Another solar thread: Cape Town, Northern Suburbs

[droidx]

Yet another solar installation thread, guess these will continue to pop up in numbers.

I’ve read through historical and some current install threads. I have done some research and used online tools. Trying to stay within a reasonable budget, although inside, I just want to overspec this system for convenience, but doing so does not mean 1 component only (in my understanding, which I will clarify later) so the cost compounds very very quickly.

First let me describe my house and requirements.

3 bedroom, 2 bathroom, 1x 150L electric geyser, 1 x 0.75kw pool pump, 1 fridge, 1 chest freezer, 900mm electric oven with gas hob. Then the general appliances, dishwasher, washing machine, kettle, toaster, tv’s, etc. Most, but not all lights are led. There are 2 aircons, 1 large lounge unit (not sure of BTU, sticker doesn’t say and it was here when we moved in) and one smaller bedroom unit. Thinking of installing a 3rd in my office which has a north and west facing window, so I cook in the summer afternoons. If installed, this will be used daytime only. Unfortunately my roof alignment only allows for East/West configuration. I have no North facing roof.

We are only 2 people. Typically right now I spend around R1000 on electricity for the month (380kwh), this lasts me more than a month, I estimate 1 month 10 days, definitely not less. In summer when the aircons run more, usage may increase. We mostly use the room aircon at night, runs for a few minutes and we put it off, then on again depending how long we stay up, say 15 minutes at a time so 30minutes usage or thereabout. The larger one is used sparingly and mostly during the day. I estimate my normal usage between 10-12kwh per day, with most of it either occurring during the day or having the ability to shift to the daytime.

 

[droidx]

So here goes some questions for system planning. I aim to keep this post updated with new questions, as well as answers received for the benefit of future readers (please also correct my terminology, I will update it).

1. Given my explanation and requirements, would a 5kW inverter with 5kWh battery be sufficient?
   The general consensus is yes, it would be enough. There would however need to be active monitoring of which appliances are turned on, as too many high powered appliances could trip the inverter.
   As an example, if the oven and microwave is running along with the base load, suddenly you need to boil the kettle, the inverter might trip. This would happen during load shedding when there is no grid, when the grid is available, the inverter has AC pass through functionality which would allow top up from the grid exceeding the inverters maximum capacity.
   The ability to split essentials and non-essentials also mitigates this, you can use PV generation to power non-essentials during the day when there is excess PV, however, you will lose these appliances when there is no grid.
   The 8kW gives a little more headroom in this regard.
   Battery capacity depends on end goal, more is better but also expensive. Just make sure that the settings allow you to cover yourself for load shedding. No use spending this amount of money and you stuck without power during load shedding.
2. Would the East/West configuration be problematic? I think we use most power early morning (showers, breakfast) and later evening (cooking dinner). Midday I will monitor and check whether I can run my pool pump during that time.
   North facing is best, but East/West is better than nothing. It generates less, but over a longer period, starting earlier and ending later. It does however mean that in the early morning and late afternoon only one string is active with both generating for a short period around midday. I opted for two extra panels to hopefully offset this and @Katelknaap linked a useful tool to play around with potential generation numbers. In summer I won't be able to use everything I can generate, but I will fall short in winter and heavy overcast days. Link to the free tool:
   
   

   Home

   OpenSolar connects homeowners, solar professionals, and partners with free software to design, sell, and manage fast, accurate solar projects.

