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Hi all.  

Very new here and need some advise please.

I have no previous experience with Solar, except having solar geysers installed.  I am based in Cape Town

So here goes.  

My household (4 adults and 2 teens) utilizes approximately 40KW or Units (Per Prepaid meter) a day.  Most of the usage around 75% or 30 units (as per my crude hourly calcs and recording) takes place during the day from about 7am to 6pm.  Thereafter it consumes around 10 units for the rest of the evening until 6am the next morning.  

This however includes topping up the solar geyser temperature as well.

So as my parents live with me we have 2 Fridges and freezers, 1 x Chest Freezer, 2 x Geysers (one 150L converted to Solar other one 100L running off eskom with Geyserwise installed running for 2 hrs a day max).

Also, have a 0.75KW pool pump running for 6 hours a day (in winter) (8 hours or more in summer)

All lighting upgraded to LED. Trying to be as energy efficient as possible. 

So, with this in mind, and the very steep initial cost to setup the solar system, I have been thinking of going for a system (initially) without using Batteries (as these are quite expensive).

ie. System which will generate and use power generated by the Solar Panels during the day and at night to fall back onto Eskom.  I would also like the system to be able to add batteries at  later stage and hopefully become somewhat independent of Eskom going forward.   

What could all you learned folks on here suggest or any advice you can provide would be appreciated.

Thanks for a great forum everyone.

 

 

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Firstly, that's a lot of electricity. You are using 3 times what my household uses on a busy day. So you can save/reduce load by getting a better idea of where your power is going and then controlling those items. Do you have an electric stove running a lot? Do you have lots of people doing this:

  • wake up
  • turn on the kettle
  • go back to bed
  • turn on the kettle
  • have a shower
  • turn on the kettle
  • get dressed
  • turn on the kettle
  • make coffee

To answer your actual question, you certainly can get what is called a "grid tie" system that will supplement the grid with solar when the sun is shining. Depending on the hardware you use you could add batteries later on.

I have a Goodwe inverter (OK... it's more than an inverter, but we'll call it that for now) and that can run without batteries and provide the grid tie function. If the load exceeds what the panels can provide then it will draw the difference from grid.

Again, identifying what uses power when can be a useful exercise. That way you can use timers to control your big loads so that they each get a turn with the solar power. My system maxes out at about 3.1 kw on a sunny day in September, but the total loads in the house can exceed that. If I can run those one after the other instead of all together then I have less need to draw from the grid. You won't get this perfectly right, but you can figure out how to make best use of the power.

You will probably have to split the circuits in your house into essential (and thus backed up) and non-essential. If there's a power outage during the day then the solar will supply the essential loads only. On my system the essential loads may not exceed 20A (30A for a short burst) at any time. So if there's load shedding then we lose some circuits, even on a sunny day.

Edited by Bobster
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You also need to look at exporting excess power - if the municipality allows that and if it makes sense to you to do so. That way you could be feeding spare power back into the grid when the demand from the house is low and that will reverse your meter for a while.

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Sorry... my standard advice: Get a COC after the installation and let your insurer have a copy. If the worst happens you don't want a loss adjuster saying "you really should have told us that you had the wiring changed." Also you may want to specify the panels and/or inverter. 

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29 minutes ago, Bobster said:

Firstly, that's a lot of electricity. You are using 3 times what my household uses in an average day. So you can save/reduce load by getting a better idea of where your power is going and then controlling those items. Do you have an electric stove running a lot? Do you have lots of people doing this:

  • wake up
  • turn on the kettle
  • go back to bed
  • turn on the kettle
  • have a shower
  • turn on the kettle
  • get dressed
  • turn on the kettle
  • make coffee

To answer your actual question, you certainly can get what is called a "grid tie" system that will supplement the grid with solar when the sun is shining. Depending on the hardware you use you could add batteries later on.

I have a Goodwe inverter (OK... it's more than an inverter, but we'll call it that for now) and that can run without batteries and provide the grid tie function. If the load exceeds what the panels can provide then it will draw the difference from grid.

Again, identifying what uses power when can be a useful exercise. That way you can use timers to control your big loads so that they each get a turn with the solar power. My system maxes out at about 3.1 kw on a sunny day in September, but the total loads in the house can exceed that. If I can run those one after the other instead of all together then I have less need to draw from the grid. You won't get this perfectly right, but you can figure out how to make best use of the power.

