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Hi I need a lot of advice. I am thinking of goiing solar. My daily usage is about 30 kw/h. I am thinking of first installing a 4 - 8 kw inverter wit a small bank of batteries just for load shedding purposes. This part of the installation can be done by an licenced electritian. I then plan to add panels to the installation myself as finances permit, until i reach the optimum number of panels. Let s start with the questions.

1. I am looking at the 4 kw axpert or the Sinerji the are of similar specs and price any ideas from the old hands

2. The part of installing the panels can it be done by a lay person?. I am quite nifty with my hands but don' t have much expierience with electicals, safe wiring the odd plug or installing my own alarm and ctv cameras. Is it legal for lay person to do the 48v part of the installation

rest of my questions i will post as the project develops

regards

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Welcome Thinus. 

You've come to the right place.

Where are you based, for that has a impact on some of the advises.

Yes, you can install the panels yourself. The electrician you are thinking of must understands the differences between solar and Eskom. I have lost equipment because a electrician did not understand the implications. There are installers here on the forum who can help also. 

And all the ideas and advice here is free. 

Right, first question: You understand the difference between NEEDS versus WANTS? NEEDS cost a boatload less than WANTS ito solar systems.

You also must understand that solar is either a hobby, or it is a need. Eskom, once you have reduced your load, which costs a lot by itself, is cheaper than batteries. Even more so if you have to borrow money to install a solar system. Hobbies have no price tag.

Right, last question for now, just to make sure, 30kw/h is 30 000 watts per hour, or 30kw used per day?

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11 hours ago, Thinus Jacobs said:

Is it legal for lay person to do the 48v part of the installation

I don't think there is presently any legal requirements for that side of things. There are legal requirements that kick in the moment it becomes grid connected. Mostly, you are allowed to do the work yourself (other than the AC side, for that you need a licensed electrician), but it has to be signed off before you can grid-connect it. To what extent it must be signed off depends on where you live. What I'm getting at is there are no rules that specifies WHO must do the work, but there are rules that says HOW it must be done to be safe, and WHO gets to decide if it was done right.

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Thanks Terrible triplet as well as Plonkster  for your replies. 

Yes is understand the need / want thing That is why I only want a small battery bank for the times of load shedding. IMwill use eskom as my backup mostly when they are available. I understand batteries are expensive and have short livespans. Your first question. i live in Bloemfontein. 

I am thumb sucking the 30 kw. It is the average usage per day in units on my prepaid electricity meter. I will have a load test done before i embark on anything. 

What is your thoughts on the Axpert vs Sinerji inverters? Victron is just to expensive for me

 

Plonkster my plan was to have the inverter installed by electrician as welle as coupling to the grid. The installation of batteries and panels I am prepared to do myself.  Guys in Bloem are rediculous with installation costs. Something like materials x2 

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28 minutes ago, Thinus Jacobs said:

I am thumb sucking the 30 kw.

You must start here. Get the exact figure. Then you reduce is as best you can.

Otherwise it is like putting the cart before the horse. Been there done that too.

Every single mistake that can be made, has been made my one of us on this forum.

We now have the formula.

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2 minutes ago, The Terrible Triplett said:

We now have the formula.

Let me explain more.

IF you get the load wrong, you could end up with the wrong inverter.

You cannot have a small bank unless the inverter can limit the charge to the batteries, set the max charge, otherwise the full amps will plough through the batteries shortening their life immensely. So that is a point to ponder OR go grid tied, but lets not go there yet.

If you have the correct information ito your loads i.e. the max watts possible drawn, the average watts over 24/7/365, the lowest you can get it all, then the advice's given and equipment suggested, will be as accurate as it can be.

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16 hours ago, Thinus Jacobs said:

The installation of batteries and panels I am prepared to do myself

Depending on where you put the panels, your insurance company might not like it if you didn't get a structural engineer to approve the plans. If you put them on your own structure or on a carport roof like mine, then at least there is a lower risk. I think the important thing is to earth them properly.

16 hours ago, Thinus Jacobs said:

thumb sucking the 30 kw. It is the average usage per day in units on my prepaid electricity meter

Mine was 40kwh. I lowered that to around 25 just by changing lights, appliances, and so on.

Quick note again on kw vs kwh... because I see you making that same mistake :-) One is a measure of power, the other is a measure of energy. Power has a time component, if I do the same work in half the time, I have double the power. If I pump the same amount of water in half the time, I will use the same amount of units on the meter, but use double the power while I'm doing it. A Watt is a Joule per second, so a if you draw a kilowatt for a whole hour it's 3600000 joules, or 1 kwh. The h cancels out with the "per second", making kwh (counter-intuitively) a unit that's actually timeless.

