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Ready to start the solar journey - where to start?


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Hi guys

 

I grew up with an interest in electronics, playing with peg boards and electronics kits. I was heading towards a technical career, until the world of finance called. I still do the odd DIY project with DC and AC and get my hands dirty, but nothing hectic. Electrickery can kill you, so there's a healthy respect there. 

 

I, like many, am becoming increasingly frustrated with the loadshedding situation. I have managed fine by just being prepared and dealing with the inconvenience. However, I have a little one on the way (due late April) which changes things.  I cannot leave my wife and newborn at home with no electricity, especially due to the fact that I have no cell signal (I live in a cell signal dead spot). So it’s time to make a plan.

 

I have an efergy power monitor so I know what my average daily consumption and peak consumption is.  I have reduced my consumption pretty much as far as I can, by decreasing geyser temp, changing to LED lights etc.  I use about 4.5kwh per day (excluding geyser and stove) and apparently that’s pretty low.

 

Based on my interest in electronics and gadgets, together with the consumption and backup requirements, I have started looking around at various solutions. This forum was mentioned on another forum that I am on, so I came to check it out and am amazed at the amount of knowledge that is here. I have A LOT of reading to do!

 

Originally, I started off thinking small.  I need to keep the internet going for about 3 hours at a time. I checked my “box of random cables” and found that an old nokia 3310 charger fits the router and an old printer power supply fits the optical unit. I thought of cutting these cables and attaching to a decent 12v battery.  Charge the battery when AC available.  I could probably do this under R1k, as well as get some extra batteries and cheap Chinese DC lights/LED strips dotted around the house.  Bit of a hassle and manual intervention required. But ticks a box and is cheap.

 

OR….I looked at the long use UPS options. A basic inverter with 2 lead acid batteries in a trolley format, plug relevant appliances into trolley.  Lots of cheapies around and most have high voltage variances (only the 5kVa Axpert was ±5%, others were 10% or more). This option, with 200ah, was about R11k.  More capacity, can run more appliances, still a bit of hassle, requiring extension cords etc. But ticks more boxes.

 

OR….If I am going the inverter route, do it properly and wire into DB. Run all light and plug circuits. Don’t feel loadshedding. Happy days. Extra $$$. Then I think to myself, if I go this route I must add panels, and if I add panels, I might as well get a hybrid inverter and feed back into the grid (I have a rotational meter).  Here I was looking at a Goodwe 4ES 4.6kva with 2.4 - 4.8kwh and add some panels. And then I got a quote from an installer with a Schneider 4kw, Pylontech 4kwh system at R150k.  At this point, I get despondent and take a long walk to forget about it.  The slippery slope catches me and by the time I stop to look up, I have a system that way exceeds my budget and requirements.

 

I am going to read up more on this forum and hope that the slope isn’t so slippery this time round.  I am open to any and all advice, I really appreciate it.

 

Cheers

Craig

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  • Craigm changed the title to Ready to start the solar journey - where to start?

Hi Craig,

Welcome and congrats on the one on the way!

Yes 4.5kW /day is very low - you can bet that will go up once the little one arrives - but that's another discussion :)

It's exciting starting this - and with the help of forums like these you can avoid making mistakes up front - most of us have over time learned through experience.

Your thinking to go whole house I believe is the correct long term solution. Our electricity supply issues and price increases are  a guarantee for years to come, (we all hope not, but that's the reality) so becoming self-sufficient is definitely the right way I think.

So it all comes down to budget, what is available now, and what can be done later. Some parts you should do up front, and some things can be added/expanded later. Based on your electricity values I'm sure you should can get away for a lot less than 150k. 

With regards to "feed back" - also called "wheeling"- it's against regulation most places afaik, sure some people do it, but it requires a Hybrid inverter which costs more, or a grid tied which doesn't have battery backup and switches off during load shedding. To do it legally is another process altogether, requires professional engineering sign off, municipal registration, installation of a new meter for your cost etc etc.. all costing more than the amount of electricity you use in 2 years!

