Beating Load Shedding with some ROI

[PRP]

Hi Everyone

Long time lurker driven to action by Stage6 + Unhappy Wife

Looking for advice as I am sure many other people have walked up and down the spec line as I have.

We use ~30kwh per day (Single Geyser, Oven, Pool Pump, Gas Hob, General Appliances)

I have no plans to invest R150K+ or more like others have with lots of storage, my intention is to "Beat Load Shedding" but get some payback for the system. 

- Started off considering a 3KW system for ~R20K (3KW Inverter, 3KW Storage) can only do very basics (no appliances)

- Moving to 5KW jumps to ~R40K (Kodak 5KW + 5Kwh Battery - Say Hubble for 1C) - Here I can run some appliances.  If I add panels will be tricky to feed the high consumers (Stove, Geyser, etc)

My logic therefore, likely flawed is as follows:

I see the R40K as a investment in keeping a certain quality of life, so they money is spent and gone...

Am I crazy in thinking I should rather spend R10K Extra on the inverter for a True Sunsynk Hybrid and add R30K worth of Panels in order to "payback" this additional R40K over the next few years. If I can save ~R1200 per month by cutting 300-400Kwh off my bill (on the higher Tariff Tier) then I can pay off this additional in 3-4 years?

Battery will just be for Load Shedding...

If anyone  been down this road please let me know if I am nuts or thinking soundly. 

Cheers

[Brendonvdh]

Hey PRP

I been stuck in this rabbit hole for the last week already. The more you look the more complicated it gets. 

I average about 13kw/day usage

I started with plan for a budget 5kw backup system, best price I could find was about R45K installed, and was battling to justify the cost. 

In the end I have decided to go for a 3kW system, about R25K installed, which will cover our lights, internet, TV which ticks enough boxes for me.

You use a lot more electricity than me so will get a ROI sooner

A system that can save you 300-400kw/month is probably closer R100K I think? so ROI like 7 years @ R1200/month (by my very crude calcs.)

[Kalahari Meerkat]

We used to use 30kWh/day, after a good look and kicking that dual Xeon machine off and only switching it on once or twice a month when really necessary for 2 or 3 hours during sunshine and generally not being wasteful we are probably around 16 to 20kWh/day these days... I don't think you need a Sunsynk, we have a 5kW Sunsynk, but I believe some of the Axpert type inverters can also mix from grid to make up the possible shortfall from solar/battery, some of the other members around may be able to confirm which inverter you should look at, certainly you should add solar and reduce your Eskom/Municipal bills electric charges this way around and enjoy the benefits of being somewhat independent from the grid...

 

[PRP]

36 minutes ago, Brendonvdh said:

Hey PRP

I been stuck in this rabbit hole for the last week already. The more you look the more complicated it gets. 

I average about 13kw/day usage

I started with plan for a budget 5kw backup system, best price I could find was about R45K installed, and was battling to justify the cost. 

In the end I have decided to go for a 3kW system, about R25K installed, which will cover our lights, internet, TV which ticks enough boxes for me.

You use a lot more electricity than me so will get a ROI sooner

A system that can save you 300-400kw/month is probably closer R100K I think? so ROI like 7 years @ R1200/month (by my very crude calcs.)

I can do the install myself so that should save a bit. I didn’t expect R100k, was thinking of just adding 4000W of solar but I could be missing lots of hidden costs! I have been going in circles for a while, going up and down the spec curve. Maybe R25k is better and just learn to live carefull, changing over the plugs to mains after every shed. 

34 minutes ago, Kalahari Meerkat said:

We used to use 30kWh/day, after a good look and kicking that dual Xeon machine off and only switching it on once or twice a month when really necessary for 2 or 3 hours during sunshine and generally not being wasteful we are probably around 16 to 20kWh/day these days... I don't think you need a Sunsynk, we have a 5kW Sunsynk, but I believe some of the Axpert type inverters can also mix from grid to make up the possible shortfall from solar/battery, some of the other members around may be able to confirm which inverter you should look at, certainly you should add solar and reduce your Eskom/Municipal bills electric charges this way around and enjoy the benefits of being somewhat independent from the grid...

 

The reason for the sunsynk was to be able to easily push back excess solar during the day to the non essential loads, not really for the AC+PV blending. To wire the geyser into the output of the inverter I would need to jump to 7.2kw Kodak for R18k and then worry about a smart switch on the geyser opens  during load shedding.
 

