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Hi Everyone,

I am new! I am in Jo’burg and I want to make my life better by  investing in some backup and solar power for my house.

I have done a bit of research but I now need to get into action. I am planning to install a system according to the following steps:

  1. Backup for load shedding and power interruptions: 5kW inverter and 5kWh LiFePO4  Battery with only essential items on the system.
  2. Start generating own solar power,  gather more information and start to optimise: Add two strings of solar panels in different locations. Move some loads over.
  3. Increase storage and panels: Add a 2nd battery, increase PV panels,  reduce loads and reduce peak consumption.   Move more loads over.
  4. Go off grid:  Add a 3rd battery, a 2nd Inverter and more panels if required.  Off grid!!

Final setup expected to be something like: 2x5kW Inverters in parallel, 3x5kWh LiFePO4 batteries,  4 strings of PV with approximately 10kW of panels.

The inverters should have own charger, MPPTs, smart load, gen connection, battery interface, WiFi, protection, etc. Batteries should interface with inverter and have own BMS.

I have decent roof space but the biggest part of the roof is not facing perfectly North, more like ONO. Other smaller roof sections face NNW or are flat.  Some shading on most parts except for the flat part.

My idea for where the batteries will fit is somewhat restricting and that influences the physical dimensions of the batteries I can choose from.

 

We are 5 people living/working/studying from home.  Current consumption is about 24kWh per day with a rare peak of up to 8.5kW.

Big consumers are: Electrical backup for Solar geyser (4kW with Geyserwise mostly required only in winter), Pool pump 0.75kW for many hours,  Electrical Oven max 4.2kW, Borehole pump 1.1kW and various other smaller users.

All my lights are already LEDs, stove plates are all gas, other geysers are gas,

I also have a 2kW generator which I can use in case of poor PV performance or other problems – currently my load shedding backup.

I do not have the funds to install everything at the same time but I need backup power asap to allow working and studying from home.

To achieve full saving on municipal power I hope to eventually disconnect to have no Service charge or Network charge anymore.

I plan to do most of the installation myself and only get in the professionals for final connection/change over and commissioning.

Apart from the above solar solution I also plan the following:

  • Reduce peak power use as much as possible by reducing and staggering loads.
  • Install a 3kW PTC geyser element rather than the standard 4kW I have now.
  • Pool blanket to reduce pool pump running hours.
  • Move some consumers to sunshine time to reduce battery need.  E.g. pool pump, borehole pump, geyser,
  • Geyser on Smart load (only receives power when battery full and PV power good) or heatpump or more solar collectors or a another solar geyser for winter in series to the current one.

Now I have the following questions:

  • Any advice or inputs on the above plans?
  • Any experience with similar setups which can be shared?
  • Looking at my steps and my final setup – do you think it is going to work out?
  • Any other recommendations for optimisation or improvement?
  • Any recommendations on specific equipment? My current favourites are Deye Inverter and Freedom Won batteries.
  • Are there any forum members who would be willing to send me a quote for supply of equipment and/or installation?
  • Are there any forum members with advice on where to get good prices for any of the above components?
  • What are the requirements for such a system?  Standards to comply with?
  • What are the approvals I need before I can start with my plan?

 

Thanks in advance – I see there is lots of good advice on this frum and I hope to learn a lot.

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Hi Strepies,

Great plans that you have there & all of your points are spot on. You need to build up such a system as you said as & when you can afford to. 

If I can advise you, the best steps are to decide on what is important first as in your post you mentioned you need backup power. So start off there. You mentioned you have a Generator 2kW. If you purchased & installed an inverter & battery pack without PV solar input, all you have is a silent generator. You save nothing because you will charge from Eskom & use during outages. But it's the first step in your journey. Then adding panels will be the next or maybe you have the funds to get this in one bang. You can add as your pocket allows & it's like building up a sound system. Try to buy quality & build at your pace & enjoy your system & journey doing it.

Your action plan in points 1-4 are exactly spot on & are the natural progression. 

However, ask yourself these questions:

1) How much can you afford right now? This will determine how deep you can travel on your 4 point plan.

