4 hours ago, Pietpower said:

PS I think a smaller system like a 3KVA can actually have a lower ROI than a 5kVA system if your stay connected to the grid.  When you install a smaller system you remove much of the larger loads such as say a kettle or geyser or dishwasher etc.

Not necessarily, if you go the Axpert route yes, but If you buy a Victron or Goodwe you can feed in excess solar power (granted while the grid is on) to those loads, without worrying about a big load taking your system down in the event of a grid failure.

4 hours ago, PaulF007 said:

Keep in mind that you are paying now and should not need to spend any thing over the rest of the term.

But you will buy new batteries and almost certainly a replacement inverter too. I know Axperts sometimes last quite a long time, but the odds of replacing one in the 5-10 years bracket can't be that low.

3 hours ago, PJJ said:

without worrying about a big load taking your system down

Yup, that's one of the things I realised very early on. The majority of your loads are below 1kw. The big consumers often use less than 1kw, but run for long periods. Fridges and Freezers especially. The cheapies have a 250W compressor and can run 12 hours out of 24 (especially as they age and the seals start to go). That means you can offset way more than 50% of your consumption using a very small inverter, I think I calculated that my 1600VA unit (since upgraded) could offset 75% of mine. But this only works if you have a true hybrid that can draw the rest from the grid. Without that, you need the big inverter to cover the peak, the big battery to supply the peak, etc etc.

12 hours ago, plonkster said:

The big consumers often use less than 1kw, but run for long periods. Fridges and Freezers especially. The cheapies have a 250W compressor and can run 12 hours out of 24

Very true, if I look at my house consumption 80% of the time its below 500W, with only peaks when things like the Geyser and Stove start chugging away, that's probably why I was able to get away with a single 800VA Multi for so long.

My problem however was if both the fridge and chest freezer compressor both came on at exactly the same time I would trip the little Multi (It only happened like twice, both times after they were left disconnected for a while and reconnected back at exactly the same time) those compressors have insane startup current.

But since I have the second 800VA unit on the wall its never been a problem since.I can also now for the first time ever use my pressure pump when the grid is down, its a 0.85KW pump.

At first I wondered whether it would be worth it to add the second Multi, but when loadshedding started again and I had to forgo a few showers the decision was easy. 

 

 

16 hours ago, PaulF007 said:

Lett say current Eskom rate is R 2.50 per unit - R 1 125/2.5 = 450 unis

This is very variable. In Johannesburg you would not pay that much as a residential consumer, even if you used a lot. Interestingly Eskom, for some reason, tweeted their residential tariffs last night, and COJ residents pay less than those who have the pleasure of dealing directly with Eskom. 

I'm pretty sure that COJ charges less than COCT as well. That said, COJ's infrastructure is not the most modern. 

Anyhow, the calculation varies across municipalities and one should check the VAT inclusive tariff before doing the sums. 

Also factor in increases. 10% PA is not unreasonable. 

Have a look at this

It was discussed at length back in 2016 , I wonder how much of the predictions came true

On 2015/06/29 at 9:04 AM, Dope said:

I am planning on going solar, but I don't know if it will be worth it in my case, as our monthly electricity usage is around 400kWh. Will it be worth the expense of getting a solar geyser and some PV panels, batteries and inverter?

 

I had a look at prices and they look like this:

Inverter - R 9000

Solar Geyser - R4000

Some solar panels - R 7000

4 Deep cycle batteries - R8000

 

I can do most of the install myself as my dad is a plumber and my brother an engineer, so I can get them to do most of the work for me

I know this is a old post, but when reading this question I would answer yes to the solar geyser but the inverter,  batteties and panels will be difficult to justify just yet. R4000 is probably a low pressure geyser that I don’t have experience with but if it can deliver the hot water at acceptable temperature and pressure, it would be able to save close to half of the current 400KWH usage a month which in my area would be R2.17 / KWH incl of vat.

So 200KWH x R2.17 = R434/month saving

The fact that he can do most of the installation himself is a big bonus, I done my own high pressure 200.Ltr. ev tube geyser last year for about R13000. 

So even if the geyser cost him R13000. / R434 = 29.95 month pay back. Once it’s payed take the R434 saving and spend it on pv solar (Start small just to cope with load shedding)

On my own DIY it has cost just under R50K for my 200ltr geyser and a 5KVA Axpert installation and I am about 80% off-grid only if my family would switch things off after use, I would be 100% off grid. My payback should be about 4 to 5 years.

