Starting my grid-tied solution to load shedding

[Rclegg]

Hey all, 

As with everyone in this country; I am done with Eskom's BS. 

I'd like to design a system for my house to initially start out providing the house with power during load shedding periods. I'd like to then upscale the system to the point where Eskom is just a backup. I believe this is the Hybrid system (Grid-tied)?

The requirements I have for such a system is this: 

1. I All plugs in the house should be on inverter power 

2. All lights should be on inverter power (80% are LED - will be changing the remaining to LED) 

3. Should be able to run the ceiling fan / light 

Current power consumption is on average 30Kw a day (Have one ion those smart meters that gives readings; not sure on accuracy ?) 

We won't need to run the follow for the moment: Pool pump, geyser, stove A/C. Eventually the system should be able to run all that except the stove as we will move that to gas. 

I'v done some research and unfortunately I just have more questions than answers; hoping this helpful forum will be able to assist. 

1. Will a 5Kva inverter be enough? What brands should I be looking at (And staying away from) 

2. Batteries - Would it be better to go with 105ah batteries for now or use 200ah batteries - need to keep the house running for 4.5h min 

3. Do I need to have a manual change over switch by the DB? (I know the inverter will do it; but not sure on the law / regulations) 

4. Do I need a second DB according to regulations / law? (I am probably going to install one regardless, but would like to know) 

5. Do I need to have a certified installer; or can I get someone knowledgable to install and then get someone to certify the system for me? 

6. Do I need to register NERSA / COJ for the system to be 'legal' 

 

Finally, let's say I want to upscale to solar - besides the PV panels / roof mounting kit - what else would I need to add to the system?

Budget wise; what should I be looking at to spend here for the short term (Just getting relief from load shedding) I am thinking in the 25 - 30k mark? excluding anything related to solar

 

Appreciate any feedback; I am completely new to all this and might not understand it all 100%. 

[phil.g00]

1 hour ago, Rclegg said:

Current power consumption is on average 30Kw a day

I take that is 30kWh a day, learn the correct units or you'll get bum steers like many have before you.

You shouldn't size for average, you should size for peak.

It isn't enough to know what you use in a day, you'll need to know what your peak usage is in kVA and the peak in kWh (or kVAh) usage over any given 4.5 hour period.

In other words, your loads wont be constant throughout the day, and your maximum demand matters.

So start by recording your  normal usage for a month or so, in a way that you can answer these questions.

Then change your usage patterns, both by reducing usage and by scheduling the loads differently, and record for another month.

Then look at what you need.

 

Edited January 13, 2020 by phil.g00

[Rclegg]

35 minutes ago, phil.g00 said:

I take that is 30kWh a day, learn the correct units or you'll get bum steers like many have before you.

You shouldn't size for average, you should size for peak.

It isn't enough to know what you use in a day, you'll need to know what your peak usage is in kVA and the peak in kWh (or kVAh) usage over any given 4.5 hour period.

In other words, your loads wont be constant throughout the day, and your maximum demand matters.

So start by recording your  normal usage for a month or so, in a way that you can answer these questions.

Then change your usage patterns, both by reducing usage and by scheduling the loads differently, and record for another month.

Then look at what you need.

Yes, sorry, I meant kWh. 

Is it enough to use the smart meter for this recording?

It has day-today recording and current usage as well. I checked when I got home and 30 is more than any single day since moving in

So, for example, the last 6 days usage is as follows: (According to the meter) 

• Tue: 21 kWh 
• Wed: 22 kWh 
• Thu: 17 kWh 
• Fri: 10 kWh 
• Sat: 18 kWh 
• Sun: 23 kWh 
• Today (so far): 12 kWh

Weeks:

• W01: 114
• W02: 12 (I think it stat a week on a Monday) 

30 kWh would be very high usage for us on a given day actually - not overage usage. My mistake. 

Thanks for the feedback. 

Edited January 13, 2020 by Rclegg

[phil.g00]

No, a daily meter is not good enough for the reasons I have already outlined.

If the future of your system is to be a legal grid connection you may be restricted in inverter size by rules.

I think given your budget you should consider a professionally installed standby generator.

But again sizing it properly is still required.

Edited January 13, 2020 by phil.g00

[Rclegg]

5 minutes ago, phil.g00 said:

No, a daily meter is not good enough for the reasons I have already outlined.