I might be missing all sorts of other costs or over estimating the savings. I hope someone else has been in and out of this rabbit role like me and can give me some results after their install.  

[De0n19]

I can say that running a 5kw sunsynk with 6.5kwp of panels and a single pylontech 3.55kwh battery is currently saving me about R20 000 per year in electricity. Battery is only used for lighting, tv, internet, alarm, electric fence, gate motor and can supply power for 6 hours during the night. A sunsynk or deye inverter with minimal battery is allot cheaper than a cheaper inverter and then being forced to spend money on lots more battery storage.

[Bobster.]

On 2022/09/19 at 2:34 PM, PRP said:

Hi Everyone

Long time lurker driven to action by Stage6 + Unhappy Wife

Looking for advice as I am sure many other people have walked up and down the spec line as I have.

We use ~30kwh per day (Single Geyser, Oven, Pool Pump, Gas Hob, General Appliances)

I have no plans to invest R150K+ or more like others have with lots of storage, my intention is to "Beat Load Shedding" but get some payback for the system. 

- Started off considering a 3KW system for ~R20K (3KW Inverter, 3KW Storage) can only do very basics (no appliances)

- Moving to 5KW jumps to ~R40K (Kodak 5KW + 5Kwh Battery - Say Hubble for 1C) - Here I can run some appliances.  If I add panels will be tricky to feed the high consumers (Stove, Geyser, etc)

My logic therefore, likely flawed is as follows:

I see the R40K as a investment in keeping a certain quality of life, so they money is spent and gone...

Am I crazy in thinking I should rather spend R10K Extra on the inverter for a True Sunsynk Hybrid and add R30K worth of Panels in order to "payback" this additional R40K over the next few years. If I can save ~R1200 per month by cutting 300-400Kwh off my bill (on the higher Tariff Tier) then I can pay off this additional in 3-4 years?

Battery will just be for Load Shedding...

If anyone  been down this road please let me know if I am nuts or thinking soundly. 

Cheers

Firstly, try and see if you can get that 30kwh per day down. Try to analyse where it is all going and then see where you can cut down. Maybe (for a common EG) you are running your geyser unnecessarily hot.

I say this because:
1) I think most people can make a savings on their bill without serious compromise
2) To maximise the PV system's benefits, you will need to do as much "heavy lifting" as possible during the day to make the most of the free power
3) If you can reduce that figure you can either reduce the size of your PV system or back up more with the same system.

You won't save unless you can reduce your consumption and/or have PV. If you carry on as usual and don't have PV, you are storing power for later use, and because of losses in the system, you will actually pay a little more. Once you have PV you get some free power in the daylight hours, and you can charge your battery if there is sunshine but no grid.

This is a long term investment. When I bought my system (I don't have the skills to do my own install), I figured a 7 year payback. I don't think that anymore. That doesn't mean I have regrets, just that I have had to adjust my expectations. This is doing the simple accounting of what I didn't pay on the meter. There are other benefits that are harder to put a price on: always having the lights on, always being able to open the garage, not losing the contents of the freezers, always having the security systems, always being able to read, use a computer, or watch TV, not having to check load shedding schedules when inviting friends around, etc. These are all valuable, even if harder to express as rands and cents.

Finally, check what tariff you are on. I recently heard stories about people who have installed PV and didn't see the expected nice round number on their bill under the heading electricity. They thought that Eskom was punishing PV users, but the reality is that they were on a tariff which had a fixed component per month for the connection and the costs that go with that, and that doesn't fall away even if your consumption from grid is zeo.

[Kalahari Meerkat]

On 2022/09/19 at 6:19 PM, PRP said:

I would need to jump to 7.2kw Kodak for R18k and then worry about a smart switch

Ok, that's not a bad option and the smart switch can merely be a relay that allows the HWC to run, when the grid is available, in other words a 240V relay that can switch, lets say, 40A 240V AC on its contacts, this, wired with Normally Open contacts in line with the HWC and the coil from the relay is energised by 240V before the inverter, so if the grid is there the contacts are closed, else no juice/connection to HWC...

Agree with @Bobster. you should look at reducing the consumption and move the timing of the consumption during solar power producing periods as well, we run the dishwasher late morning, early afternoon, it never uses battery to do this, same with washing machine, we never run it in the evening etc.