My total usage is in the range of 700KWH a month, but since my solar installation I only buy about 200KWH pre-paid a month. In my opinion it is worth considering DIY for any person who is prepared to work with tools and who is prepared to do lots of learning and reading and follow strict advice from a licensed electrician🧐

I just got a 7.8kw solar array installed on my roof (live in Virginia). I got a company, PEG Solar, to take care of everything. The total project cost (panels, inverter, installation, meter, EV Charger etc) before tax credits and incentives was $21,000. Over the past week it has generated about 12kwh per day, which is just a little less than what you would need to offset your electric costs, so if I were you, I'd be looking at a 8-9 kw system if you want to be 100% renewable.

1 hour ago, Caela said:

$21,000

This is something that I've picked up on recently. I'd watch American shows on home makeovers (used to love Mike Holmes's show) and afterwards they'd come up with the total cost and I'd quickly multiply that by 15 mentally (cause that's the exchange rate to ZAR) and almost always find that I could probably rebuild the whole house (with bricks... none of that wooden framing and nonsense) for about the same price. The point being that in America you seem to pay a lot more for your stuff, except that salaries quite likely also scales proportionally to the cost of things.

(Same is true for Europe btw... bigger salary... higher rent... works out about the same in the end).

So, 21k... that's like 300k in ZAR. You can install one MOTHER of a system for that money 🙂

Edited March 8, 20206 yr by plonkster

11 hours ago, PJJ said:

But since I have the second 800VA unit on the wall its never been a problem since.I can also now for the first time ever use my pressure pump when the grid is down, its a 0.85KW pump.

Your two 800VA units make up the 1600VA I used to have. I ran an 850W well point pump on that, two pressure pumps of 450W each, fridge, freezer, and of course the usual essentials (lights, internet, TV... 🙂). It is more than adequate... EXCEPT... as I've said a few times, you miss the ability to run the microwave oven. You don't realise the convenience of that appliance until you want to make a sandwich and the butter is hard, or when you have a hungry infant who's just gone onto solids and needs two tablespoons of mildy warm pumpkin and beans.

9 hours ago, Caela said:

I just got a 7.8kw solar array installed on my roof (live in Virginia). I got a company, PEG Solar, to take care of everything. The total project cost (panels, inverter, installation, meter, EV Charger etc) before tax credits and incentives was $21,000. Over the past week it has generated about 12kwh per day, which is just a little less than what you would need to offset your electric costs, so if I were you, I'd be looking at a 8-9 kw system if you want to be 100% renewable.

From a 3.8kW solar array we get more than 15kWh per day summer and winter.  More sunshine around here it seems.

11 hours ago, plonkster said:

I could probably rebuild the whole house (with bricks... none of that wooden framing and nonsense)

Apologies for derailing the thread a bit, but in the south and middle parts of the US, they don't build houses with wood (instead of brick) to cut costs, but for Tornado safety-concerns, as far as I remember (or it started out that way).

 

Nope, turns out to be an old wive's-tale.

 

-G-

Edited March 9, 20206 yr by gallderhen

39 minutes ago, gallderhen said:

Nope, turns out to be an old wive's-tale.

There are probably many reasons, but I think the weather is the main one. A large old brick house built our way would be horribly cold over there. I would also expect large differences between how you build a house in Florida vs how you'd build one in Minesota. Both places that I have never been, I just know the one has tropically hot weather and the other freezes over every winter 🙂 Still, prices seem off by a factor of 2 (it seems). Which probably just underscores again that you can't really think in another currency when determining what something is worth, you have to think "percentage of my annual income" or "how many Big macs?" or "how many cans of Coke-a-cola", or the one my father used: How many liters of Diesel for each head of cattle delivered to the market 🙂

32 minutes ago, plonkster said:

There are probably many reasons, but I think the weather is the main one. A large old brick house built our way would be horribly cold over there. I would also expect large differences between how you build a house in Florida vs how you'd build one in Minesota. Both places that I have never been, I just know the one has tropically hot weather and the other freezes over every winter 🙂 

Been following some of the USA building details and how they build is very interesting. 

One of the major differences between SA homes and USA homes is insulation combined with sealing.  Their building envelope is just much more energy efficient. (30-80 times)