You will probably have to split the circuits in your house into essential (and thus backed up) and non-essential. If there's a power outage during the day then the solar will supply the essential loads only. On my system the essential loads may not exceed 20A (30A for a short burst) at any time. So if there's load shedding then we lose some circuits, even on a sunny day.

Hi.  

Thanks so much for you response.  

Yeh, I am at a loss here of what is using so much electricity.  Like I said, I had 2 geysers that were on permanently, and have recently invested in a Solar Geyser to provide the necessary savings of electricity, but I am still not satisfied that we are using this much electricity a day.  (Ave spend per month is between R 3500 - R 4000 per month. )

If I can make some kind of saving here that would help to fund the batteries i need to purchase.  

I think the first thing I will need to do is perhaps get my electrician out here and try to identify the power guzzlers (as per my knowledge, it is only the pool pump and geysers that utilise quite a bit.

Pool pump is 0.75KW x 6 hours = 4.5 KW or units -

Geyser 100L - 2KW element on for 2 hours a day = 4KW) 

Other Geyser Solar 150 L Top up in winter and early mornings (3KW element on for 2 hours a day) = 6KW

That takes us up to 14.5KW per day for these alone.  I am still missing another 26KW usage which I cant put my finger on.

Forgot to mention, that stoves are all Gas.  One electric oven (used maybe once a week) and other oven is Gas. So not attributing much to loss to this.

 

Any recommendations for how I can start tracking these usages?  

I have read about the Effergy units, but not sure how good or accurate they actually are.

Any advice would be appreciated.

 

Edited by mrafiq1303
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I can't help you with accurate identification of the loads. Though any hybrid system would give you a tool that will show what the totals are in your house at regular intervals. EG
image.thumb.png.9cc327e1d08d3ad90561a4f1659c358d.png
So there's a big increase in load at 6:30 which I know is the heat pump. Other spikes (today is a quiet day in our home) are kettle, microwave or the geyser warming up again. About 10:30/11 the load kicks up again because my batteries charged early, its a nice sunny day, and I figured some extra running of the pool pump isn't going to hurt anybody.

Tools like this don't identify the specific loads, but I soon learned to recognise most of them.

Does your stove run a lot? That'll use up power. A kettle or a microwave can use more than 2kw/h, though in shorter bursts.  Do you have aircon? Lots of heaters going in the winter? Electric blankets? 

Also check the thermostats on the geysers. Thinking about it, if you need to add cold water you've heated more than you need to. Also try cladding on the pipes and blankets on the geysers to reduce heat loss.

Geysers, stoves, kitchen appliances, pool pumps, anything else that makes heat. Are your dishwasher and/or washing machine heating water?

A lot of systems will give you a tool something like this. So you can play the game of installing first and figuring out what's going on later.

Edited by Bobster
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43 minutes ago, mrafiq1303 said:

Any recommendations for how I can start tracking these usages?  

I have read about the Effergy units, but not sure how good or accurate they actually are.

I would wonder about your general warm water use patterns. Bath vs shower, duration, frequency, etc. (6 x full, hot baths 6AM-7AM will take some heating where solar benefit could be diminished). 

Parents/you/teens mostly home during day (assuming non enforced Covid changes)? The bulk electricity use during the day will be oddish (barring the pool pump) if no one is home during the day.

Still coming out of winter... electric heaters on big part of the day?

Parents making tea often (boiling a full 2L kettle multiple a times to make 1 cup)?

Check pool pump flow rate spec and pool water volume and see if you actually need 6 - 8 hours (think general advise is to circulate/turn over the total volume of pool water about once in 24h) . When not using the pool during winter it can likely be even less - even more so if the pool is covered (also very good for reducing water loss...anyone remember that thing called drought?). My pool pump is about 1/2 my household electricty consumption.

Something like an effergy can be useful to identify times of increased electricity use. I prefer the basic effergy which is not web based.  Put the CT clamp on the mains breaker in the DB for a week, then use the software to check the graphs for spikes (you might then already be able to identify where electricity consumption spikes correlate with certain events).

If you have the time, then the/a  prepaid meter self can help identify consuming loads.  If daily routine is fairly predictable, then one "standard day" check you prepaid balance units, (switch off the pool pump breaker the night before), end of day check prepaid units, next day repeat exercise but allow pool to run - now you have a much more accurate indication (units and R/c) of what the pool pump consumes.