2) Equipment selection to execute that plan? IE. Inverter brand, battery brand, long term planning. 

I can't ponder nor can I answer all of these questions you pose & I guess the replies you will get will in combination give you a richer understanding of how to achieve what you ultimately want to build.

All I can say is that, your thoughts & ideas are headed in the right direction.

87

 

 

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Welcome and thanks for the detailed post makes it very easy to help.

Congratulations on being halfway offgrid, since you already have hot water and gas for cooking. That usually takes more than 50% of electricity in a household. 

My first suggestion is to look at changing your 4kw element to the 1,5kw or 2kw geyserwise ptc elements. Doing that gives you peak loads of exactly 5kw.

 

Which means you might only need one inverter. You are spoiled for choice in 2021 when it comes to hybrid inverters. The powerforum store has the sunsynk 5kw and solis 6kw hybrid inverters at very attractive prices. The choice of inverter will guide the choice of panels that match the mppt requirements(11A vs 13A imp).

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8 hours ago, Strepies said:

My current favourites are Deye Inverter and Freedom Won batteries

Your plan/steps taken sounds spot on

Great choices, I would get the 8kw machine once off coz if need be for more power (budget depending of cause rather save up)

I have the sunsynk version and they work excellent

Edited by Quwatush Shams (Suly)
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Going completely off grid means investing in a lot of expensive batteries for when you have a long stretch of cloudy/rainy days, in Cape Town we have around a R180 service charge per month, I would not consider the expense of going fully off grid.

    what part of the country do you live in ?

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Looks like allot of thought went into this. 

Depending on your budget, i would target the reduction of your dependency on eskom first. As much as getting a battery and an invert would cater for load shedding, your consumption is still slightly high. 

Consider getting few panels, 6 - 8 when installing the inverter and the battery. That way you killing two birds with one stone( catering for load shedding and reducing the monthly cost). Also look into a smaller element for your geyser, belive me, it makes such a huge difference. I just changed mine from 4KW to 2 KW, now my solar production is enough to cater for geyzer and house consumption. 6KWH production maxing at 4KWH. 

Look into Hubble and Sunsynk, currently using sunsynk and loving it, unfortunately i cant comment on the Hubble but allot of guys have mostly good things to say about it. That should set you back R50K for inverter and battery, then panels 6 x 455W canadian solar should be around R15K then installation and accessories. 

I built my system over phases, within four months and i feel i wasted money by going the gell batteries and growatt inverter. 

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12 hours ago, Tariq said:

what part of the country do you live in ?

@TariqI am in Johannesburg - I do not blame you for missing that in that long post I wrote....🙃.  I am not sure whether we have more or less rainy days in a a row compared to Cape Town - is there a place to find such info?

What I do know is that monthly we have a Service charge of R169.29(excl VAT) and a Network Charge of R498.72(excl VAT) plus another "Network Surcharge kWh" which is between R10&R20.  With Vat this adds up to R780 per month - just like @87 Dream mentions I definitely want to stop paying that.  While connected I will be paying that even if I do not use anything.  This is a lot more than what you have in Cape Town @Tariq.  This is also in line with what @nightcrawlernic says - once I start spending money on panels I want to end the eskom nightmare fast.

@nightcrawlernicFor my "data collection" step I am thinking of putting two small strings of panels in two different locations to get an idea of which location is better.  Afterwards I may put them all in the best spot.  I am now wondering how much the results will differ between summer and winter even if I test the two locations at the same time. One spot may be good for summer and the other for winter - is there any wisdown out there.  Two of the locations will be same angle but one is facing NNW and the other ENE.

My geyser is 300liter and I am worried that a PTC element smaller that 3kW will take hours to heat the water - any experience on the forum?