   www.opensolar.com
3. My usage indicates that a 5kw inverter would suit my needs and maybe even exceed it. Online calculators suggest I need a 3.7kwp array, I am thinking to spec this up to 5.45kwp, there are benefits of over specifying the array and I will consider doing this (12*545w panels instead of 10). The question is whether going for 8kw inverter has any benefits without increasing the panel size or battery bank?
   The inverter can blend power from batteries and solar when demand is higher than solar generation. So it will not necessarily default to the grid. Ideally your PV array matches or exceeds the inverter size, but in starting out it does not need to. The more generation the quicker the batteries will charge and the more PV is available for use. Always check the voltage of the array vs the spec of your inverter and make sure you don't exceed this, your installer should advise you accordingly.
4. To me it seems that the limiting factors in the system could be the array or the battery bank discharge rate. So if I sit with 8kw inverter and 6kwp array, I would not really benefit from having an 8kw inverter during solar hours (given inefficiencies, the 5kw should work with this array). The battery discharge rate on 1*5kw 0.5c battery would not take advantage of a 5kw inverter, let alone 8kw. If I have 2*5kw 0.5c batteries, it could take advantage of a 5kw inverter during non-solar hours, but not 8kw. Is that statement correct?
   The inverter will blend PV, battery and grid to meet requirements. The discharge or C rating of the battery determines what the battery bank can provide at any one time. A 5kWh battery with a 1C rating will be able to discharge at 5kW giving you an hour of usage. A 5kWh battery with a 0.5C rating will be able to discharge at 2.5kW giving you 2 hours of usage at a lower peak. You can increase the peak usage by increasing the battery bank size. Two 1C batteries would be able to discharge at a higher rate than the 8kW inverter can use, while 3 0.5C batteries will be able to supply at 7.5kW, which is just below the inverter capabilities.
   The inverter will utilise PV during the day, up to its peak and any additional demand will draw from either the grid or batteries depending on inverter settings.
5. The limitation of the 5kw inverter would be running energy intensive products in parallel, e.g. washing machine plus dishwasher. To my understanding, this limitation would only exist when the grid is not available. When there is excess requirement during solar hours the inverter would max out the panels and supplement from the grid and during non-solar hours it would max out battery discharge rate for essentials and supplement from the grid. Is my understanding correct?
   See answer to question 1
6. Battery bank extension: what are the drawbacks of starting with one battery and adding another in a year (besides it being more expensive in the future)? What is the maximum time that I can wait to add another battery from a battery degradation point of view? I suppose it would be best to bite the bullet and install two batteries initially, but costs continue to add up.
7. Essentials vs non-essentials: I am thinking to place my geyser, pool pump, larger aircon and oven on non-essentials. My understanding is that during solar hours, excess production can go to these appliances, but during non-solar hours they would be dependent on the grid. I am ok with this (with a small qualifying question on oven). Any advice on this?
8. I have AEG 5 burner gas stove with electric oven, tried to find the energy requirements of the oven online but no luck, will need to pull it out and check the appliance sticker. A question for convenience sake here. I want to put this on essential, simply because we might use the stove and the gas hob uses electricity to make the spark, but it works on a single plug with the oven. It is not critical, but more for convenience, I use a lighter to light it during load shedding at the moment – just fiddly. I guess I could put the oven on essential but just be conscious about not using the oven in the evenings depleting the battery, but in the event it is needed, I could run into a situation where I am depleting my battery unintentionally. Any workaround for this – keeping the lighter handy is one way.

 

[droidx]

So I have some comparative quotations from a few different entities so far.
All obtained in the last month or so. For the meantime, I will exclude company names
Quotation 1 Deye 5kw inverter, Dyness 5kw battery, 3.185kWp array:


Quotation 2 Deye 5kw inverter, Dyness 5kw battery, 3.76kWp array::


Quotation 3 Deye 8kw inverter, 2*Dyness 5kw battery, 5.64kWp array::


Quotation 4 Sunsynk 5kw inverter, Sunsynk 5kw battery, 5.45kWp array (10 year warranty on inverter and battery):



Other options:
R230k for 10kw Sunsynk combo from same company as quotation 4, but don't have detailed quotation.

 

[droidx]

Reserved for installation questions and answers

 

[droidx]

Reserved for installation pictures

 

[Gtx Gaming]

8KW SunSynk + 8x 545w jinko Solar panels + 10kw hubble new one with 10 year warranty unlimted cycles.

 

[Benedict A55h0le not]

Will you be paying the extra fee for registration or do the registration yourself? Do you know how to do the registration yourself? Is it worth trying to register it yourself?

 

[droidx]

8KW SunSynk + 8x 545w jinko Solar panels + 10kw hubble new one with 10 year warranty unlimted cycles.

This gives a 4.36kwp array, how will this work with the 8kw inverter, would a 5kw inverter not handle that array in the same way? I understand the hubble has a 1c discharge, which would then take advantage of the 8kw inverter and I could have more on essentials. This is an option. Since my total usage is 10kw, it will be a good margin of safety. Do you know of an installer in Cape Town working with both products, I could get a quote.

 

[droidx]

Will you be paying the extra fee for registration or do the registration yourself? Do you know how to do the registration yourself? Is it worth trying to register it yourself?