[PRP]

Thanks for all the suggestions. Difficult to see where I could reduce the consumption as a whole vs moving when it is consumed. 

We have a 200L 4KW Geyser which is set to 65DegC. With Solar will try schedule one the heating of this ( considering a reduction to 2/3KW element) during the peak solar time (after mornings showers) and then accept that I will need to still do one heating early morning before morning showers.

Other than that all lights are LED, only a single Inverter Fridge/Freezer and appliances are pretty new with good energy ratings. We dont have a tumble dryer or big PCs. 

I am with Eskom Direct so the ~R500 base network charge wont go away. Total bill is ~R3000 (R500 Network, R1100 - 600Kwh @ cheap rate, R1200 R400Kwh @ higher tariff). 

I have upped the budget to ~R100K now and see R30-40K as a life style investment (security, convenience, etc) and the R60-70K as a solar investment which I hope to payback over 5 years if I can just save 400Kwh a month on the higher tariff (4Kw solar array hoping to get 14Kwh per day)

 

[Kalahari Meerkat]

18 minutes ago, PRP said:

that I will need to still do one heating early morning before morning showers.

if you have evening showers + morning showers, probably/possibly, but going insulation berserk on this animal to reduce the losses to the environment could be a relatively inexpensive way of reducing power consumption... we used to switch on the 3kW 150 or 200l, not sure what it was, HWC for 30 to 45 minutes and then the water was hot enough for a warm shower, otherwise the HWC was off, now we have a 100l solar HWC, no electricity, only the 10 or 12 evacuated glass tubes doing their thing, at the depths of winter, you should probably shower not later than 7PM and no early morning showers, but this time of year, already the water in the morning is warm enough for a warm, not hot, shower and even by 9PM its still plenty warm as well...

Based on your LED lights etc. I suspect most of your power is subsidising the HWC... this, with some planned insulation installed could save you some dosh...

[Bobster.]

23 minutes ago, PRP said:

Thanks for all the suggestions. Difficult to see where I could reduce the consumption as a whole vs moving when it is consumed. 

We have a 200L 4KW Geyser which is set to 65DegC. With Solar will try schedule one the heating of this ( considering a reduction to 2/3KW element) during the peak solar time (after mornings showers) and then accept that I will need to still do one heating early morning before morning showers.

Other than that all lights are LED, only a single Inverter Fridge/Freezer and appliances are pretty new with good energy ratings. We dont have a tumble dryer or big PCs.

usually the big users in a house are the geyser and the stove. The trick with anything involving the sun is to make hay whilst the sun shines  , and to make as much hay as you can.

in my case the total usage was down to 1/2 yours before we converted to PV. After the conversion I got access to a graphing tool that would show me what was used over a 24 hour period. That was when I could start moving loads around using timer switches (which I already had) and we could start making some lifestyle choices to maximise the system - like controlling when the water heating runs, like (as already mentioned), using the dishwasher during daylight hours (not at night. That is really unacceptable. Just no). It would have been useful to have this sort of information ahead of the install, though once you get that information, you can react to it quite quickly.

[PRP]

I hear you about the Geyser, I will try add a blanket. There are 4 of us, two kids shower once a day and the adults 3 times on average (two morning sometimes at night as well) Also have a 750W pool pump which runs for a 2 hours in Winter and around 4-6 in summer.  We dont use the Oven that much after getting an air fryer which cooks in 1/2 the time. 

Having the information about the loads upfront is great but in the end I see the solution as the same, ie Solar with main loads during peak production. I am starting off with what I see as a minimum battery 5Kwh and min solar (~4kw from 7 panels on a single string) and after I have some solid results I can plot the way forward. 

I am hoping I can save the R1200 a month with just this and not need extra storage + solar, but time will tell.

From reading here lots it seems everyone under estimate the solar and storage requirements and add more soon after install.  I am really hoping my difference is I am not trying to cut my bill totally, just drop the 300-400kw from the higher tier tariff. 

[kombiman]

Hi guys, 

am getting by with 2 mecer lobo inverters and hubble\halo's at the mo, but am\have been considering a bigger installation, and, as has been said here, the more you read up\look into it, the more complicated, and deeper the hole goes. 

