I think both approaches are valid. I personally decided to spend the money on good equipment and go cheap and cheerful on the batteries. I learned that you can go a LONG way on second-hand batteries (though it requires buying a set almost yearly :-) ). Unfortunately the rest of the world also learned that... :-)

Thinking back to my parents' solar system, they did it the other way round. The good sine wave inverter came several years later, the batteries came on day one.

As long as you have a plan. I'm actually glad I did it this way round. If I didn't, I'd likely aim for off-grid rather than the hybrid self-consumption I'm going for now. That would have been a mistake. At least, I THINK it would have been a mistake :-)

That basically sums Solar power/design up between the last two posts. At the end of the day it is your cash that you are going to spend and if it goes wrong .. again your hard earned money that will be gone. .. 

Whether the rest has an opinion or not.

That basically sums Solar power/design up between the last two posts. At the end of the day it is your cash that you are going to spend and if it goes wrong .. again your hard earned money that will be gone. .. 

Whether the rest has an opinion or not.

Amen to that.

Sent from my SM-N900 using Tapatalk

Ok, just reminds me that there are multiple approaches to systems, similar to investments. There is money to be spent, and if you think you are going to get your investment back soon, then you are in the wrong game, for the wrong reasons.

I understand the alternate approach, but I feel it is from users who have a lot of time to hunt down the batteries, have a bit of cash on hand, aren't on Utility, or this is a dedicated pursuit. However, my approach is rather towards the Joe Blogs, or the new, or those with jobs outside the industry who are just feeling their way....

My experience so far has taught me that unless you are absolutely dedicated to the "cause" you will be sadly disappointed in the results (the cost pricing is way too high still), and to mitigate you need to invest in storage capacity (AKA batteries) first. If you have the time to fiddle, and turn this into a permanent hobby, then by sure, take the approach mentioned above, and use your gained knowledge to get the maximum out of your system... The average Joe/Home User does not have the patience or time to "fiddle", they are looking to mitigate power failures or stop paying their municipality... So batteries first is the better approach for them (they have other jobs and hobbies, solar should not be a huge chore).

 As a "do over" on my small system, I would have definitely spent the small fortune on batteries (R40k on batteries only) rather than go through the headaches and nearly R75k have had to spend already and still am sitting with under-capacity on a 4/5K Axpert...

I will stick in my corner for now and mumble "batteries, batteries, batteries"...

22 hours ago, KLEVA said:

Yes, we headed off topic, but the principles were kept... When you know how to drive you can afford to drive a Merc/BMW... But when you start out you are most likely driving a second hand beat-up claptrap where your feet act as better brakes through the floorboard rust than the actual brakes on the car!

The Axpert has it's many annoyances, but as a starter solar system it seemed (In my Opinion) to have a much smaller starting perspective cost wise, and a simpler installation. They also seemed pretty decent at handling the wife's abuse, and can still be parallel connected later to expand, at a much smaller cost than the "better" kit.

You do have to remember though, that you are buying a Tata/Lada equivilent, rather than a Merc/BMW. Decent enough to do the job, but requires a bit more attention and hands-on. I have been quite Ok with mine, even with its faults, but those faults would have been unacceptable if I had spent 3 or 4 times the money.

All that aside, the original point of this post was about how to access the input (solar) kW vs Batteries... Go back to one of my Blogs, and you will see that no matter the system (within reason), no matter the panels (within reason), the BATTERIES are the key... Solar power needs to store, and it needs to store for the longest time at the best possible power output... Spend your dosh on Batteries first (and it is expensive to do it right first time, even more expensive if you have to do it right the second or third time after a mistake).

A high capacity storage system can enable you to go off grid, even if you have a TATA, but if you skimp there, then you may only have 1 or 2 hours off-grid when the Sun disappears, no matter how much you feed back to Eksdom/Eishtekwini... If they dead, you will be too.

One of my most reliable systems (even better than my entire house supply) is a 10W solar panel (yes, you read that value right), feeding a massive 102Ah Deep Cycle through a cheap Ellies charger... The draw on the battery per day is incredibly low (admittedly), but I once tried to replace it with a basic 40Ah deep cycle of the same brand and the whole setup collapsed in a few days of no sun... Despite the recommended values for charging currents and the negatives, this is the system that has been feeding my alarm/gates/electric fence/intercom/solar pump for nearly 2 years without amendment (should get a slightly bigger solar panel - like 50-100W according to EVERYONE, but the battery stays fully charged, so haven't messed with it yet in 2 years).