16 hours ago, Thinus Jacobs said:

Something like materials x2

So on the last 3-panel job I did, I spent 7k on the panels and 2k on the aluminium for the frame, let's call it 10k. Would I pay someone to 20k for the whole job if I could not do it myself... mmmmh... I just might if I wanted it done properly :-)

So I put this job in that category of things that I know well enough to pay myself 10k to do it. But individual mileages may vary :-)

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As everyone has said here, understanding your usage first is paramount. It will be well worth your while to get a power monitor first so you can see what and when your power usage is. 

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Hi

I had the same requirements and did the following 2 years ago.

  1. Installed a Solar geyser with Eskom as back up if more warm water is needed. (R13k)
  2. Installed a solar system consisting out of 3 x 300W Renesola Panels, 1 x 5KVa Axpert inverter and then 4 x 200A Vision batteries. Replaced all lights in the house with LED or power saver bulbs. (R40K). Except for the solar panel installation I did all the rest myself (Panels on a 2nd story roof with not a lot of movement space). All the lights and power to three rooms is handled by the system. The rest of my house is still on normal Eskom.

Results:

  1. I brought down my consumption from 25 to 15kWh per day. I have a saving of R500/ month on my electricity bill. Biggest saving is done on the geyser. Over the last two years, my geyser has only been on for 25% of the time when warm water was required, rest of the time the sun did all the work. (Require warm water for 3 hours per day)

Hope that the information is helpful. As @The Terrible Triplett said you are on the right place for advice, guys here always willing to help.

Regards

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Hi ridiq thanks for your info. I already dit the solar geyser thing as well as the LED lights. I think my main culptits power wise as a 30 yr old double door fridga as well as old chest freezer which I aim to replace soon. I think my power usage will be down to 15kwh per day then. 

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@Thinus Jacobs also keep in mind that you dont need or should provide for the topside of your consumption. In other words if your that max amount of load that your house uses at one time is 5kw you should not get a 5kw system. As you noted - old equipment like a fridge is a big power hog as it runs 24/7. Even lights does not make that a big difference unless it is on for 12h a day. If you have 5x20w spotlight running for 12 hours as "security"  that is 1.2 kwh gone a day. Try and get your base load (Thats the stuff that runs for 24/7)  as low as possible after that you will have a general idea as to what you should get and then if it is worth the capital that you will spend. 
But again that is only true if you look at this from a cost savings perspective 

P

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8 hours ago, Thinus Jacobs said:

30 yr old double door fridge

Even 10-year old ones can be a hog. The cheap ones have 250W compressors and run as much as 12 hours a day (ie they are on half the time). So 12 * 0.25 = 3kwh. Which might not sound like a lot, but usually you have a fridge and a freezer so it adds up to around 6kwh. That's the situation I dealt with. Replaced both with low-energy units, got it down fro 6kwh to 2kwh.

Replacing your fridge with something decent (like the nice Bosch A++ units) is a must. Wanting to save power is such a good excuse to get a decent fridge with lots of space that actually keeps the food cold, has nice glass shelves, etc etc. Happy wife happy life!

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@Ridiq here is what we did over time:

Then we started:
1) Started wit lights, found that saving negligible once one has change the bulbs, installed timers and motion sensors with some serious family guidance on the matter. Do have a changeover switch though, in the event that Eskom woes do return, to switch lights back to solar.
2) Geyser, as you found, was the biggest user of electricity. Today, after family guidance and alleged water restrictions, we don't use Eskom at all for the geyser. :-)
3) The main reason for my system is the +-800w office computers and other things we use during the day. Batteries too expensive to replace Eskom at night.
4) Next the fridge and freezer was replaced, as they where the 3rd biggest users. Today they are on solar 24/7/365 being A++ and all that, as they can run on my small inverter due to low startup currents.
5) Small 24/7 loads like Wifi, alarm system, door interkom etc are also solar.

Never bothered with kitchen for the loads there are on for minutes like microwave, kettle, needing a huge inverter if both are on. Oven/stove uses more but again, cost of a huge inverter and load management if all is on, just too much effort for what saving?

The 24/7 loads are the ones costing money. Not the peak loads.

Loads on solar changes between winter/summer, to not go below 80% SOC, yet have enough time to recharge the next day and power the daytime loads.

Running my small system to its max see. :-) 

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41 minutes ago, The Terrible Triplett said:

The 24/7 loads are the one costing money. Not the peak loads.

This is the point people miss so often. When people think large power users, they think geyser (correct), stove (wrong!), hair dryer (wrong!), kettle (wrong!), etc. Energy is measured in kwh (kilowatt-hour), that is literally multiply them. If the h factor is very small, it might not matter that the kw factor is large. In reality, loads with a large h is much more costly in the long run.

