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Heya all,

After much lurking, and even more convincing of the SO, I think we might be ready to get into a solar kit for the house.

We currently use most of our power during the day and below is our current pretty normal consumption, yes its high, but there are specific reasons for that

 

Looking at getting something along these lines: https://solaradvice.co.za/product/fusion-8kw-pylontech-3-5kwh-lithium-ion-solar-power-kit/

Thinking of going 16X 400w Panels, 8Kw inverter (Is this Fusion one decent? the Dyes seem to come well reccomended), then 14 KW/H of Pylon USC3000's

Idea it to keep it as simple as possible wire everything in, an use eskom for the excess. During Poweroutages, then be sparing on the batts.

Would my plan be sound, and could i put this together better?

 

image.png.daffbe94f044c027d7b68ea69aa019af.png

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I have a 8kw Sunsynk and it kicks ass.

All inverters have specifications regarding the panel watts (not really relevant) and the maximum dc voltage (most relevant).  You need to do some reading on this topic on the forum. 
It is also a good idea to get an idea of your consumption by measuring it. 

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As mentioned. The inverter looks like a rebrand deye/sunsynk inverter. I would check what the user interface on the inverter looks like as well as what their support is like. I know the Deye and sunsynk are fairly well supported. 

If you can, look at increasing your panels to about 8kw. I am generating 55kwh on a good summers day in CT with a low of about 15kwh on a very overcast day. Maybe one less pylontech to get the extra panels. I have 28 x 305w panels and 3 x 3.5kw pylontech batteries. 

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Cool thanks guys, not sure if I can fit many more panels on my roof.

is solaradvice good as an installer ?
 

Otherwise happy for any recommendations in the JHB area 

will also do some further inverter research , I’ve got some friends with goodwe’s which also seem pretty good 

 

 

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3 minutes ago, Justin_A said:

Cool thanks guys, not sure if I can fit many more panels on my roof.

is solaradvice good as an installer ?
 

Otherwise happy for any recommendations in the JHB area 

will also do some further inverter research , I’ve got some friends with goodwe’s which also seem pretty good 

 

 

You can reach out to @Leshen, his done a few installs in and around JHB.

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I would suggest highest power rated panels like those 455 watt ones or higher if roof space is limited.

If you generate more power you can use more and you can store more. If you have lots of storage but not enough production you might struggle to charge your batteries.

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23 hours ago, Vassen said:

Also bear in mind that 1 pylontech battery will only be able to give you a peak power of 1.7kw. If you can manage to keep your loads below this, then it will be fine 

Hi @Vassen

Please clarify this for me. Does it mean that even if I have an 8kw Inverter, the output when using the Pylontech battery will only be 1.7kw?  

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23 hours ago, Vassen said:

I suggest you check with PF store as their pricing is also very competitive. 
 

that solaradvise kit is basically charging you around 34500 for the inverter and around 18000 for the battery. You can increase the quantity of items and see the difference in total. That to me is nothing special as it’s normal pricing. You will also need to factor in combiner boxes and other items like changeover, breakers, surge protectors into the quote. For the smaller items you can also shop around. 
 

regarding the inverter itself, the fusion seems to be a rebranded deye. Physically they should be the same but the GUI and support may be very different. Sunsynk is great, deye has improved a lot recently and not sure about fusion. 
 

Also bear in mind that 1 pylontech battery will only be able to give you a peak power of 1.7kw. If you can manage to keep your loads below this, then it will be fine 

If I may ask, how did you come up with 1.7Kw? and which Pylontech battery are you talking about? the 2.4Kw one or the 3.5Kw?

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2 hours ago, JK844 said:

Hi @Vassen

Please clarify this for me. Does it mean that even if I have an 8kw Inverter, the output when using the Pylontech battery will only be 1.7kw?  

The pylontech battery management system limits the charge and discharge currents. If you have 1 x 3.5kw pylontech battery then it willing this to 1.75kw. I have 3 x 3.5kw pylontech batteries connected to my 8kw inverter and it will only charge you discharge up to 111A or about 5.25kw.

This only applies when running only from batteries. If there's solar or grid available it will increase the output and blend from these other sources. 

Edit 

Pic from my inverter indicating charge and discharge limits. The BMS will change these values based on the SOC of the battery. 

Screenshot_20210110-195123_Gallery.jpg

Edited by Achmat
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Thanks all for the info and replies, so I think that the below might be exactly what I'm looking for, it will basically turn Eskom into backup for cloudy day / us turning everything on on the same day silliness backup. The sunsynk also looks like what I might be looking for, however its not clear if it has an IOS app for monitoring and control, anyone had any experience with that?

https://www.solar-shop.co.za/hybrid-solar-kits/366-sunsynk-8kw-hybrid-pv-kit.html

I've also realised that I have a large portion of flat roof in front of my sloped tile roof, all more or less facing directly North, so if I get a frame for panels put into it then I actually have plenty of roof space, even though it might cost a bit extra for the install.