So my investment right now should last a few years, (touch wood), that nothing blows up, but, I have the space for Solar PV, and would like to get a smaller idea of what I need. 
How DO you work out your usage per day, if I may ask?  The OP said numbers like 30kwh per day. Can one work this out based on how many units I use in a 24 hour period? accurately?

thanks in advance, and apologies for sound worse than a noob, but I struggle to grasp this stuff at the best of times.

Alan

 

Edited September 27, 2022 by kombiman
spelling

[Paulcupine]

Om te meet is om te weet.  I agree with others here that you should measure before you spend.  I ran one of those Efergy meters in my house for about six months before installing anything.  Once you have a handle on your consumption - what's what, what can change and what cannot - you will be far better placed to buy appropriately.

While one could go for a system that is backup power only with grid charging, remember that you then only have costs.  Batteries don't save you money and every kWh that goes into them you only get part of a kWh back.  PV panels are both the cheapest part of your system and the only part that makes you money. 

The 2kW worth of panels I put in a little over three years ago have generated 10MWh of energy.  They have already paid for themselves and part way for the Fronius they're connected to.  A little over two years ago I added another 2kW of panels and those have already generated around 7MWh.  Once the panels have paid for themselves, they start paying for the rest of your system - at least that's how I see it.

[PRP]

1 hour ago, kombiman said:

Hi guys, 

am getting by with 2 mecer lobo inverters and hubble\halo's at the mo, but am\have been considering a bigger installation, and, as has been said here, the more you read up\look into it, the more complicated, and deeper the hole goes. 

So my investment right now should last a few years, (touch wood), that nothing blows up, but, I have the space for Solar PV, and would like to get a smaller idea of what I need. 
How DO you work out your usage per day, if I may ask?  The OP said numbers like 30kwh per day. Can one work this out based on how many units I use in a 24 hour period? accurately?

thanks in advance, and apologies for sound worse than a noob, but I struggle to grasp this stuff at the best of times.

Alan

 

 

For me I just took my monthly usage and divided by 30 to get an estimate. 

53 minutes ago, Paulcupine said:

Om te meet is om te weet.  I agree with others here that you should measure before you spend.  I ran one of those Efergy meters in my house for about six months before installing anything.  Once you have a handle on your consumption - what's what, what can change and what cannot - you will be far better placed to buy appropriately.

While one could go for a system that is backup power only with grid charging, remember that you then only have costs.  Batteries don't save you money and every kWh that goes into them you only get part of a kWh back.  PV panels are both the cheapest part of your system and the only part that makes you money. 

The 2kW worth of panels I put in a little over three years ago have generated 10MWh of energy.  They have already paid for themselves and part way for the Fronius they're connected to.  A little over two years ago I added another 2kW of panels and those have already generated around 7MWh.  Once the panels have paid for themselves, they start paying for the rest of your system - at least that's how I see it.

I hear you, knowing exactly what consumes when helps to plan. I feel like I already have my heart set on the 5Kw SunSynk. It just makes my life so much simpler with the Geyser, Pool Pump and Stove on the non essentials being fed by excess PV.  I see 5KW as the min battery needed to get by with a 4 hour load shed slot. I will put the panels up at the same time as the rest of the system given the price to install the panels it makes sense to fully utilize one roof I have and put ~4KW in one shot. 

Then I can start save some money already and monitor and see how to tweak and optimize the system potentially with more storage in the future, more PV on a second roof, etc. 

Thanks to everyone for all the guidance, I have the Inverter and Panel ( 7 x 545W) done, still just going back and forth with the battery... 

[kombiman]

@PRP, Yes, this I can do, and can get my numbers, or an average for 24 hours, but, what is that telling me? 3 units in 24 hours means, what was my usage? 

 

[GreenFields]

3 hours ago, PRP said:

am starting off with what I see as a minimum battery 5Kwh and min solar (~4kw from 7 panels on a single string)

56 minutes ago, PRP said:

Thanks to everyone for all the guidance, I have the Inverter and Panel ( 7 x 545W) done, still just going back and forth with the battery... 

I'm just trying to get behind the logic of 7x545W panels on a single string. The Sunsynk/Deye 5kW has a limit of 6500kW of PV, but it's spread over 2 MPPT inputs. Speaking under correction, but I'm thinking it would be better to go for max 5x545W on each MPPT to limit the clipping of the output of nearly 4kW of panels to just 2.5kW. I understand the logic of spreading production over the whole day at the expense of peak production, but is one here not overloading the first MPPT, and then if you're forced to divert panels to the other MPPT, perhaps getting too little voltage with just 2 or 3 panels?