I'm not saying don't buy a hybrid inverter - in contrary there are a lot of good reasons to, but sometimes the cheaper options are perfect for meeting your requirements at a price you are comfortable with.

Your system is basically made up of three parts.

Inverters - There are decent affordable ones available that wont break the bank and supports lithium batteries properly.

Panels - Based on your usage will be the cheapest part of the solution - you'd be fine with 6 panels (generates around 15kWh per day)

Batteries - Forget about LA (Lead Acid) - Lithium is your friend. There are two options here - New branded ones (Think Pylontech, Dyness,), or cheaper alternatives/even some locally made DIY ones mentioned on the forum which offer very good value. It's a longer discussion, again based on your budget might be the best option for you for the next 3-5 years.

I'd install 2x inverters up front, probably 6 panels to cover your load and have excess to keep the batteries charged, and look at a 2nd life type Lithium or DIY lithium option - between 6-9kWh.

Something like this should be possible for around 120K with a branded "2nd life" battery. It would generate roughly 15 units per day, and give you roughly 5 hours of backup time when running @ 1.5kWh load.

If you are extremely efficient and don't have any peaks over 5kW ever (maybe no geyser, or a small element, no electric stove etc) - you could try 1 inverter, which gets you close to around 105K. Staying with 2x inverters but going smaller capacity DIY battery will also be around 105K. - Less backup time (3 hours @ 1.5kW)

If you opt for a DIY battery option  (stock might be an issue for a while - they sell out very quickly) + single inverter you could probably get down to around 90K - with less backup time - say 3 hours @ 1.5kW. 

If you want more info - welcome to ask/PM - if you are in the Cape - I can suggest some good guys.

 

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1 hour ago, Igubu said:

Yes 4.5kW /day is very low - you can bet that will go up once the little one arrives - but that's another discussion :)

If the little one arrives in winter, and you have to keep a room warm... that's the biggest consumer. Of course many people also buy a tumble dryer at this point. If you're looking at doing such a thing, definitely look at the more energy efficient options. I found that the Bosch condenser dryer is definitely more efficient than a normal Defy vented one, and I also discovered recently that the heat-pump units are no longer an arm and a leg... they are only an arm or half-a-leg now 😛

11 hours ago, Craigm said:

attaching to a decent 12v battery

Of course you have to make sure the router actually has a 12V PSU, but I'm sure you did. You can buy small SMPS boards from hobbyist places for next to nothing, as little as R25. Just always remember to fuse it.

11 hours ago, Craigm said:

long use UPS options

What I would actually suggest is a bit of a middle-of-the-road approach. Go with the UPS trolley, but use a better inverter, one that can actually serve the whole house at some future point. @Jaco de Jongh built one for @Ironman, like this, but at this moment most solar installers are totally overworked, some even turn their phones off for a part of the day just to get the quotes done. Also, lead time on batteries is in the 1-2 months bracket.

What I did in my house (with the help of a friend 🙂 ), is I fitted two of these 32A generator/welding plugs to the wall. The entire solar system lives in an old network cabinet, and simply plugs in. It has the additional upside that if I need to use a backup generator, it will plug in really easily.

Of course this is going to be quite a bit more than the 11k hardware store one, but it will be way less than the 150k full home one.

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Also, can I just add... you will learn soon that the ability to heat two tablespoons of mashed pumpkin in a microwave oven for exactly 11 seconds while the baby is crying his head off and all the world is dark around you... is worth all the money you spent on it 🙂

Also, as a long-time father, I will advise you to change as many diapers as possible before the baby goes onto solids. Get some credit down...

