are some exceptions that do warrant a totally off grid system and for those that can afford it.

I should off been a little more clearer in my previous post my bad:oops:. In the sense of going off grid with those that do start off Hybrid, Still do keep their Grid feed as a 3rd source of power but seeing how Eishkom is behaving with load shedding and some places power being off for days sometime. It isn't a bad idea to have a few days of battery capacity to fun you in the eventuality you don't have power for a few days. So at least then with a decent size battery bank you would be able to still be able to wait a little for the sun to charge up the batteries or even whip out the Genny or till the grid is back on. Meant off-Grid in this sense

I need to slow down a bit when replying this running all the time but what to do, batteries full is batteries full
Click to expand...

If they bring in a base line rental cost for electricity I'll consider going off-grid, but then I'll add one battery and a generator. Currently my storage capacity is enough for most days to last until about 3:00 in the morning (with aircon running). I won't make battery provision for cloudy days, but will rather get a genny for those.
 
Tacet said:
If they bring in a base line rental cost for electricity I'll consider going off-grid, but then I'll add one battery and a generator. Currently my storage capacity is enough for most days to last until about 3:00 in the morning (with aircon running). I won't make battery provision for cloudy days, but will rather get a genny for those.
Click to expand...
Im going to use the system till winter then make the call what upgrades to do - its to o soon now I need to see winter in play
 
Snyper564 said:
Just planted my first tree

View attachment 1196378
Click to expand...
1637307796875.png
Pretty happy with the production this week so far, only came on live late Monday afternoon a few teething issues on Tuesday and rain and dark clouds Wed,Thurs and today so far, yesterday lost about 2/3 hours worth of production due to the tripping array.
 
semaphore said:
View attachment 1196382
Pretty happy with the production this week so far, only came on live late Monday afternoon a few teething issues on Tuesday and rain and dark clouds Wed,Thurs and today so far.
Click to expand...
Yeah takes a bit of time to get used to - I decided just to switch eskom off and monitor as needed. Only needed to switch on twice so far. Early this month was trickle charge - now its just off :) Could likely dbl production just nothing to use it yet - eyeing more mining additions and aircons :)

1637307951194.png
 
Snyper564 said:
Yeah takes a bit of time to get used to - I decided just to switch eskom off and monitor as needed. Only needed to switch on twice so far. Early this month was trickle charge - now its just off :) Could likely dbl production just nothing to use it yet - eyeing more mining additions and aircons :)

View attachment 1196386
Click to expand...
I might need to up my batteries to turn Eskom off entirely in the evening, I have 1kw loads till around midnight then drops to around 400-500 watts constantly (marine tank).
 
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