The trouble with the geyser, of course, is that both factors are potentially large, but that depends entirely on your hot water use. It takes 1.16wh to heat one liter of water by 1 degree centigrage. Plus 2kwh standing loss on top. That's how much a geyser uses. As TTT points out, with the water restrictions this side... even those without solar geysers use only around 2kwh (the standing loss part) for hot water.

(That means that in many houses the fridge uses more energy than the geyser!)

In fact, when I draw a bath for the kids, I put in around 10 liters of cold water in the tub, then chuck in two kettles of boiled water. Nice hot bath, and I didn't have to waste any water while waiting for the hot water to arrive down that 20 meter pipe from the geyser... :-) The only reason I leave the geyser on is to avoid legionnaires disease.

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5 minutes ago, plonkster said:

... arrive down that 20 meter pipe from the geyser.

That reminds me. Also something we did, we split the house between the main geyser that feeds the bathrooms, and the kitchen and one other bathroom on the other side of the house.

The water wasted, and the geyser cooling down per day just for a few liters of warm water, made a 2nd hand 50l geyser for the kitchen and that 1 bathroom, much more viable.

8 minutes ago, plonkster said:

... when I draw a bath for the kids,  I put in around 10 liters of cold water in the tub, then chuck in two kettles of boiled water.

Clever!

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14 minutes ago, The Terrible Triplett said:

Clever!

Sometimes the kids want to play in the bath, and you get to dump them both in simultaneously. Sometimes the female one is difficult (I think she must get it from her mother)... then the kettle trick is also useful. After boetie is done, quickly chuck in a kettle of water to get the heat back up... sorted for sussie.

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What  I also discovered is how energy inefficient computer hardware can be. I got rid of the pc (450W easy)and we only use laptops (80W max for both) nowadays. The laptop only uses mains power when its charging as well, and usually takes less than a hour to be charged and ready for the next 6 or 7 hours. I use my cellphone as a wifi router as well...

 

  

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On 2018/02/27 at 10:50 PM, Thinus Jacobs said:

/-/*-/-Hi I need a lot of advice. I am thinking of goiing solar. My daily usage is about 30 kw/h. I am thinking of first installing a 4 - 8 kw inverter wit a small bank of batteries just for load shedding purposes. This part of the installation can be done by an licenced electritian. I then plan to add panels to the installation myself as finances permit, until i reach the optimum number of panels. Let s start with the questions.

1. I am looking at the 4 kw axpert or the Sinerji the are of similar specs and price any ideas from the old hands

2. The part of installing the panels can it be done by a lay person?. I am quite nifty with my hands but don' t have much expierience with electicals, safe wiring the odd plug or installing my own alarm and ctv cameras. Is it legal for lay person to do the 48v part of the installation

r*e*st of my questions i will post as the project develops

regards

1. What is the max load your house needs? How many Kw power does the house draw when everything you need on, is on?  You would be surprised to know that you often need more Kw energy than you thought you might need. When there was a power failure, how long does it take the fridge to cool down enough for the pump to run a bit slower? And how much energy does the heatpump / pool pump / geyser use on startup? 4Kw isn't a lot of power - When you make coffee, while the dishwasher is on, those two items alone could consume 5Kw!

2. Yes, anyone capable to lifting panels onto the roof and using spanners could mount the panels. Experiences installers would have more knowledge and experience in many instances though. Like which mounting structure to use, how to cater for wind load / rain / snow (where applicable), etc. But there is no legal requirement, right now for this part to be done by a certified individual (no classification for this either yet). But the inverter connection to the house needs to be done by a certified electrician if you want / need a COC - for insurance purposes, or if you sell the house. Many people don't worry about this and get a electrician from Builders for R250/day. 

Both scenarios above isn't ideal, but can be done on a tight budget. You could always get a master installer to sign off the COC later (could cost anything between R1000 and R3000) 

 

In most cases you can start off small and upgrade as the finances are available, i.e. get the Axpert inverter with 3x 250W panels and a small 48V battery bank. If the batteries won't ever be used (i.e. you have very little to no power failures, and the batteries are purely used to power the inverter), a small bank would work for now. A 2.4Kwh Pylontech battery would power the inverter, don't cost much (about R15k) and will last about 10 years. 

On the other hand if you need the batteries to last long and perform well, you would need to spend some cash on a properly sized battery bank. i.e. "deep cycle" batteries are not for solar use. This is the one item, where the more you spend, the better it will work and the longer it will last. 

Solar panels are cheap these days, but it's still worth-it to buy some of the better brands. Look at the different panels efficiency rating (on the panels spec sheets) and see what you can fit into your budget. JA Solar, Canadian Solar, etc are good panels and not too costly. 

And, lastly, don't skimp on protection! Use properly rated DC fuses, i.e. 1000V PV for your solar panels, a DC Fuse disconnect is a bit costly, but will save your investment and life. Use AC surge arrestors before, and after the inverter, and a PV Surge arrester on the PV side as well. 

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