The one quotation I got has a fee for doing this on your behalf. I am following @DawieZA's thread to see his experience in doing it himself with the support of the installer. I do a have a quote from his installer as well.
So in short, I am still figuring this one out.

 

[Gtx Gaming]

This gives a 4.36kwp array, how will this work with the 8kw inverter, would a 5kw inverter not handle that array in the same way? I understand the hubble has a 1c discharge, which would then take advantage of the 8kw inverter and I could have more on essentials. This is an option. Since my total usage is 10kw, it will be a good margin of safety. Do you know of an installer in Cape Town working with both products, I could get a quote.

The Array power has nothing to with KW of the Inverter , the MPPT handles the voltage of solar coming in to inverter. I think this inverter takes max 5000 to 6000watt of solar. You will never get the full rated solar out of your panels.

This inverter can blend solar and battery power so you can use the maximum power of the inverter if you need to use it.

5Kw is probably fine, problem is when wife has airfyer running and aircons, then 5kw might struggle.

10Kw battery is also bit overkill but it gives basically full day of regular usage, even you dont get sunlight to charge the batteries, but you will proabbly get some sort of sunlight

 

[droidx]

The Array power has nothing to with KW of the Inverter , the MPPT handles the voltage of solar coming in to inverter. I think this inverter takes max 5000 to 6000watt of solar. You will never get the full rated solar out of your panels.

This inverter can blend solar and battery power so you can use the maximum power of the inverter if you need to use it.

5Kw is probably fine, problem is when wife has airfyer running and aircons, then 5kw might struggle.

10Kw battery is also bit overkill but it gives basically full day of regular usage, even you dont get sunlight to charge the batteries, but you will proabbly get some sort of sunlight

Thanks, I get that, but the solar at no point will be able to supply at the full power of the inverter.
But the blending of power with the battery to cover peak demand up to 8kw makes sense.

On the 5kw struggling, am I correct in saying that when the grid is available, the inverter will supplement with power from the grid. The problem will arise when the grid is not available and the inverter will trip?

 

[droidx]

Any comments on this combo, specifically the battery?

8KW DEYE CYCLONE M10

THIS PACK INCLUDES: 1 x DEYE 8KW INVERTER 10 x 545W PANELS 100m x 6mm SOLAR CABLE 10 x MC4 CONNECTORS 1 x PVC2 COMBINER 1 x AC PROTECTION + CHANGEOVER 1 x CYCLONE M10 BATTERY COMPLETE MOUNTING SYSTEM FOR TILE/IBR ROOF

www.solarwaysuppliers.co.za

 

[abudabi]

Any comments on this combo, specifically the battery?

8KW DEYE CYCLONE M10

THIS PACK INCLUDES: 1 x DEYE 8KW INVERTER 10 x 545W PANELS 100m x 6mm SOLAR CABLE 10 x MC4 CONNECTORS 1 x PVC2 COMBINER 1 x AC PROTECTION + CHANGEOVER 1 x CYCLONE M10 BATTERY COMPLETE MOUNTING SYSTEM FOR TILE/IBR ROOF

www.solarwaysuppliers.co.za

I saw that yesterday and was also wondering about the battery

 

[Katelknaap]

I'm also in the process of looking at expanding my current backup system (5kw Sunsynk with 5kwh Hubble battery) with solar panels.

I found a very useful, and more importantly, free tool that you might find helpful. Have a look at Opensolar's website (they have an app, but it's just easier on a computer). You register and can then start playing around with the design of your system at your exact location. U add the exact inverter, batteries and the panels and the site then gives you all kinds of interesting and useful info on what your system could potentially produce. You can even add in your local electricity tariff and then it calculates your return period, etc.

Just beware, it's a deep rabbit hole once u start playing around! U can either follow the tutorials available or just play around until u know what u are doing. It takes a while, but it's not very difficult.

I also have only East & West roofs available. Interestingly, I put say 6 panels on my NW facing roof and the same on my neighbors lovely North facing roof. Surprisingly there was not much difference in the production figures provided between the 2 "systems".

Home

OpenSolar connects homeowners, solar professionals, and partners with free software to design, sell, and manage fast, accurate solar projects.

www.opensolar.com

 

[B-1]

Thanks, I get that, but the solar at no point will be able to supply at the full power of the inverter.
But the blending of power with the battery to cover peak demand up to 8kw makes sense.

