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Shall we start cleaning up this thread and do as we suggested, a one stop place to get info on all solar parts, that even the most newest newbie can get a grip on it all?

@Energy can you get the parts available for ordering if we get it all down pat?

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Reducing consumption of electricity by changing to gas cooking makes no sense unless we're looking at 100% off-grid set-up with no Eskom supply. Firstly, you incur capital expenditure setting it all u

They are there to protect the cable and limit the possibility of a fire. I have a solar fuse on each string (12A). If you have a short on one of your strings it will "draw current from the remaining s

Some of the most important things to keep in mind when selecting fuses to be used for PV lines and in line with the batteries - taken from http://www.littelfuse.com/~/media/electronics/product_catalog

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Right, I was told that CoCT has more solar radiation than Pretoria ... I laughed, till I was not. 

Turns out CoCT has 2300 - 2400 kWh/m2 per annum. Pretoria has 2100 - 2200kWh/m2 per annum.

Upington ~ 3 100 kWh/m2 per annum. Nearly 50% more than say Pretoria.

See here: http://www.sauran.net/

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1 hour ago, The Terrible Triplett said:

Right, I was told that CoCT has more solar radiation than Pretoria ... I laughed, till I was not. 

Turns out CoCT has 2300 - 2400 kWh/m2 per annum. Pretoria has 2100 - 2200kWh/m2 per annum.

Upington ~ 3 100 kWh/m2 per annum. Nearly 50% more than say Pretoria.

See here: http://www.sauran.net/

I can't help but 🤣 at this statement.

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  • 1 month later...

So I did an attempt to calculate the possible production for 10 330W panels at my house in Cape Town.

I started with solar insolation stats from the site - http://solarelectricityhandbook.com/solar-calculator.html

I then factored in the angle of my panels, the efficiency of the various steps and came up with this:

https://docs.google.com/spreadsheets/d/1LyiPxAJl0FcZ7htSgYBEwErdAKaaLO1zrc2gkk1EnOI/edit?usp=sharing

image.thumb.png.8956f24f9e4d462ccad1d5f4ccd1b5da.png

How does this look compared to practical experience?

The power factor I guess is a big thing in terms of the power - I used 0.6 which is pessimistic but I saw somewhere that is a figure that is used.

If these numbers are right then the real challenge is to use all that you generate at the times it is available?

Regards,
Elbow

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  • 1 month later...

... @TTT

hmm, can't find your newest spread sheet.

Does it contain the AmeriSolar 330Watt panels.

Trying to quickly determine what a 9 panel array, configured 3S3P will produce and if it makes sense to go with smaller MPPT or not, considering i was to go 3S4P or even 3S5P if I got space.

G

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5 minutes ago, georgelza said:

... this is the option (brand) my installer has, and what my bank account will ok.

I hear you, having been there myself, I feel you.

It bit me in the arse, what my supplier had and what I could afford. Hope it is not the case with you,.

Had 200w and 310w panels for years, 2 x MPPT's and all that, till I got gatvol, dug in, sold it all and went Canadian and grid tied. Sorted. 🙂 

 

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  • 2 weeks later...

jislaaik this is very mind boggeling.

My monthly consump. is 750kwh

25kwh/day. with all the addons what do I need to run off grid say 2 days with out sun worst case.

would appreciate very mutch.

I see 1 firm talks about base line of 1.3 kw, what does that mean. 

 

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2 minutes ago, Tokkiebod said:

25kwh/day. with all the addons what do I need to run off grid say 2 days with out sun worst case.

Without sun... well that's simple arithmetic, you'll need 50kwh storage. For LFP batteries that will set you back around 350k ZAR.

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1 hour ago, Tokkiebod said:

I see 1 firm talks about base line of 1.3 kw, what does that mean. 

Baseline, if he means baseload, think of it as the power used automatically in the background all the time, even when you are asleep or away. Fridges, alarms, geyser, fishtanks, night lights, that sort of thing.

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2 hours ago, plonkster said:

Without sun... well that's simple arithmetic, you'll need 50kwh storage. For LFP batteries that will set you back around 350k ZAR.

well if i cut the sunpart backup out what wil i need? may by backup generator.

like how many pvs, Li_ion batteries and inverter

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3 hours ago, Tokkiebod said:

like how many pvs, Li_ion batteries and inverter

Tokkiebod, to answer the question is a huge effort ito working it all out, only for the result to change, when the load is reduced.