So, my rule (after lessons learned) is batteries, batteries, batteries - The best, the most powerful, and as many as you can afford.

Again, this is my personal experience and there will be other perceptions and answers, from even more experienced members. But I am a firm believer in the idea that something even as basic (and reasonably reliable) as an Axpert with a Bentley/Ferrari battery bank, will give a better system than a Victron/Blue/etc system with a crap battery bank. So if your budget is limited, point your money at batteries first, and get the best you can.

My 2c over.

Interestingly I used to have the exact solar system running our gate motor, garage motor and 2x 10W flood lights - it worked very well for many years more than what they battery should have lased. Only difference: I had to upgrade to a 50W panel (the cost between 10W -> 20W and 10W -> 50W was marginal) due to a tree, in winter which shaded the panel till about 11am. The wires was already in place and I was too lazy to run new wires to a different spot, on a different roof. I used a cheap (R110?) 10A PWM charger (still have it. still use it to charge car batteries) . A couple years ago when I put up a big solar system, that same panel and charge controller was installed at my mother's place. 

1 hour ago, KLEVA said:

As a "do over" on my small system, ...

To be honest, after my first mishap in batteries I felt the same. Get the right batteries, not negotiable.

Today, on my 4th set over 6 years having bought the wrong batts it is not worth it in cities with Eskom. Batteries are only worth it if you are off grid and have to rely on a generator.

Joke is at one stage I used 2 x 105ah old maintenance free batts just to connect the panels to the inverter, as I was wanting to use solar, not batteries. Did that until the power failures returned. We work from home. Now I have 4 x T105RE's, which is more than enough for any power failure. Outside failures they never go below 80-85% SOC, have to use them right. And they have never seen Eskom for charging, none of my batts have. NOTE: To use a very small bank, depending on the charger settings, can damage the batts.

Truth be told, I don't really need them as there are no power failures.  Will go back to 2 x 105 old batts any day.

 

PS. 2 x 10w on for 12 hours per day = 0.54c per day = R16.74 per month = R 201 pa. Want to half it, get 5w bulbs with exceptional lumens. 

So I took my 105ah batt, controller, panel and 2 x 12v lights and sold it all. Lights back on Eskom with 220v 10w lights cheaper to replace. 
Was fun though.

2 hours ago, KLEVA said:

I would have definitely spent the small fortune on batteries

Actually, I would agree that that might have been the better long term approach, but hindsight is an interesting thing. You forget all about the constraints you were working with. Once you consider the constraints, you have to admit that you'd probably do the same thing again.

In my case, I had a new baby inbound, we had to install another geyser in the house because the solar one wasn't keeping up in winter (and not enough roof space for more), and I was very worried about the effects of load shedding on my little from-home free-lancing gig. I canceled a particular insurance product around the same time, in favour of something cheaper, and that particular product had a cash payout component. I decided to use that for a solar setup, so that essentially left me with around 25k (!) to make a start with. This was in 2013, so the ZAR/$ was below 10, the ZAR/EUR was between 11 and 12 (and old stock was running out fast with new prices looming). So there you have the first two constraints: Money, and some kind of urgency related to the load shedding and exchange rates.

There was no Axpert. Apparently some people were trialling them elsewhere in the country, so the first single units were here already, but I only heard about that last week. The choice was between Cotek, Meanwell, Victron, or something clearly from China (Doxin came up a few times, saw people who bought them).

Then I saw MJ Lorton's videos on youtube. He was still based in Cape Town back then. That was the end of the inverter question. I wanted a Victron Multiplus! Only problem was, I'd have to blow half my budget just on the inverter!

Not a problem I thought, the inverter is one of the most expensive components, everybody knows that! You don't want to buy an inverter twice.

Next up, the charge controller. Microcare makes an LED model and it is quite affordable. I'll go for that one. I was quickly talked out of that proposition when it was pointed out that this little controller had a Maximum open circuit voltage of just 50V. So I ended up with a charge controller three times more expensive.

It was as clear as daylight to me that I don't want to go with cheaper equipment.

So now I had less than 10k left, and still needed to buy cabling and all that stuff. That would mean skimping on the batteries. Given the cost constraint, it was literally a choice between a cheap inverter and a cheap battery bank. Now remember that there was no Axpert. The cheap inverters weren't all that appealing anyway.

So when I say that both approaches are valid, I mean it. I had to pick something to skimp on, and I did. Yes, that's not a good recipe for Joe Public who wants it to "just work" (tm).

For a small bit in the middle there, I very almost went with a 48V 3KVA Multiplus and even cheaper batteries! That would probably have been even better. But we compromise and we live...