I am planning to put my batteries in the back of 4 identical kitchen cupboards of which only the front part is used.  I realised that it is only the smaller Freedon Won Lite 5/4 and the Kodak FL5.2 that will fit into these spots.  There are other locations which are more exposed to the elements and possibly even a theft concern.  With my ;preferred location I am making my life difficult in a few ways:  I am limiting myself to more smaller batteries, I am limiting myself to very few manufacturers, and the batteries will be in the back of a wooden kitchen cupboard - Do you think I am foolish to apply these limits to myself? Is there any danger with such a location? (I will add some vents)

Thanks so far everyone!  I am awaiting any further inputs.....

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14 minutes ago, Strepies said:

I am now wondering how much the results will differ between summer and winter even if I test the two locations at the same time. One spot may be good for summer and the other for winter - is there any wisdown out there.  Two of the locations will be same angle but one is facing NNW and the other ENE.

I am also on the Highveld in Jozi, & the data collected first hand from my property & also with experience in the installation business is the following: in Summer we have more Sun hours as Sunrise takes place earlier & Sunset later. However, with the higher sun hours also comes the highveld weather, clouds & most rainfall is experienced in the summer months. So these two factors offset each other slightly. 

 

However, what the trends show is that even with the cloudy weather taking place only late afternoons, you end up with peak output by noon or so. So you maximize your morning output in Summer & the afternoons are not as good as one can expect. Still lots of light but not constant. The winters have massive potential but the late Sunrise & early set make for less sun hours on average. 

Yes the angle of the sun is also different as per seasonal change. High peak in Summer lower in Winter. In the southern hemisphere ideal facing should be North. South Africas Latitude is +-S28°. So you panels AVG angle should be +-30°. The avg rule of thumb is PV angle is the Latitude of the location of installation.

With regards to which site will get more sun. Ideally, you want your panels facing North. However, if not possible you can face E or W if your roof allows. If your inverter allows like the Axpert MAX with 2 MPPT inputs if a site is limited in orientation sometimes one string E & one string W is the best of both worlds of peak. The midday peak is a good double avg. The E will peak well in the morning & the W by afternoon.

So NNW & ENE can be done but not to the best results however, I'd be willing to suggest NNW would be better as it's more north by orientation. In NNW you will have better results as said above & later peaks as it's facing more W. ENE will be less production but have a higher morning peak & drop off earlier.

My word I think I have lost myself in this fishpaste of direction finding...😂😂😂☀️

Hopefully I have not lost you in my translation of this topic. Probably some clever ppl can explain it more simpler.

87

 

 

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Good morning.

1. what Equipment. Inverter DEYE 5kw x 2 Battery Lithium batteries SA 5,1kw X4 Solar panels as big as you can afford. 

2. Start off by purchasing 1 inverter and 1 battery total cost around R40k, Install this properly on your essentials,

3. Purchase enough panels to fill up one MPPT on the Deye. 3500watt

4. Purchase enough Panels to fill up the second MPPT on the Deye. 3500watt

5. Save and purchase your second Deye and second battery. 

6. follow steps 3 and 4

7. Purchase more batteries.

Switch eskom off. 

If you have a borehole get yourself a tank as well as a proper filter system and pressure pump and reduce your water usage as well.

 

 

 

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look at Sunsynk versus Deye, much better interface and the ceo ( Keith Gough ) is much more involved with clients and pus on a lot of training videos on YouTube, the cost is only a few hundred rand more.

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You don't need rainy days to reduce your system's output, just overcast days. We had a long spell of overcast or partly overcast days in Jhb earlier this year. This is why it's expensive to go completely off grid - you need to have a lot of stored power or some other source of power to see you through such spells.

If your provider is City Power, I recommend using a hybrid system and converting to pre-paid. I will go into some detail about this later, but there's no fixed charges on a pre-paid connection (so far, for 3 years now they have considered a R200 per month connection fee). So buy some units each month to stop the municipality snooping around - which they have done to me.

The logic is this: If the weather is gloomy, or you have some unusually high loads, then you can draw from the grid as long as you have a credit on your meter. I don't know what the threshold is at which City Power decide to come and see if you have bypassed your meter, but start off with something like 200 units every 3rd month and see how that goes. Remember that once the units are loaded on your meter they don't expire, they stay there. I have about 4 years credit (at current consumption) on my meter.