Edited by plonkster
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11 hours ago, Craigm said:

I am open to any and all advice

My advice is not to invest into a PV system of any kind at the moment (except if it is your hobby or you passionately feel about your CO2 emissions). The ROI (even for a GTI without batteries) is at the moment simply to long. To combat load shedding is however a different story. We will have years (maybe decades) of load shedding ahead. So to invest into a small back up system I think is essential. I would install a small Axpert type inverter with about 2kWh of lithium batteries. There is also a good chance that some kind of government or municipality residential PV subsidy program will be launched soon. If that happens and ROI becomes attractive you can sell your UPS inverter and upgrade to a proper grid tied Inverter and solar panels.   

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5 minutes ago, Fuenkli said:

My advice is not to invest into a PV system of any kind at the moment (except if it is your hobby or you passionately feel about your CO2 emissions). The ROI (even for a GTI without batteries) is at the moment simply to long. To combat load shedding is however a different story. We will have years (maybe decades) of load shedding ahead. So to invest into a small back up system I think is essential. I would install a small Axpert type inverter with about 2kWh of lithium batteries. There is also a good chance that some kind of government or municipality residential PV subsidy program will be launched soon. If that happens and ROI becomes attractive you can sell your UPS inverter and upgrade to a proper grid tied Inverter and solar panels.   

As @plonkster said - when a little one cries, hot milk is required in 11 seconds, you need to wash 3 loads of baby grows a day  - "roi" doesn't feature high on the list :)  Happy wife and sanity does though.

But on a more serious note - would be interesting to understand your opinion about ROI being to long? If you are a small energy user, then sure, as most proper systems really cover a minimum load much higher than a very efficient user needs - so yes, 6, 7 years, but if you are in the R2000+ pm electricity bracket, (2 geysers, family of 4, pool pump, perhaps borehole) then the ROI is in fact much shorter. If you are on a farm, and have to pay availability/network fees (R5000 pm + for a small 3-phase feed) where your actual electricity usage is low (R2000pm - Total bill R7000) then the ROI is very short under 4 years at current prices, probably break even in less than 3. So it really depends.

A colleague of mine went down the road of that trolley recently - a big sports fan, so just HAD to keep the TV going and internet for the family. So bought a trolley inverter (mecer), and two big batteries - started up nice, all the light on great. Great excitement :) The moment they added a bit of load, the fans start spinning and the noise increased to an unacceptable level for the whole family.  So it "works" but not suitable to use in your living room. End result spend R15K on a "workaround" that is now packed away...

I'm not holding my breath for any subsidy soon  - the same way I doubt allowing COCT to buy from IPP's will change the current feedback scheme in any way  - ie it will still not be beneficial to register and feed back for most residential users - the only difference is perhaps more stability, and who knows, maybe a cheaper rate at different times.

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12 minutes ago, Igubu said:

not suitable to use in your living room

So use an extension cord... geeez 🙂

With my latest install I did worry a bit about the location of the inverter. It is in the laundry room, just adjacent to the kitchen. I can actually hear the inverter fans from where I am sitting now. But because it is in a network cabinet and the door is closed, it's not all that loud.

Same thing really with generators. You're not going to put that thing right below your living room window, you're going to put it some distance off. Like... right below your neighbour's bedroom window, so he can listen to this sound track ... see below for an actual recording of my neighbour's generator.

I think what gets me most about the sound of a cheap petrol generator... is that slight irregular miss it throws in every now and then. I can see that me and my new neighbour might have some issues. Neighbour has had a break in... or more like a walk-in-and-take-the-handbag. Neighbour says perp came over my wall. My security footage shows nothing. My wall is higher than hers. Neighbour wants to install razor wire on my wall. Me not happy. Neighbour's place looks like a permanent yard sale. The offending generator is in the middle of the lawn, no shade... the former red colour of the fuel tank long bleached into a vile pink.

generator.mp3

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@Igubu thanks very much for your repose!