If the future of your system is to be legal grid connection you may be restricted in inverter size by rules.

I think given your budget you should consider a professionally installed standby generator.

But again sizing it properly is still required.

Right, I hear you. 

What would be an effective way to measure the loads in  kVA and the peak in kWh (or kVAh) 

My budget isn't 30k. I stated that as starting point. I want to avoid having to run a generator and want to continue down the renewable energy path. I haven't worked out my budget; but that is something I can work on to increase for a system that will suit my needs. 

Thanks again

[___]

3 hours ago, Rclegg said:

1. Will a 5Kva inverter be enough? What brands should I be looking at (And staying away from) 

It depends on the peak you need to be supported. I my house we get by on a 3KVA quite easily. Don't ask about brands because we you might as well ask Hilux or Ranger... Everyone knows the Hilux is king, but man... the money!

3 hours ago, Rclegg said:

2. Batteries - Would it be better to go with 105ah batteries for now or use 200ah batteries - need to keep the house running for 4.5h min 

I will always recommend the 200Ah over the 105 jobbies. Those 105-batteries are meant for UPSes and they are not going to last. I can't say if it is enough to run for 4.5 hours... it depends on your load during that time. Multiply your average load by 4.5 (hours), then multiply that by 2 (so the batteries are only discharged to 50%)... and divide by 50 (just to make the math easy, the battery voltage). So as an example, a 500W load, times 4.5 is 2250, times two is 4500, divided by 50 is a 90Ah battery.

3 hours ago, Rclegg said:

3. Do I need to have a manual change over switch by the DB? (I know the inverter will do it; but not sure on the law / regulations) 

Regardless of whether it is a requirement, put one in anyway. There are times you need to bypass the inverter so you can do work on that side of the system, and the long-haired bipeds don't like it when the power is down.

3 hours ago, Rclegg said:

4. Do I need a second DB according to regulations / law? (I am probably going to install one regardless, but would like to know) 

Regulations require clear separation of backup circuits and non-backup circuits. It is allowed to be in the same board, but the distinction must be clear, and your backup side must have its own RCD, split neutrals, and so forth. Most people run out of space once they have to add the changeover and additional RCD, so they end up with a sub-DB anyway.

3 hours ago, Rclegg said:

5. Do I need to have a certified installer; or can I get someone knowledgable to install and then get someone to certify the system for me? 

There is presently no law in South Africa requiring the installer to have some sort of certification. There isn't even an official certification, although there are people trying to start one.

It's best for your own sanity, of course, to choose a good installer

3 hours ago, Rclegg said:

6. Do I need to register NERSA / COJ for the system to be 'legal' 

I believe so, yes.

[Rclegg]

5 minutes ago, plonkster said:

It depends on the peak you need to be supported. I my house we get by on a 3KVA quite easily. Don't ask about brands because we you might as well ask Hilux or Ranger... Everyone knows the Hilux is king, but man... the money!

I will always recommend the 200Ah over the 105 jobbies. Those 105-batteries are meant for UPSes and they are not going to last. I can't say if it is enough to run for 4.5 hours... it depends on your load during that time. Multiply your average load by 4.5 (hours), then multiply that by 2 (so the batteries are only discharged to 50%)... and divide by 50 (just to make the math easy, the battery voltage). So as an example, a 500W load, times 4.5 is 2250, times two is 4500, divided by 50 is a 90Ah battery.

Regardless of whether it is a requirement, put one in anyway. There are times you need to bypass the inverter so you can do work on that side of the system, and the long-haired bipeds don't like it when the power is down.

Regulations require clear separation of backup circuits and non-backup circuits. It is allowed to be in the same board, but the distinction must be clear, and your backup side must have its own RCD, split neutrals, and so forth. Most people run out of space once they have to add the changeover and additional RCD, so they end up with a sub-DB anyway.

There is presently no law in South Africa requiring the installer to have some sort of certification. There isn't even an official certification, although there are people trying to start one.

It's best for your own sanity, of course, to choose a good installer

I believe so, yes.

Thank you so much for assisting. This definitely helps. 

I'll try figure out a way to get the peak loads measurements and go from there. 