On the 5kw struggling, am I correct in saying that when the grid is available, the inverter will supplement with power from the grid. The problem will arise when the grid is not available and the inverter will trip?

The 5kw one can do up to 10kw but only for 10 seconds. Its rated for 5.5kw nominal but some run it over that but they may change the firmware if they haven't already.

You can probably get away with with the 5kw but looking at all your appliances you are going to have to constantly manage it or its going to trip on you quite often. If you can definitely swing for the 8kw or know you will likely have to add another 5kw in future so you don't have to constantly ask what's on at the moment.

 

[rh1]

I have 3 fridges, 3 pumps( 900w, 2x 450w), 1 x pool pump, 1 x 150litre geyser, 2 xAircons, 3 tvs, 1 x desktop pc (always on).

I have 10 x 460w panels, 2 x 5.5kWh batteries and a 8kW Sunsynk inverter. No issues so far. The bigger inverter allows me to have kettle, microwave and oven on the same time. These tend to use the most watts.

 

[rh1]

To add on, load shedding has dissapeared at my home. My panels are east and west, 5 per side. Basically only use 5 at the time except at noon, when all 10 are generating. Still manage to charge all my batteries before lunch.

My batteries are 50% in the morning, except where I was using the aircon through the night, when it can go as low as 38%.

Really overcast days is where I struggle. I would like to add at least 3 panels facing east to add to the morning generation.

 

[droidx]

I'm also in the process of looking at expanding my current backup system (5kw Sunsynk with 5kwh Hubble battery) with solar panels.

I found a very useful, and more importantly, free tool that you might find helpful. Have a look at Opensolar's website (they have an app, but it's just easier on a computer). You register and can then start playing around with the design of your system at your exact location. U add the exact inverter, batteries and the panels and the site then gives you all kinds of interesting and useful info on what your system could potentially produce. You can even add in your local electricity tariff and then it calculates your return period, etc.

Just beware, it's a deep rabbit hole once u start playing around! U can either follow the tutorials available or just play around until u know what u are doing. It takes a while, but it's not very difficult.

I also have only East & West roofs available. Interestingly, I put say 6 panels on my NW facing roof and the same on my neighbors lovely North facing roof. Surprisingly there was not much difference in the production figures provided between the 2 "systems".

Home

OpenSolar connects homeowners, solar professionals, and partners with free software to design, sell, and manage fast, accurate solar projects.

www.opensolar.com

Thanks very cool website and a deep rabbit hole indeed haha.
I’ve played around, I’ll achieve same results with 8kw and 5kw inverters in terms of savings, whereas the 8kw will give me the flexibility of less management of load. Both meet my generation requirements though.

Very interesting, didn’t have time to play much more with different orientations and reducing panel array, but will definitely do so. Also didn’t play too much with input costs just focused on system.

 

[droidx]

The 5kw one can do up to 10kw but only for 10 seconds. Its rated for 5.5kw nominal but some run it over that but they may change the firmware if they haven't already.

You can probably get away with with the 5kw but looking at all your appliances you are going to have to constantly manage it or its going to trip on you quite often. If you can definitely swing for the 8kw or know you will likely have to add another 5kw in future so you don't have to constantly ask what's on at the moment.

I hear you. The flexibility with larger battery bank and inverter will be useful. I’ll also probably regret it if I didn’t do it.

Any opinions on the Deye/Dyness combo.
The Sunsynk is just way too much more for a similar system and by my calculations and your explanation, I don’t need the bigger array.

 

[droidx]

I have 3 fridges, 3 pumps( 900w, 2x 450w), 1 x pool pump, 1 x 150litre geyser, 2 xAircons, 3 tvs, 1 x desktop pc (always on).

I have 10 x 460w panels, 2 x 5.5kWh batteries and a 8kW Sunsynk inverter. No issues so far. The bigger inverter allows me to have kettle, microwave and oven on the same time. These tend to use the most watts.

Thanks for this, your use case seems similar to mine.
It would be good not to be worried about consecutive load, where I would have to with 5kw. Easy enough for me to manage but will likely frustrate my wife.

I’m now leaning towards quotation 3. Does this look reasonable?
Now to arrange some visits.

Multi quote not working on Tapatalk, apologies for multiple posts.