2 hours ago, Igubu said:

With regards to "feed back" - also called "wheeling"- it's against regulation most places afaik, sure some people do it, but it requires a Hybrid inverter which costs more, or a grid tied which doesn't have battery backup and switches off during load shedding. To do it legally is another process altogether, requires professional engineering sign off, municipal registration, installation of a new meter for your cost etc etc.. all costing more than the amount of electricity you use in 2 years!

Thanks for this.  I think I will take this off the table for now.  It is not a primary objective. However, if I do end up going for the hybrid option, I can consider this at a later stage.

Grid tied (no batteries) doesn't line up with my objectives of my current system requirements, so this is also off the table for me. I need the batteries for "outages".

 

2 hours ago, Igubu said:

I'm not saying don't buy a hybrid inverter - in contrary there are a lot of good reasons to, but sometimes the cheaper options are perfect for meeting your requirements at a price you are comfortable with.

2 hours ago, Igubu said:

If you are extremely efficient and don't have any peaks over 5kW ever

Could you suggest some inverter options that I could look at?

I looked at my efergy monitor data and noted that my average peak is 2.8kw. Average idling consumption is <350w.  I can manage consumption to ensure that peak does not exceed 3kw. However, I am also happy to go a little bigger (I do not want to buy a small inverter and cry in a years time when its too small).

2 hours ago, Igubu said:

Your system is basically made up of three parts.

Thanks for this explanation. I think, based on the info I have thus far, that I need batteries and the panels can come later. But I'll be itching to get these on as this is where the cost saving potential is.

 

2 hours ago, Igubu said:

If you want more info - welcome to ask/PM - if you are in the Cape - I can suggest some good guys.

Thanks very much for the offer.  I am based in Pretoria.

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1 hour ago, plonkster said:

If the little one arrives in winter, and you have to keep a room warm... that's the biggest consumer. Of course many people also buy a tumble dryer at this point.

She is coming in April, so will still be small in winter. I have a portable gas heater which we use instead of the aircon. But we will have to see how this goes.

Tumble drier, together with other electricity guzzlers, are swear words in my house.   I have managed to get my consumption very low due to the lack of these sort of appliances (no tumble driers, pool or borehole pump etc).  I even managed to convince SWAMBO that hairdryers aren't that great :)

 

1 hour ago, plonkster said:

Of course you have to make sure the router actually has a 12V PSU, but I'm sure you did. You can buy small SMPS boards from hobbyist places for next to nothing, as little as R25. Just always remember to fuse it.

I have checked, both the optical unit and the router are 12v (1A and 1.5A).  I havent started looking at charging units yet though, so I will check back in with you if I do go this route.

 

1 hour ago, plonkster said:

What I would actually suggest is a bit of a middle-of-the-road approach. Go with the UPS trolley, but use a better inverter, one that can actually serve the whole house at some future point. @Jaco de Jongh built one for @Ironman, like this, but at this moment most solar installers are totally overworked, some even turn their phones off for a part of the day just to get the quotes done. Also, lead time on batteries is in the 1-2 months bracket.

Based on my requirements, I think if I go for this size unit, I might as well wire it into the DB.

I agree on the overworked part. The company that I work for has some involvement in solar in some of our subsidiaries, (they focus on distribution and large commercial designs and installations) who just haven't had the time to help me look at my tiny  residential system requirements.  And I guess it is only going to get worse (better?).  Based on this, once I have a solid design, I will try to source the parts through these guys, depending on brands obviously.

1 hour ago, plonkster said:

Also, can I just add... you will learn soon that the ability to heat two tablespoons of mashed pumpkin in a microwave oven for exactly 11 seconds while the baby is crying his head off and all the world is dark around you... is worth all the money you spent on it 🙂

Thanks for this.  Maybe I should start another thread on first time parenting advice? :)

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1 hour ago, Igubu said:

If you are on a farm, and have to pay availability/network fees (R5000 pm + for a small 3-phase feed) where your actual electricity usage is low (R2000pm - Total bill R7000) then the ROI is very short under 4 years at current prices, probably break even in less than 3

I agree. In this situation it makes financial sense to go "off grid" with a PV system and a back up generator. 