 

 

[Scorp007]

I find the comments and advice to bloody interesting out of a diverse point of view. Further to see how systems vary from R25 000 to over R200th.

Then to see how we want to fill our wants and not our needs. At times like my one friend he is deciding for 8 years on something and 5kw system seems too small for his 6 fridges and and and... He is trying to get along with a 1.2kw non sine wave that cannot even help to keep a fridge going. So many frustrations over the years because he hopes to find the best system with great ROI.Then blending high MPPTs are great but not that you cannot get along with an older spec that has about 25% headroom above the highest load.

So you want to save get a cheap system. Nothing says you cannot split your loads between more than 1 inverter even if they cannot operate in parallel. Yes it does cost more as each one will need it's own battery. Starting you can already save during day time. Many might say how?

Take this as an eexample 3kVA Axpert clone.  1.6kw panels that during the peak sun period uses 1.3kw towards load from PV. If the load is higher the battery adds.  In the periods that the load is low the battery gets charged. Come LS you have lights, WiFi and real eessential. This satisfies the need and not the want. This small system even heats my geyser. Yes unlike a lot of people I don't mind drawing from the grid for those gadgets that draw too much from the batteries, PV even inverter. Charging is mostly from PV and the grid is there if it is needed for LS periods.

One can always after the 1st 3kw unit add another or sell and buy a larger unit or get a 2nd one. Not all can buy a Synsynk and start with an inverter which is actually a control system to manage everything.

The sooner one starts the quicker one can learn how to manage between various loads and size of batteries if one goes the lithium route and start small.

Sorry if I mentioned what has been stated as I did not read from the OP.

 

[PRP]

9 minutes ago, GreenFields said:

I'm just trying to get behind the logic of 7x545W panels on a single string. The Sunsynk/Deye 5kW has a limit of 6500kW of PV, but it's spread over 2 MPPT inputs. Speaking under correction, but I'm thinking it would be better to go for max 5x545W on each MPPT to limit the clipping of the output of nearly 4kW of panels to just 2.5kW. I understand the logic of spreading production over the whole day at the expense of peak production, but is one here not overloading the first MPPT, and then if you're forced to divert panels to the other MPPT, perhaps getting too little voltage with just 2 or 3 panels?

 

 

My logic here is the panel install is more than 2 x one panel cost so I thought I would maximize one roof  and put as much as I can on one string. The cost of 5 panel install vs 7 is so close. 

If I put 7 panels on one string can I not just add 5 on the other string IF I upgrade in the future? I thought the total power was shared between the two MPPT so no issue to have 4kw on one and 2.5kw on another. My roof is at ~20 deg slope, in JHB and is around 10 Deg off North so I also assume I wont get the full ~4KW anyway. 

11 minutes ago, Scorp007 said:

I find the comments and advice to bloody interesting out of a diverse point of view. Further to see how systems vary from R25 000 to over R200th.

Then to see how we want to fill our wants and not our needs. At times like my one friend he is deciding for 8 years on something and 5kw system seems too small for his 6 fridges and and and... He is trying to get along with a 1.2kw non sine wave that cannot even help to keep a fridge going. So many frustrations over the years because he hopes to find the best system with great ROI.Then blending high MPPTs are great but not that you cannot get along with an older spec that has about 25% headroom above the highest load.

So you want to save get a cheap system. Nothing says you cannot split your loads between more than 1 inverter even if they cannot operate in parallel. Yes it does cost more as each one will need it's own battery. Starting you can already save during day time. Many might say how?

Take this as an eexample 3kVA Axpert clone.  1.6kw panels that during the peak sun period uses 1.3kw towards load from PV. If the load is higher the battery adds.  In the periods that the load is low the battery gets charged. Come LS you have lights, WiFi and real eessential. This satisfies the need and not the want. This small system even heats my geyser. Yes unlike a lot of people I don't mind drawing from the grid for those gadgets that draw too much from the batteries, PV even inverter. Charging is mostly from PV and the grid is there if it is needed for LS periods.

One can always after the 1st 3kw unit add another or sell and buy a larger unit or get a 2nd one. Not all can buy a Synsynk and start with an inverter which is actually a control system to manage everything.

The sooner one starts the quicker one can learn how to manage between various loads and size of batteries if one goes the lithium route and start small.