+1 on the choices I also had to make.

Tried a few UPS inverters, then had a Cotek and nearly tried a Meanwell. Ended up paying tipple for the blue in the end. Was worth it when compared to what I knew then. Today I still have no regrets at all.

And a very good point made. For the Joe Public with the "just work" requirement, he is "just going to pay a lot" to be done with it.

 

Will I swap around and buy expensive batts? Hell yes. 1000ah 2v ones if Eskom goes bos and leaves us in the dark again or if I decide to go off-grid.

Then it will be a Blue 12v 5000VA - daytime high loads, evenings small ones - and be done with it.

Who cares if I have to put in AWG 0000 cables - I can because I am.

Yes but remember this all started on what would be the most economic way of going solar? Isn't that  that basis from which all decisions must be taken of? 

If your need is to save as much as possible and increase your disposable income so that , in your golden years , you would not need to look into someone's eyes for sustenance you will have to make lifestyle changes and that will include creating a "new hobby" for yourself and on that basis @The Terrible Triplett is spot on with his take on the batts. 

On the other hand , if you want to move on principle , the worst kind of decision (IMO) , to solar and you want a out of the box solution.. Then open the floodgates because you will need to throw money at this and that will include buying the meanest bank of batts.  

You can not compare the simple math of R,c against principle as principle does not have an intrinsic value. 

As per usual my 5c worth ...... 

I agree with @KLEVA on this matter.

Reasoning for this is I see the "better" batteries more like a "long" term investment than anything else

Lets take what @plonkster calculated my Trojan T105 RE bank at (Think we worked out R2.34 per electricity unit)
I'm running my bank to 80% SOC only for now so that's about 4000 cycles (10.9 years) I hope to get out of them.

Now lets take a look at Eskom they increase on average around 10% every year.
My prepaid rates will be the following amusing a 10% increase every year.

So as you can see staying in block 1 and 2 for Eskom is my goal.
Now the long term investment starts at year 4-5 as block 1 is still not to bad then but 2 starts getting to that magic number worked out earlier.
Years 6 - 11 if I make it will be just the gravy as my batts will still be costing R2.34 a unit.
Here you start saving up for the new bank again.
 

If I delayed my purchase of the better batteries for later they would just be a higher price thanks to inflation and the cycle would work out the same
just at a later stage.
From now on it's just rinse wash repeat.

If you think Eskom rates won't keep increasing then I say good luck to you.

That figure is closer to R6.00 per kwh as you need to add in the replacement cost of the batts (Remember you are paying upfront now most of the times with borrowed money) and will need to buy in 10 years time again, then you also need to add the risk involved as the batts does not carry a ten year guarantee on them.

Even with eskom beeing what they are they also do these maths..... 

If you have eskom use them for batts at night and drop base at nigth , save that money for the batts and if we get to the stage were we will haveto go off grid buy them then....

Viper, yes, the sums you make are in line with all the solar calcs I have seen, taking into account the savings on Eskom with estimated Eskom increases. the larger sums tend to favour solar over +-7 years where you break even, thereafter it is all "free"?

But there are substantial flaws in that.

None of the calcs I have seen took into account not only the cost of battery replacement at+-10 years (with inflation as with Eskom inflation), inverter (with inflation) replacement at any time and the 20 year panel replacement costs (with inflation). Panels may not last 20 years as you will see a marked decrease in your power generation over time.

Yes, panel costs have reduced but the more common they get, the more expensive they become. Same with Axperts, they are going to increase over time also.

And less we forget, the interest charged if you bought solar on a loan. I think of the Milk money systems Edmund coined when interest comes into play.

Never have I seen a comparison of reducing your load to the lowest you can at night, using Eskom, with solar power daytime and putting the monies spent on the large expensive bank into an investment account over the same 10 year battery replacement period.

As Paul said, I am practicing for my retirement one day. 

Who can do these sums, for only then can one get to actual costs, assuming Eskom increases as well as the inflationary cost of replacement.

Another factor these sums mis, as I have been doing for years now when there are annual Eskom increases, I systematically reduce the overall load using Milk Money so that I stay on +- the same Eskom cost per month. Things like reducing PSU of the computers that have to be on for work, Pi's to watch movies, QNAP as the media centre, Kindle on cellphone, lights off when no-one is in the room, shower daytime and not use Eskom to heat the water, old batts to power the remaining lights, etc etc etc.

Things like the cost of food increasing each year far exceeds Eskom costs and then buying in bulk yet not have a large fridge but a bunch of small ones you can switch off if they are empty, all running of a small expensive bank, in the 80% SOC range ... all small little projects I do to reduce the big picture, staying very far away from a large expensive bank.