Another question if you don't mind: I've been reading on these forums that the PylonTech batteries are also decent (US3000 3.5kWh / 48 V setups. Would I be best saving for this and going this route instead of "run of the mil" 200ah batteries that might only last 3 years and need replacing anyway?

Also, if I were to upgrade to Solar - do I need much else besides panels? 

 

Appreciate the assistance! 

[___]

12 minutes ago, Rclegg said:

Another question if you don't mind: I've been reading on these forums that the PylonTech batteries are also decent (US3000 3.5kWh / 48 V setups. Would I be best saving for this and going this route instead of "run of the mil" 200ah batteries that might only last 3 years and need replacing anyway?

It is hard to say whether you should wait. The irritation is right now, the reward (from a  happy wife) is right now Yes, those Pylontech batteries are excellent value for money and they do last considerably longer, so I do think you will end up there eventually.

My brother in law is approaching this in a similar fashion right now. He wants two things backed up: His internet connection, and the alarm system which for some <insert expletive> reason can't be muted and has to go *BEEEEP* every few seconds to remind you that the power is off.

He is starting with two second-hand 200Ah batteries and a second-hand 24V inverter... and I suspect that over time he will add a few bedlamps, watch a cricket game or two... and then he'll get new batteries

 

[gallderhen]

4 hours ago, Rclegg said:

I'll try figure out a way to get the peak loads measurements and go from there. 

Hi,

 

If you have an Empire Hexing prepaid meter, you can hit 808 + enter to get the power-draw at that very moment (like when the poolpump and the washing machine and the tumble dryer and the geyser is running at the same time).

 

Otherwise try to borrow a power-meter like Efergy or Owl from someone, hook it over the main power cable in your DB and start measuring.

Just know that you only measure over that particular cable, unlike mine where I have 3 DBs distributed on the property and thought that City Power was shafting me 

 

-G-

[Rclegg]

7 hours ago, gallderhen said:

Hi,

 

If you have an Empire Hexing prepaid meter, you can hit 808 + enter to get the power-draw at that very moment (like when the poolpump and the washing machine and the tumble dryer and the geyser is running at the same time).

 

Otherwise try to borrow a power-meter like Efergy or Owl from someone, hook it over the main power cable in your DB and start measuring.

Just know that you only measure over that particular cable, unlike mine where I have 3 DBs distributed on the property and thought that City Power was shafting me 

 

-G-

Thanks, good to know there are relatively easy methods as well as a meter.  

The smart meter I was talking about earlier does do current consumption - eg when I switch the pool pump on, it goes up by 0.7kWh (750w) which is what the pump is rated at. So I think that is accurate enough. 

 

I'll test what peak load is this weekend in a simulated load shedding scenario - ie, just lights and all the plugs with tv, entertainment unit on etc. 

[___]

9 hours ago, gallderhen said:

If you have an Empire Hexing prepaid meter, you can hit 808 + enter to get the power-draw at that very moment (like when the poolpump and the washing machine and the tumble dryer and the geyser is running at the same time).

For a Conlog meter it is #1# (hash one hash).

[Antony]

On ‎2020‎/‎01‎/‎14 at 8:53 AM, plonkster said:

For a Conlog meter it is #1# (hash one hash).

For maximum power display on Hexing press 869 + enter

[Marlonw]

On 2020/01/13 at 3:47 PM, phil.g00 said:

I take that is 30kWh a day, learn the correct units or you'll get bum steers like many have before you.

You shouldn't size for average, you should size for peak.

It isn't enough to know what you use in a day, you'll need to know what your peak usage is in kVA and the peak in kWh (or kVAh) usage over any given 4.5 hour period.

In other words, your loads wont be constant throughout the day, and your maximum demand matters.

So start by recording your  normal usage for a month or so, in a way that you can answer these questions.

Then change your usage patterns, both by reducing usage and by scheduling the loads differently, and record for another month.

Then look at what you need.

 

 

[Rautenk]

@Rclegg,

I think you have a few items to play with. 

I would strongly recommend that once you have gone through the measurement campaign look at doing a Hybrid system. 

The Axpert is nice and cheap and great for back-up, but as per the video once PV becomes involved it is a different story. What the Video does not cover is what happens at load shedding times. That Grid Tied shuts down and only the batteries provide power. Bloody waste in the day! Whereas a true Hybrid will still utilise the PV panels.