Sorry if I mentioned what has been stated as I did not read from the OP.

 

Fully agree. Very difficult to pull ones self out of the rabbit hole and reinstate logic once you are in deep and emotionally invested.  Everyones desiresand essentials are different so I guess this is why we see such a varfiety of systems on here. 

[Peter V]

5 hours ago, PRP said:

We have a 200L 4KW Geyser which is set to 65DegC. With Solar will try schedule one the heating of this ( considering a reduction to 2/3KW element) during the peak solar time (after mornings showers) and then accept that I will need to still do one heating early morning before morning showers.

Your first big win is to install solar water heating. Vacuum tube is preferable. If you are fortunate as I am being coastal, you can install a thermo syphon unit but if inland and prone to sub zero night time temperatures an indirect system will cost a bit more. It may be argued that using excess PV during daytime can be used but this does not heat water at 0500 on a cold winter night when you need a hot shower before going to work. Typical solar geysers have a 2 kW element installed and in my case it only needs to run for an hour on no more than 30 or so days a year.

[Scorp007]

Sorry but as much as a solar geyser saves you you can get stuck with not enough water after sunset. Very few people that have had a solar geyser and had to change tubes and end up with an inverter would again consider it for heating the geyser. PV is just a more efficient system. So many members say they have excess power and it would be less if the PV system is a Sunsynk that can ensure hot water.

@PRP

Yes you can do the 5 and 7 in 2 strings then that is done and feed each string to a MPPT. The MPPT work independently from each other to combine the power available. My comment was more of a general input and not on what you have in mind.

There are a number of appliances that can run in day time from a 3kVA as I do. Heating water for washing could be a no no. By choice we use cold water and our machine can actually run from 1x270W panel and 1 x 100Ah 12V battery without problems. When not cooking and only heating I also use my micro from PV and battery. We do use gas for boiling water and not a AC kettle.

Edited September 27, 2022 by Scorp007

[GreenFields]

On 2022/09/19 at 2:34 PM, PRP said:

Hi Everyone

Long time lurker driven to action by Stage6 + Unhappy Wife

Looking for advice as I am sure many other people have walked up and down the spec line as I have.

We use ~30kwh per day (Single Geyser, Oven, Pool Pump, Gas Hob, General Appliances)

I have no plans to invest R150K+ or more like others have with lots of storage, my intention is to "Beat Load Shedding" but get some payback for the system. 

- Started off considering a 3KW system for ~R20K (3KW Inverter, 3KW Storage) can only do very basics (no appliances)

- Moving to 5KW jumps to ~R40K (Kodak 5KW + 5Kwh Battery - Say Hubble for 1C) - Here I can run some appliances.  If I add panels will be tricky to feed the high consumers (Stove, Geyser, etc)

My logic therefore, likely flawed is as follows:

I see the R40K as a investment in keeping a certain quality of life, so they money is spent and gone...

Am I crazy in thinking I should rather spend R10K Extra on the inverter for a True Sunsynk Hybrid and add R30K worth of Panels in order to "payback" this additional R40K over the next few years. If I can save ~R1200 per month by cutting 300-400Kwh off my bill (on the higher Tariff Tier) then I can pay off this additional in 3-4 years?

Battery will just be for Load Shedding...

If anyone  been down this road please let me know if I am nuts or thinking soundly. 

Cheers

Back to the OP: I've written some posts with this line of thinking in the past. So at the risk of bleating the same humdrum:

Yes, I think it makes sense to split the costs for a solar setup in this way, depending on your goals. My beloved analogy is that in the investment world you get pure investment products, pure insurance products, and then some that combine insurance and investment. Which part of your hybrid solar would be the equivalent of investment (solar panels, MPPT and half of the inverter circuitry), and which are an insurance against outages (charger, batteries, and the other half of the inverter circuitry). Decide how much of each you want. When it comes to the battery backup, don't only think in terms of lifstyle or convenience, but that you're protecting valuable assets against power surges, with continued security, maybe protecting against loss of income, against the cost of pool restorations, marriage counselling and divorce proceedings, etc.

For the panels, I think if in your mind you take R30K of panels and half the cost of a Sunsynk, say just 2500-3000W of panels on the 1st MPPT to start off with, that should get close to eliminating that high-level usage with best returns, for limited expense, if you're not going all out with batteries.