Now just to find an installer and see if I can find better pricing on all components needed.

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7 minutes ago, Justin_A said:

Thanks all for the info and replies, so I think that the below might be exactly what I'm looking for, it will basically turn Eskom into backup for cloudy day / us turning everything on on the same day silliness backup. The sunsynk also looks like what I might be looking for, however its not clear if it has an IOS app for monitoring and control, anyone had any experience with that?

https://www.solar-shop.co.za/hybrid-solar-kits/366-sunsynk-8kw-hybrid-pv-kit.html

I've also realised that I have a large portion of flat roof in front of my sloped tile roof, all more or less facing directly North, so if I get a frame for panels put into it then I actually have plenty of roof space, even though it might cost a bit extra for the install.

Now just to find an installer and see if I can find better pricing on all components needed.

They have a Web portal. You can also check the store for an app called Solarman. They have 4 android apps but not sure if they have any iOS apps. 

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On 2021/01/15 at 4:51 PM, Brani said:

From this production, about 10-12kWh will go to the batteries. Your should expect your electricity bill to be halved, and batteries to last you until around midnight or maybe a bit longer. 
Your payback should be around 8 years and you have some backup for load shedding, if this meats your expectations.

I am interested in these figures. I am not dismissing them. I have 10kw/h of batteries, 12 * 375 watt panels and a Goodwe ES and I can't see myself breaking even in even 10 years. OK... I had to pay the cost of installation (folks who can do that themselves will save) but even so the model that I am building in real time as I get data each month has me taking a lot longer to pay back than the 9 years I originally guesstimated. 

Like Justin_A I was not using a lot of power before changing to solar, and still am not. The municipal bill was very rarely for more than 500 kw/h in a month and average was about 470. OK... this makes payback harder if your system doesn't work 100% all the time. Mine doesn't because where I live, selling back to the municipality is possible but not economically viable. Maybe this is why I don't see an 8 (or 9) year payback. OK... that may happen if Eskom get some big ass increases in the next couple of years, but right now I don't see it.

Which is not to say I wouldn't do the same, because there is a value other than what we save on the municipal bill.

But I'm interested in how people do these sums. It is possible that mine are very, very wrong and I can build a more realistic model of when I break even.

(Basically I just looked at what it was costing me a month, factored in the already announced tariff increase for Jhb, factored the same percentage in for another couple of years, then thumbsucked 10% PA thereafter and naively assumed that the system would generate all the power I needed all day every day. This was naive because I wasn't thinking about very overcast days like we've had the last couple of days. And on that basis it was about a nine year pay back.)

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43 minutes ago, Bobster said:

I am interested in these figures. I am not dismissing them. I have 10kw/h of batteries, 12 * 375 watt panels and a Goodwe ES and I can't see myself breaking even in even 10 years. OK... I had to pay the cost of installation (folks who can do that themselves will save) but even so the model that I am building in real time as I get data each month has me taking a lot longer to pay back than the 9 years I originally guesstimated. 

Like Justin_A I was not using a lot of power before changing to solar, and still am not. The municipal bill was very rarely for more than 500 kw/h in a month and average was about 470. OK... this makes payback harder if your system doesn't work 100% all the time. Mine doesn't because where I live, selling back to the municipality is possible but not economically viable. Maybe this is why I don't see an 8 (or 9) year payback. OK... that may happen if Eskom get some big ass increases in the next couple of years, but right now I don't see it.

Which is not to say I wouldn't do the same, because there is a value other than what we save on the municipal bill.

But I'm interested in how people do these sums. It is possible that mine are very, very wrong and I can build a more realistic model of when I break even.

(Basically I just looked at what it was costing me a month, factored in the already announced tariff increase for Jhb, factored the same percentage in for another couple of years, then thumbsucked 10% PA thereafter and naively assumed that the system would generate all the power I needed all day every day. This was naive because I wasn't thinking about very overcast days like we've had the last couple of days. And on that basis it was about a nine year pay back.)

What I did was to look at my average tariff from my last CoCT bill. I was being charged on average R2.50/kWh. My setup including installation has set me back R200k. At current CoCT tariffs and without taking into account increases over next 10 years, I will need  generate 80MWh in order to have paid the R2.50 CoCT tariff. I.e. R200 000/R2.50 = 80 000kWh (80MWh)

Based on the last 6 months of data since commissioning the system, I should be able to generate 12MWh per year. At that rate I should be able generate 80MWh in 6.67 years. This is however including feeding in excess pv. Even removing this from the equation I am looking at 8.5MWh per year and payback in 9.42 years.