Start with how you can reduce the 25kwh/day ... then it becomes easier AND more affordable.

OR is the 25kwh/day non-negotiable?

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4 hours ago, Tokkiebod said:

like how many pvs, Li_ion batteries and inverter

Well my consumption has been 25kwh per day or so.

I have 3.1kw of panels, 3kw inverter, 4.8kwh of batteries.

Once its dialled I estimate I can reduce my grid usage by half.  How well it comes out boils down to moving usage from evening to day.

My batteries only power my essential loads - about 300-40-W worth. That lasts maybe 10 or 12 hours depending on how far I discharge the batteries.

So I’m definitely not off-grid.  To do this I think I would need:

Reduce demand:

  • Water heating to solar thermal
  • clean up some remaining halogen bulbs etc
  • Cooking all to gas
  • remove pool / eliminate pool pump 

Those steps might halve my demand and get rid of the high load items.

Up generation capacity: I think then I’d need substantially more panels - twice as many maybe?

Much more storage: And definitely much more batteries to make sure I have a day’s autonomy.

And a generator when the sun just won’t come out.

Obviously that would certainly double my spend.

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the terible triplet (dont knowhow to bringup your name) 25kw is nogabile. As you said its difficult to calculate and I dont understand the calculations and its also difficult to express myself. Thats why I asked the experts. 

I just want a ball park figure to see if I can afford it. At this stage there is no Eskom power and no house yet. So this will be new installation from scratch.

I want to see if I can  aVoid to pay ESKOM upfront to provide the electr. to the farm. 

Edited by Tokkiebod
forgot to mention something
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11 minutes ago, Tokkiebod said:

the terible triplet (dont knowhow to bringup your name) 25kw is nogabile. As you said its difficult to calculate and I dont understand the calculations and its also difficult to express myself. Thats why I asked the experts. 

I just want a ball park figure to see if I can afford it. At this stage there is no Eskom power and no house yet. So this will be new installation from scratch.

I want to see if I can  aVoid to pay ESKOM upfront to provide the electr. to the farm. 

You quote someone by typing the @ sign and then the first 3 letters of their nic. 

 

A 25Kw off grid system with battery backup could cost in the region of about  R400k, or even more. How did you get to the 25Kwh daily usage? Do you really need to use that much at night as well? If you can cut down on your night time usage, the cost will come down. 

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2 hours ago, Tokkiebod said:

ball park figure

Well, let's go with the 25kWh a day. To generate that much you'll need 5kWp of PV. Probably better to go with 6kWp. At around R6/watt (you can do better, but let's err on the high side), so that's 36k ZAR, let's say 35k (I like round numbers).

You got to store that somewhere. Let's say you use a Diesel generator if there is no sun and you need to store only one day's worth. That's 25kWh storage. LFP storage is around 7.5k per kwh, so that's around 180k off the top of my head (too lazy to drag out a calculator).

So we're around the 200k mark and we still have to buy an inverter. You're not going to use a small 3KVA, you're going to look at a 5KVA and larger. Let's say you go with a 5KVA Multiplus, that's around 28k vat inc.

Now you need solar chargers. 6kw at 48V, let's say 50 to make the math easy, that's 120A. So you're probably looking at 2 x BlueSolar 150/70, 15k for the two.

So the total is around 260k and we still have to buy cables, materials, and install the thing. Let's just call it 300k round.

As you can see, the battery storage component is more than half of your total cost. If you can drop that by half, you can lower the total cost by a third.

So adding on to Silver's estimate, you're looking at a ballpark between 200k and 400k.

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Reducing consumption of electricity by changing to gas cooking makes no sense unless we're looking at 100% off-grid set-up with no Eskom supply. Firstly, you incur capital expenditure setting it all up, secondly, you will merely move the expense of electricity over to purchasing of gas, thirdly, you are now at the whims of gas supply and travelling around to get it plus over time it is likely to go up in price and lastly you will continue to contribute CO2. Unless you enjoy cooking on gas or already have a gas stove, I would not change, rather spend a little more on the PV system.

 

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