All that said, first find out what it's going to cost to convert to pre-paid. It is not free, and prepaid users pay more per kw/h than post paid users do. But because the fixed charges for a post-paid connection are in excess of R700 per month you will soon make the money back. Also it will be costly for a couple of months because you will be paying off the post-paid account AND feeding the meter. This happened to me for 2 months, then on the 3rd month I got a credit on my account. The installer will read your meter at cut over time, and the meter will come loaded with a few kw/h so that you are not plunged into immediate darkness. Buying units is pretty easy - I buy them using the banking app on my phone, but there are many options (including supermarkets). 

A hybrid system will use a little grid power each day because it has to constantly synchronise with the grid - same voltage, same frequency. In weather like we are having lately I use 0.8 to 0.9 kw/h per day. BUT when the grid is down most of my house keeps on running off of the batteries and solar. If it's gloomy and we have load shedding I can charge my batteries from the grid ahead of the shedding.

Or you can buy a decent generator that your inverter can control. Then you can be truly off grid, but you will have costs for fuel and servicing.

PS: I have 6 panels facing north and 6 facing east. My peak production time is about 11:30, with the east facing panels kicking in early and then producing useful output until about 15:00. 

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@87 DreamNow I thought of something else - I assume if we talk about North for the sun we are talking about True or Geographic North.  And a compass reads Magnetic North.  I assume my Samsung also reads Magnetic North.  I checked my magnetic declination here https://www.magnetic-declination.com/ and found that it is -19° 16' at the moment so I have to apply a correction as follows to confirm exactly which geographic direction my roof is facing.  Not that I can change it 🤪

image.png.6af2d335218a6ec6a5c34cc517a4ad0c.png

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I think that in your case, you have what you have. You know roughly which direction your roofs are facing & are unfortunately stuck with this orientation. Not much you can do about that.

Variation, Magnetic North & True North are used more for the Aeronautical guys. True north even more especially used when you get above 70° latitude & a normal Compass becomes useless as it points to the ground. What you have are fixed roof surfaces & you can view the daily suns path. Seasonal change will also make that path not constant anyway. The orbit of the earth around the Sun & the Axis of the earth will make the Sun's rays not the same path by Summer Vs Winter.

What you view on a Compass or App will in my opinion be more than good enough at South Africa's Latitude. You cannot change the roofs direction.

You have a mainly North & East roof orientation is what is more important.

Some good info there from @Bobster & also paints the picture into why completely off gridding can be $$$. The expensive part of it is the storage capacity. Imagine 3 to 4 days of non optimal output. Hence 3 to 4 days of backup storage capacity. So that would equate to +- 40kWh of Battery Capacity. Eye watering stuff 🥺

87

 

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  • 4 weeks later...

Hi Everyone, I thought I should let you know that I took the first step in my plan.....

I am now owner (and operator)  of a Deye 5kW inverter and a Freedom Won Lite 5/4.  I did the installation myself with the intent of getting a professional in to do the final checks and commissioning.  Then there was the threat of possible load shedding and I thought it was going to affect us so I started things up making double sure about everything I did and checking things many times.

Everything went well with no trips, surprises or any smoke coming out.  My system has now been running for 14 days and as things go we have not even had one power interruption.  Is it wrong of me to  hope for one?

Here and there there are a few things which I suspect I can improve but I will first try and study previous posts and if required post where more appropriate.

Thanks for all the inputs - I will be tapping your brains some more in the near future.

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42 minutes ago, Strepies said:

Here and there there are a few things which I suspect I can improve but I will first try and study previous posts and if required post where more appropriate.

Thanks for all the inputs - I will be tapping your brains some more in the near future.

Congrats Strepies, welcome to the club!! Can't think of any person in this game who can just sit back & say any installation went off perfectly & that there is no improvements required. 

Also well done & taking it on yourself. Many ppl out there lack the courage & I'm guessing you are well competent enough especially if the machine is working without fault. 

Kudos to you Sir 👏🍺

87

Edited by 87 Dream
One day I will learn to spell
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