This is however working backwards without factoring in any future electricity price increases. I'm on 178 running days so far and already generated 7.23MWh.

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my bill used to vary between R2500 min and R3000 max. December, Jan and crossing my fingers to get through Feb, I have paid R0 for electricity. the last time we paid for electricity was in November before adding more PV panels and extra two Pylons. I did the installation myself and the whole system cost me less than R140k. Assuming I pay R500 every month and save R2000, using the minimum amount I used to pay. that is R24k a year and in 6 years the system would have paid for it's self. Not taking into consideration, the tariff increases and not looking at the benefits of having lights on when there is loadshedding and faults in my area and the smile on the wife's face everytime we get messages that there is loadshedding. Priceless  🙂

 

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43 minutes ago, JK844 said:

Hi @hoohloc

Would you mind sharing details of your system as well as a rough outline of what you’re powering with it?

Hi I'm powering the whole house with my system. Geyser is on timer and only ON during the day, from 08H00 till 11H00 then ON again from 14H00 till 16H00. Stove/Cooking time is 06:30 to 08:00, 11H00 to 14H00 and diner 16:00 to 19:00. Also have a small AC, 12000btu which runs on hot days only, not evenings. Fridge, washing machine, dishwasher, microwave to warm food and kettle for wife's tea and garage deep freezer. But now since one inverter is faulty, she uses one appliance at a time. ie when we are washing clothes, we do not cook or use the microwave and we have to manually switch off the geyser. but with two inverters. the geyser is always on during the day and we can still use one plate to cook and still be able to use either the AC, the washing machine or dishwasher 🙂

The Garage freezer, fridge, two TVs, Xbox, wifi router, alarm system, electric fence, ceiling fans are always ON. I can open and close garage doors as much as I want and never overload the inverters. But with one currently running, it has been interesting when juggling all the load without getting the inverter to scream or trip. It has tripped a couple of time before but now we manage it like pros 🙂

My system consists of the below:

 

2 x Growatt SPF 5000 TL HVM Inverters ( one is faulty and out for repairs)

4 x Pylontech US2000B-Plus Lithium Ion Batteries 

8 x JA Solar 405W Mono MBB Percium Half-Cell, wired 2S4P facing west

6 x Jinko Solar Panel Cheetah 400W Mono Perc, wired 2S3P facing East

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Just now, hoohloc said:

Hi I'm powering the whole house with my system. Geyser is on timer and only ON during the day, from 08H00 till 11H00 then ON again from 14H00 till 16H00. Stove/Cooking time is 06:30 to 08:00, 11H00 to 14H00 and diner 16:00 to 19:00. Also have a small AC, 12000btu which runs on hot days only, not evenings. Fridge, washing machine, dishwasher, microwave to warm food and kettle for wife's tea and garage deep freezer. But now since one inverter is faulty, she uses one appliance at a time. ie when we are washing clothes, we do not cook or use the microwave and we have to manually switch off the geyser. but with two inverters. the geyser is always on during the day and we can still use one plate to cook and still be able to use either the AC, the washing machine or dishwasher 🙂

The Garage freezer, fridge, two TVs, Xbox, wifi router, alarm system, electric fence, ceiling fans are always ON. I can open and close garage doors as much as I want and never overload the inverters. But with one currently running, it has been interesting when juggling all the load without getting the inverter to scream or trip. It has tripped a couple of time before but now we manage it like pros 🙂

My system consists of the below:

 

2 x Growatt SPF 5000 TL HVM Inverters ( one is faulty and out for repairs)

4 x Pylontech US2000B-Plus Lithium Ion Batteries 

8 x JA Solar 405W Mono MBB Percium Half-Cell, wired 2S4P facing west

6 x Jinko Solar Panel Cheetah 400W Mono Perc, wired 2S3P facing East

Forgot to mention that the 4 batteries last me the whole night. No AC, no geyser and no cooking after sun set. All out side lights on, indoor lights only in the occupied rooms, TVs on till around mid night because of games. Can't wait for the schools to re-open. 

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Thank you for those responses. There are two components to my conundrum. 

1) I was paying less. At current COJ rates I'd be paying about R1250 a month. So if I produced ALL that electricity it would be 127 months to break even. Ok... Future increases will reduce that 

2) I don't generate all that electricity, and even on bright days I still draw a little from the grid. So I never have a "zero day". 