If you have a prepaid meter with little light that blinks at a higher frequency the greater the power use, then you can switch off circuits in the DB to see which circuit (geyser / / living room plugs / etc.) contributes greatest to the speed of blinking. Will give you an idea whether maybe the PC running in the study the whole day is using more electricity than you thought.

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4 minutes ago, introverter said:

I would wonder about your general warm water use patterns. Bath vs shower, duration, frequency, etc. (6 x full, hot baths 6AM-7AM will take some heating where solar benefit could be diminished). 

Parents/you/teens mostly home during day (assuming non enforced Covid changes)? The bulk electricity use during the day will be oddish (barring the pool pump) if no one is home during the day.

Still coming out of winter... electric heaters on big part of the day?

Parents making tea often (boiling a full 2L kettle multiple a times to make 1 cup)?

Check pool pump flow rate spec and pool water volume and see if you actually need 6 - 8 hours (think general advise is to circulate/turn over the total volume of pool water about once in 24h) . When not using the pool during winter it can likely be even less - even more so if the pool is covered (also very good for reducing water loss...anyone remember that thing called drought?). My pool pump is about 1/2 my household electricty consumption.

Something like an effergy can be useful to identify times of increased electricity use. I prefer the basic effergy which is not web based.  Put the CT clamp on the mains breaker in the DB for a week, then use the software to check the graphs for spikes (you might then already be able to identify where electricity consumption spikes correlate with certain events).

If you have the time, then the/a  prepaid meter self can help identify consuming loads.  If daily routine is fairly predictable, then one "standard day" check you prepaid balance units, (switch off the pool pump breaker the night before), end of day check prepaid units, next day repeat exercise but allow pool to run - now you have a much more accurate indication (units and R/c) of what the pool pump consumes.

If you have a prepaid meter with little light that blinks at a higher frequency the greater the power use, then you can switch off circuits in the DB to see which circuit (geyser / / living room plugs / etc.) contributes greatest to the speed of blinking. Will give you an idea whether maybe the PC running in the study the whole day is using more electricity than you thought.

Thanks for the response and suggestions.

Fortunately for me , no one baths.  All showers.  

I have noticed that my teen daughters have the electric blankets going at night, however.  They have been back at school since the beginning of August so no real day time usage until 3pm when they get home.

I will admit that the parents are real tea drinkers (even in summer) so have not really watched how they boil water etc.  

I like the idea of the blinking prepaid meter to see what circuits are they heavy pullers.  

I think I will invest in an Effergy to give me a clearer idea though.  

 

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It would be useful to see the actual usage of items. Some might actually draw more than their rating and other less. 
On first glance I would say the pool pump is going to be a big consumer. The geysers naturally also. Then Microwave, kettle and hair dryers are the rest of the usual suspects.

The fridge/freezers don't use that much, except if they are really old inefficient models. It is worth while looking at all the appliances. Plasma and projection type TVs use a lot of power (+600W). LED TV are low consumers (150-100W or sometimes less). Buying a new efficient model most times costs less than it would to get a bigger battery and inverter with panels to cover that load. 

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2 hours ago, Louisvdw said:

It would be useful to see the actual usage of items. Some might actually draw more than their rating and other less. 
On first glance I would say the pool pump is going to be a big consumer. The geysers naturally also. Then Microwave, kettle and hair dryers are the rest of the usual suspects.

The fridge/freezers don't use that much, except if they are really old inefficient models. It is worth while looking at all the appliances. Plasma and projection type TVs use a lot of power (+600W). LED TV are low consumers (150-100W or sometimes less). Buying a new efficient model most times costs less than it would to get a bigger battery and inverter with panels to cover that load. 

Thanks for the tips.  Really did not know Plasma's take up that much power.  I do have a Plasma that could do with replacing that is on most of the time.  

Think I will get me a Sonoff Pow R2 as well to test components draw.  (make up a lead) 

Anyone know where I can source and Efergy?  Doesnt seem to be in stock anywhere.

 

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7 minutes ago, mrafiq1303 said:

Plasma's take up that much power

Plasma works by heating up the plasma to make it glow. Anything that heats takes lots of power. (like geysers, kettles, stoves, hair dryers, etc. You get the idea :) )

If you are looking at going Victron in future I would suggest you buy an Carlo ET112 meter. ~R1000 and go into your DB. Those are very accurate and they measure the current and voltage and are part of the Victron ESS setup so is not useless in future. 