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1 hour ago, Fuenkli said:

My advice is not to invest into a PV system of any kind at the moment (except if it is your hobby or you passionately feel about your CO2 emissions). The ROI (even for a GTI without batteries) is at the moment simply to long. To combat load shedding is however a different story. We will have years (maybe decades) of load shedding ahead. So to invest into a small back up system I think is essential. I would install a small Axpert type inverter with about 2kWh of lithium batteries. There is also a good chance that some kind of government or municipality residential PV subsidy program will be launched soon. If that happens and ROI becomes attractive you can sell your UPS inverter and upgrade to a proper grid tied Inverter and solar panels.   

Thanks @Fuenkli. I didn't expect that answer at all, but it's refreshing to see the honesty!  Based on my consumption, I know my break even point is far far into my future.  I did the sums on a solar geyser (based on consumption at the time) and it was a 30 year break even period. I wont be in the house that long. Decided not to go that route until something drastically changes.

The trolley option I view as a pure cost and will be for convenience only.

I hear you regarding the subsidy. But I am also cognizant of the fact that panels might be taxed at some point, which we cannot factor into our calcs at the moment.

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25 minutes ago, Craigm said:

She is coming in April, so will still be small in winter.

The critical part is the first two weeks, also sometimes known as the "honeymoon" period. That's the part where they still sleep a lot, and where it is best to keep them warm. You'll be long over that by winter 🙂

During the honeymoon period, they awake frequently, but they sleep a lot. This leads some parents to prematurely declare that it is not as bad as everyone told them... and then everything changes! Mommy gets blue rings under the eyes, you move to the guest room with your daughter to give the wife a rest, there are various wipe things around that smell like sour milk... etc etc... but in the end, it does pass 🙂

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On 2020/02/21 at 11:13 AM, Craigm said:

@Igubu thanks very much for your repose!

Thanks for this.  I think I will take this off the table for now.  It is not a primary objective. However, if I do end up going for the hybrid option, I can consider this at a later stage.

Grid tied (no batteries) doesn't line up with my objectives of my current system requirements, so this is also off the table for me. I need the batteries for "outages".

 

Could you suggest some inverter options that I could look at?

I looked at my efergy monitor data and noted that my average peak is 2.8kw. Average idling consumption is <350w.  I can manage consumption to ensure that peak does not exceed 3kw. However, I am also happy to go a little bigger (I do not want to buy a small inverter and cry in a years time when its too small).

Thanks for this explanation. I think, based on the info I have thus far, that I need batteries and the panels can come later. But I'll be itching to get these on as this is where the cost saving potential is.

 

Thanks very much for the offer.  I am based in Pretoria.

Hi Craig, A brand that seems to be good value is called Growatt. (essentially a re-engineered "Axpert"  - made by a different company  - better internals, longer warranties, lithium BMS/CAN Bus support etc) - Model spf-5000tl-hvm-p.  International site www.ginverter.com - just be aware the online .pdf manual (last time I checked) was still V 1.0 - There is an updated manual available if you want to read through. It's a 5kW unit, can spike to 10kW for short periods - so you could probably get away with a single unit at this point. It's an off-grid inverter, so no "blending" of power sources - it's either PV, PV+Battery or Eskom (you can configure all the switch/switch back levels for this - for low load like yours with a right size battery bank your would probably switch in rare cases only  - like middle of the night, batteries empty because of say loadshedding between 16:00-19:00)

With regards to Panels "later"- rough idea is 6x 365W panels would be around R14k - (less than the 2nd inverter costs) - and would probably cover your 90%, maybe even 100% - so makes your payback quicker for sure. Often installers would charge you a day rate for installing inverters, electrical and panels (your type install will definitely be done in a day) - and getting them back another day to just mount panels will incur labour charge again - but of course look at your budget.

Regards

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