It took me years to realise solar is a very expensive mistress, but she taught me "Needs versus wants", which is a BIG subject that always gets emotional.

Today I considering the big picture of living and the footprint I leave, thanks to my solar journey. 

55 minutes ago, The Terrible Triplett said:

Viper, yes, the sums you make are in line with all the solar calcs I have seen, taking into account the savings on Eskom with estimated Eskom increases. the larger sums tend to favour solar over +-7 years where you break even, thereafter it is all "free"?

But there are substantial flaws in that.

None of the calcs I have seen took into account not only the cost of battery replacement at+-10 years (with inflation as with Eskom inflation), inverter (with inflation) replacement at any time and the 20 year panel replacement costs (with inflation). Panels may not last 20 years as you will see a marked decrease in your power generation over time.

Yes, panel costs have reduced but the more common they get, the more expensive they become. Same with Axperts, they are going to increase over time also.

And less we forget, the interest charged if you bought solar on a loan. I think of the Milk money systems Edmund coined when interest comes into play.

Never have I seen a comparison of reducing your load to the lowest you can at night, using Eskom, with solar power daytime and putting the monies spent on the large expensive bank into an investment account over the same 10 year battery replacement period.

As Paul said, I am practicing for my retirement one day. 

Who can do these sums, for only then can one get to actual costs, assuming Eskom increases as well as the inflationary cost of replacement.

Another factor these sums mis, as I have been doing for years now when there are annual Eskom increases, I systematically reduce the overall load using Milk Money so that I stay on +- the same Eskom cost per month. Things like reducing PSU of the computers that have to be on for work, Pi's to watch movies, QNAP as the media centre, Kindle on cellphone, lights off when no-one is in the room, shower daytime and not use Eskom to heat the water, old batts to power the remaining lights, etc etc etc.

Things like the cost of food increasing each year far exceeds Eskom costs and then buying in bulk yet not have a large fridge but a bunch of small ones you can switch off if they are empty, all running of a small expensive bank, in the 80% SOC range ... all small little projects I do to reduce the big picture, staying very far away from a large expensive bank.

Another cost, which many fail to think about, is that a solar system adds value to your life. I'm not talking about direct savings from Eskom, alone. Think about this: My wife's office is at home, and every time she had to start the genset, or drive to a mall to work, she lost valuable time. And spent money on petrol for the genset (in 2008 we averaged on about R1200/pm on petrol!), unnecessary running costs on the car, unnecessary coffee + snacks money, etc. The time she lost with all of this is worth more than what was spent just to work. As an ex-IT support engineer, we used to charge R900/hour for consulting / support. So, 30 minutes TO the mall, 30 minutes to setup + shutdown & pay afterward, and then another 30 minutes back = R1350 LOST. And you can't claim that from SARS either. Her hourly fees are quite a bit less, as a webmaster / marketer, and art teacher. But it's still more expensive than trying to get working again after being disrupted due to downtime. 

Now, let's take it to the next level: Friend of mine has an engineering shop. We calculated one day, if they were "offline" for 4 hours, they lost about R40K, just on the jobs that stood still. Wages and other problems that arose from it also cost extra money. One client runs a restaurant. He also said they lost between R30k and R60k, everytime there was load shedding, depending on which day it happened. i.e. Fridays and Saturdays they lost the most. Their R250K "loadshed kit" was a no brainer. The mall didn't allow for solar panels or generators, so they got a nice big battery bank and couple 3 phase inverters to run their shop. 

 

Here you can't work on R/Kwh alone.  

But that is what you just did.  The math made sense,  they paid the set off with in 6 loadsheds.

You cant fail the numbers..

YES Silver, spot on. The numbers make complete sense in those cases.

Lest we forget, the UPS industry is quite mature and can sort those type of needs quite nicely.

1 hour ago, SilverNodashi said:

adds value to your life

Yup. Some points on that.

1. My system is paid off. Because the ROI wasn't measured in the electricity it made. It was in the hours NOT lost during load shedding.

2. It's funny how the wife got on board. Power fails at the office, she announces: I'm going home, I have power there! And away she goes.

3. Kids are scared of the dark. When your lights continue to work, it really helps them.

4. Summer heat. When you can run a fan in the kids' bedroom even when the power is down, it helps.

5. A stepping stone to bigger things. I'm a software developer, so way more of my passion for this lies with the control- and management aspect. I learned very quickly that people who sit on both these chairs are very rare. Now imagine what that is worth on a CV!