Edited September 27, 2022 by GreenFields

[PRP]

5 minutes ago, GreenFields said:

Back to the OP: I've written some posts with this line of thinking in the past. So at the risk of bleating the same humdrum:

Yes, I think it makes sense to split the costs for a solar setup in this way, depending on your goals. My beloved analogy is that in the investment world you get pure investment products, pure insurance products, and then some that combine insurance and investment. Which part of your hybrid solar would be the equivalent of investment (solar panels, MPPT and half of the inverter circuitry), and which are an insurance against outages (charger, batteries, and the other half of the inverter circuitry). Decide how much of each you want. When it comes to the battery backup, don't only think in terms of lifstyle or convenience, but that you're protecting valuable assets against power surges, with continued security, maybe protecting against loss of income, against the cost of pool restorations, marriage counselling and divorce proceedings, etc.

For the panels, I think if in your mind you take R30K of panels and half the cost of a Sunsynk, say just 2500W of panels on the 1st MPPT to start off with, that should get close to eliminating that high-level usage. But if you're not going the whole hog with batteries and exceptional measures to push loads to the daytime, I think that 5kW of panels could in your case be wasted.

Fantastic explanation and I love the Red part, properly laughed!!

Of course part of the investment is a change of habits, daytime running for dishwasher, washing machine, pool pump and Geyser (Dropping to 2KW element + Geysewise)

My idea is to heat the water up in the day to as much as the Geyserwise will allow (65Deg?) to use it as an "Energy Store" and then only heat it up to 50DegC during the night for the morning showers. 

[Scorp007]

1 hour ago, PRP said:

Fantastic explanation and I love the Red part, properly laughed!!

Of course part of the investment is a change of habits, daytime running for dishwasher, washing machine, pool pump and Geyser (Dropping to 2KW element + Geysewise)

My idea is to heat the water up in the day to as much as the Geyserwise will allow (65Deg?) to use it as an "Energy Store" and then only heat it up to 50DegC during the night for the morning showers. 

Not sure what took place but I am sure a read something that you wanted to get rid of the high rate charged and hoping to save R1200.

Cannot comment on that without knowing what time of day that is. What I can comment and assist is the hope of getting 4kW from your 7x545W panels. In Gauteng we get 80-85% of the PV rating quoted at 1000W/m2. At this ideal condition(100%) it works out to 3815W. Converting this value at 80% it gives 3052W. The achievable PV per day if you don't have any wasted power is 3.052x5=15.26kWh per day. You can rework this based on your price per kWh during the sun period.

Yes the angle comes into play and so does clouds. This is provided as a guidance. Yes some days you might get 3.052x6=18.312kWh but there will also be days you will only get 10% of the normal you get in full sun for the whole day.

[PRP]

7 minutes ago, Scorp007 said:

Not sure what took place but I am sure a read something that you wanted to get rid of the high rate charged and hoping to save R1200.

Cannot comment on that without knowing what time of day that is. What I can comment and assist is the hope of getting 4kW from your 7x545W panels. In Gauteng we get 80-85% of the PV rating quoted at 1000W/m2. At this ideal condition(100%) it works out to 3815W. Converting this value at 80% it gives 3052W. The achievable PV per day if you don't have any wasted power is 3.052x5=15.26kWh per day. You can rework this based on your price per kWh during the sun period.

Yes the angle comes into play and so does clouds. This is provided as a guidance. Yes some days you might get 3.052x6=18.312kWh but there will also be days you will only get 10% of the normal you get in full sun for the whole day.

Thanks for the assistance. The higher tariff isn’t based on time of use but rather anything over 600kwh per month. 300-400kwh means 10-13kwh per day so I am hoping a 4kw array will cover this on average per day. 

[Scorp007]

1 hour ago, PRP said:

Thanks for the assistance. The higher tariff isn’t based on time of use but rather anything over 600kwh per month. 300-400kwh means 10-13kwh per day so I am hoping a 4kw array will cover this on average per day. 

OK now we are on the same page. I never knew Eskom price units in the same way as Munics. I have always been jealous when I see their low rates per unit but also happy to not pay their daily charges just for having power.

Based on my 15kwh per day if you can manage to use all your power generated and stored you should meet your target.

I use 100% of my generation and I can just say my system over 39 months have generated 4.04kWh/1kW of panels installed in Gauteng. It would be a bit higher but I generate no power during LS unless I'm at home during 4hr LS over weekends while sun is shining.