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10 hours ago, Achmat said:

Another thing to consider is that a smaller system is not always cheaper per installed kwh vs a bigger system. I could have gone with a smaller inverter, 1 less battery and few less panels but this would have made the price per kwh more expensive. Economies of scale and all that. 

Diminishing / Increasing returns.

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15 hours ago, hoohloc said:

Forgot to mention that the 4 batteries last me the whole night. No AC, no geyser and no cooking after sun set. All out side lights on, indoor lights only in the occupied rooms, TVs on till around mid night because of games. Can't wait for the schools to re-open. 

Yes. My batteries get me through the night with no trouble. I assume that they start discharging at 16:00 (sometimes in the summer it is a good bit later, but this is my default) and if they are fully charged then they will get me through to 09:30 no problem. That includes running the heat pump for our hot water. That's on a timer and doesn't run at night. And we have a full gas stove. So after hours it's security, TV, decoders, fridges, charging phones and a few lights,

Like other folks have mentioned in this thread, on a clear day the batteries will be fully charged by 11:30 and thereafter the system derates and draws just the solar that it needs (in Jhb I can't make enough selling back any excess to make up for the cost of switching to the sell-back tariff). This would all happen with the pool pump going and ironing, dishwasher, washing machine etc as needed. 

Where I don't do so well is if it's not a bright day. I might get as high as 80% SOC, but I wouldn't take that for granted).

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14 hours ago, Brani said:

Hi Bobster,

Achmat’s estimation is pretty accurate way of calculating the long term returns. He has enough data to look over a longer period of time.

I would optimistically take total amount of solar panels and multiply that by 4.5 hours. That would be rough estimate of what solar can produce on average. In your case you should average around 560kWh per month. That is already more than you consume but losses on battery charging plus solar variation will set you back a bit.

My panels on a sunny day charge the battery from 30% to 100% before 11:00 and on a cloudy days like today I struggle to get to 80%. I am still in two minds if I have too many or too little panels. 
if we want to calculate payback, we must also consider that most of us don’t have cash laying around, and borrow it from the bank, which attracts interest, although I estimate that Eskom’s yearly increases will be higher than borrowing rates. 
in conclusion, average payback is about 8-10 years and for me that is acceptable, because of all other benefits that come with it.

Anyone that claims payback in less than 3 years (assuming they paid market prices)is lying to themselves or a dodgy salesman.

 

 

 

Thanks for that, and thanks to the other folks who are contributing here.

So in theory I'm fine. But there are gaps between theory and the real world. Like the multi-day streak of overcast weather we are enjoying in Jhb right now. That costs me each day, and even if the sun magically reappears and blazes for the rest of this week I can never get that money back.

Also for me the value is not on the basis of what I generate but on the gap between what I use and the movement on my municipal meter.

Caveats....
1) I am relying on SEMS portal, and when I start checking those figures I'm not sure they're all correct or even what some of them are. But all I really need it to tell me is how much I actually used during the month. It does seem to be in the ballpark.
2) Having said that I am not sure about SEMS, I am using SEMS (not the meter) to check what I am consuming each month. But this can be overcome (or SEMS can be validated).

So my calculations are
1) I consumed X Kw/h in the month.
2) This would have cost Z rand if the city billed me for all of it.
3) The pre-paid balance on my meter reduced by Q
4) This cost me R rand

So my saving in the month is Z - R.

I do agree with the points about the soft value: always having lights on, fridges and freezers always running etc.

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Hello all,

This thread seems to be discussing efficiencies and calculations of what can be got out of a solar installation.

This is my setup running for about a year now. Sales at Solarman convinced me I would be shot of ESKOM!

  18x 340W/375WP A++MULTIC PERc SCHR 50VP panels

 2x HYBRD SMRT+SchAexKl 5KW 48V9KVAP 6KVAP MPT 1/3PHAPROG manufactured 12 2019 from the label

· 8x Schubart 6-GFM-240J 12V 240AH

· 1x Geyser collector panelRetr150/215LP BlackCobal2M EFFITEMP/HP

·  1x Circulation G-Pump 12VDC 10L/min2.5M head 100CelsiusBR

·   1x Solar panel 10 Watt SM ADVANCED A+GRAD 18 VOC

At the beginning of January I decided to find out how effective this system was for reducing my ESKOM bill. For seven days I recorded the kWh on our meter = 6.5 per day. I then disconnected the solar system and ran on ESKOM only = 12.0 per day. These were days with bright sun in Pretoria. For the past three days with Eloise around and solar re-connected I am averaging 13 per day. In effect, my CAPEX has halved my ESKOM bill on sunny days! Is this what I should expect or is there cause for concern? Sorry, I don't know how to do the maths.

 

Thanks for help.

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