6. Now that I have a bunch of paid-for equipment, there is another investment rule that comes into play: You don't look at historical performance, only future potential (though one may of course be an indication of the other). For example, you bought a house and planned for it to pay its own bond in 5 years, but it took 10. You don't look towards the extra 5 years of lost money you had to sink when you decide whether to keep it or drop it. You look at the rental potential NOW. In the same way, the question for me is how much will it cost me now to reduce my consumption NOW. And the answer provided by a hub-4 setup combined with ignoring the historical performance (which is poor in terms of power made vs cost) says that potential is excellent.

The challenge for me, as a software/sort-of-embedded guy, is how do you get the interconnecting integration stuff to be cheaper. How do you replace the expensive CCGX with something simple that "just works" and doesn't cost more than the charge controller? With our power situation as it is, people are still willing to pay for a good UPS, so that in many cases you can ignore the ROI (in terms of generated power), and the energy saved becomes a useful extra feature (though the real product you sell is backup). I think there is a massive case to be made for this :-)

My system is cheaper than what Eskom was costing me. I was paying an effective R5+/kWh, and the less I used, the worse the cost got as the fixed line cost was so high. If I got my usage down to 200kwH/month, I would be paying R1400 (R1200 line + R200 usage), so an effective R7/kWh! Easy to make a case for solar with those prices. My system will be paid off fully in 3-4 years (so about 2 years from now). But here's the great part, I have paid the money already, and it is long gone and forgotten about, so what I have now is completely free electricity (apart from the battery replacement costs when they arise). So for me, solar is just plain cheaper in cash money terms, and the more Eskom pushes up their price, the shorter the payback becomes.

1 hour ago, DeepBass9 said:

My system is cheaper than what Eskom was costing me. I was paying an effective R5+/kWh, and the less I used, the worse the cost got as the fixed line cost was so high. If I got my usage down to 200kwH/month, I would be paying R1400 (R1200 line + R200 usage), so an effective R7/kWh! Easy to make a case for solar with those prices. My system will be paid off fully in 3-4 years (so about 2 years from now). But here's the great part, I have paid the money already, and it is long gone and forgotten about, so what I have now is completely free electricity (apart from the battery replacement costs when they arise). So for me, solar is just plain cheaper in cash money terms, and the more Eskom pushes up their price, the shorter the payback becomes.

your line fee is / was cheap. On the farm, we used to pay R1500pm, upto November when I installed a nice 9Kw PV array + 4x Axperst inverters

Like the rest of us, not being on a farm like me:
Connection fee: R0.00
Any other fee for Eskom: R0.00

I just pay for what I use. So I need to be very wise and careful with batteries. 

So what would you say is the cost per kWh that makes solar feasible? R3?, R4?

1 minute ago, DeepBass9 said:

So what would you say is the cost per kWh that makes solar feasible? R3?, R4?

Today, must be less than R2.28 kWh.

On a farm with Eskom connection fees, or generator costs, it is a no brainer. Dump Eskom connection, spare the gennie and go full out solar, with good batts ... 48v.

For the rest of us at home it is not that easy, sorry. As I said above one has to factor in all the costs over X period to generate your own power. My top rate is R2.28 per kWh ... solar has to be below that, with batt replacements ... and boy I tried.

The problem with solar in cities for home users are the battery prices, not the inverter, not the panels. Grid tie is THE best option, T&C apply.

To do it cheaper than Eskom, in cities, for your home, is a real challenge.

7 hours ago, PaulF007 said:

That figure is closer to R6.00 per kwh as you need to add in the replacement cost of the batts (Remember you are paying upfront now most of the times with borrowed money) and will need to buy in 10 years time again

Why should this be factored in when comparing running costs of the bank vs Eskom?
You pay for electricity(80% SOC everyday) upfront for the next 11 years with a good set of batteries not for the next 22, so working in replacement costs should not be part of the equation here.

I'm just heading out for a couple of hours will come and explain later on. 

Here is a though for deliberation.

The cost per kWh that I pay is all inclusive R2.28 - inclusive of all repairs and maintenance and a bit of profit and some for the poor.

Cost of that kWh that municipality paid Eskom last year was alallegedly R0.55c (incl) per kWh. That includes Eskom's costs to generate and distribute it to municipality, with repairs, maintenance and profit for them.

Can I do it for R0.55c? Maybe with grid tie with no connection fees payable maybe.
Can I do it for R2.28 with batteries, nope.

@The Terrible Triplett are you paying R0.55

If not how is this even relevant?