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3 hours ago, introverter said:

I would wonder about your general warm water use patterns. Bath vs shower, duration, frequency, etc. (6 x full, hot baths 6AM-7AM will take some heating where solar benefit could be diminished). 

This seems to me to be a good general point for any system that uses the energy of the sun. In my previous house we had a solar geyser. The way to get the most out of it was to use hot water in the afternoon thru to the early evening. Early in the morning when yours truly liked to shower the system hadn't had a chance to heat the water using the sun. I wasn't making the best use of the free energy. With solar systems you have to literally discipline yourself to make hay whilst the sun shines.

In the house we live in now I have had a heat pump installed. This works better for me - especially now I'm working for home. I run it on a timer and it draws a lot less power than a regular geyser and, I think, for less time. On a winter morning (since I had it regassed) it takes about 90 minutes to get up to 55 degrees, and uses about 1.2 kw whilst doing so. For the guest rooms we have a conventional element heated geyser and that draws about 3 kw.

Edited by Bobster
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What really helped me understand my electricity usage patterns is the energy meter I installed with my backup system. First few days I was running around like a mad-man, monitoring what appliances came on and their usage. Now I can basically just look at the time of day and the instantaneous usage and know exactly what is happening in my house, even when I’m not home.

Just with that, I was able to make my wife more energy conscious (I’ve always been very frugal, coming from a farming family where we saved water and electricity like mad) by showing her what it uses and costs (she is very clued up financially, so that wasn’t a difficult conversation).

Just using electricity better already helped a lot, such as:

- Switching off unneeded lights

- Not boiling more water than one needs 

- Not leaving heaters on or using them when extra clothes would do

- Not using the tumble dryer when the sun is out (washing machine is also a biggy if it needs to heat water, similarly dishwasher, but those are less easily optimised)

So then we got PV and shifted our loads. Granted, my current setup is west facing so early in the day it isn’t great, but that would be rectified in the medium term, but still we ended up saving 60+% on our purchases from the grid. I can likely improve upon  that, but not running my batteries below 60% at the moment. This is just due to my PV being somewhat underspecced, so on a good day, I’ll still struggle to meet my day time demands and bring the batteries up from 20% to 100%. We are in the process of adding more PV that would hopefully help with that.

Maybe my story helps you in your quest to save some of those kWhs!

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2 hours ago, Tariq said:

Hi MRafiq,

    I am not an installer, i commissioned my grid tied system in Cape Town about 6 weeks ago,  maybe I can help answer your questions

 

40 minutes ago, Bobster said:

Is it not the case that this is only an issue if you want to resell?

I am referring to the regulations on the website: https://www.capetown.gov.za/Family and home/Greener-living/Saving-electricity-at-home/going-solar.

https://resource.capetown.gov.za/documentcentre/Documents/Procedures%2c guidelines and regulations/Requiremenst for Samll-Scale Embedded Generation.pdf

Was just wondering if I will have to go through all this... or is this all outdated info?

 

 

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To legally install a pv system, you have to register it with CoCT, i have herd of the council using drones to locate unauthorized solar panel arrays and the fines are quite hefty . if you have a CoCT approved inverter and single phase it is not a major hassle anymore, was that your question ?

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Thanks.  

What kind of time frame are we looking at for COCT approval?  

If you look at the website, they require you to apply before you purchase and also for the installer to provide plans etc for the system which must be approved before you build.

So are you saying that if you have a COCT approved inverter and single phase, you dont have to do the application?

Thanks.  Sorry for all the questions, just want to know what I am letting myself in for.

 

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I can tell you what I'm doing now, since I'm literally in the process.

I spoke to @Jaco de Jongh, a highly recommended installer. I told him what I wanted, at a high level, he asked some questions then sent me a quote. I then had lots more questions, and we went back and forth on Whatsapp for about a week, tweaking stuff.

Now I have a final quote.

 

With that information (and some help from @Tariq :) ), I can mostly complete the CoCT form. The rest, I send to Jaco, and he fills in (technical details, diagrams, etc).

Then I'll submit that to CoCT. Tariq reckons his approval took about 10 days, so hopefully in that ballpark.

Then I'll get it installed, and apply for the commissioning with CoCT (again, hopefully about 10days).

Then I'm done.

 

Hope that helps, @Tariq can correct me if I'm wrong anywhere.

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