Then, I am going to severely disagree with @plonkster on the battery choice. I would AVOID the 200Ah batteries if you want to go over 3kVA. Your Deep Cycle lead acids actually do not like giving high current. So lets say you have a 5kW/kVA system and you switch things on max. Then you need to deliver 100A+ at 48V, batteries just do not like it. Better to go for 8x105Ah to manage the current draw overall. Your batteries will thank you.

But, then again, it is MUCH cheaper(lifetime) to go for lithium at 90% d.o.d than it is to go for 8x105Ah batteries at 30% d.o.d (for if you want it to last 5 years). You actually end up with a very small margin of difference if you compare the 2.4kWh pylon to 8x105Ah deep cycle. And with Lithium advance BMS systems you can actually buy one now and add a few later. quite impressive, this CANNOT be done with Lead Acids, except with expensive electronics (which is included in the Pylon/BYD/SolarMD packages).

With a Hybrid configuration (GoodWe for example, just because I don't want to satisfy the blue guys and say Victron), you will be able to have dedicated back-up circuits (i.e. your plugs and lights) and then the hybrid function will allow you to utilise the PV component for your geyser, stove, etc. Only thing will be that geyser, stove, etc will be off during load shedding.

So summary:

1. Get you PEAK LOAD ( in kW) which you want to connect to your back-up system

2. Use worst case energy usage(kWh) over 3 hours as your required back-up time. (But only estimate with back-up system)

3. plonk got it right, always install a change over switch... you never know if the inverter might go bonkers. It happens, especially with the Axperts (clones)

4. Second DB is advisable and depends who reads the regulations, required. Some inspectors insist that back-up systems be physically separate from main circuits. This is very open to interpretation. 

5. If you go CoJ route then you will probably need someone to certify the system

6. If you add panels later, then you need to make sure that you take into account the Combiner or DC distribution box. You need to have fuses (or DC Circuit breakers) and Surge Arrestors before going into the inverters.   

 

[Marlonw]

1. Separate circuits in a new DB

2. install a bypass/change over switch( less hassle when things go wrong)

3. Lithium & inverter combination - choose carefully. Not all inverters can communicate with the lithium BMS(battery management system) Goodwe 4.6kw is set up for a few different brands of lithium batteries. I recommend it highly. Not lots to tinker with. You can use the app....very simple. 
Off grid inverters are generally better off with gel batteries. Lithium batteries shut off with no output...dramas. some inverters depend on DC from batteries to do switching. No DC No power ...even if grid is available. You then have to reset batteries physically. 
There are third party devices who take care of the comm side, but in my experience rather stick to direct comm devices. These third party devices don’t ‘wake’ the lithium up like direct comm inverters do. 
4. Start with 9 x 330watt panels and at least a 150ah battery (lithium) or 200ah gel. 2.9kw panels will give enough to recharge lithium by 11am and run base load with spare capacity for outages. You have to add batteries later in order to store energy for later use in order to get better savings. 
Gel recharge time is longer( different charge rate) . Lithium makes more sense in the long run though. It trumps gel in most every category (energy density, DOD, cycles, round trip efficiency, cycle life....etc.)

There are new products like Alpha ess smile5, which are modular and has its own batteries....no comm issues . You set DOD and forget about it. Watch this space....Alpha will have a huge market share soon. Check them out. 
Schneider has a similar product as well.

TBB products are good. Direct rivals for Victron and Axperts. TBB is transformer based (toroidal) so efficiency is around 96% or so they claim.

Kodak do inverters now (Solis and Axpert knockoffs)...better software though. 
Solis is good...not too many installed.  

5. Get a seasoned installer. I’ve come across too many botched installations....you’ll end up spending double if you go with a ‘fly by night’ installer. Someone with electrical background and a PV green card can definitely add value rather than cost you.  

6. You need a COC for the electrical. Thus far the regulations for PV is not cast in stone, but I was promised by the SANS guys that we can expect some form of COC for PV by March 2020. 
NB! There is a lot to consider when doing a design. I haven’t even scratched the surface.... 
 

[___]

2 hours ago, Rautenk said:

8x105Ah

Why 8 x 100Ah and not 4 x 200Ah? A good "deep cycle" AGM is good for C/5 discharge (but obviously C/10 is better), and any good AGM is miles better than the semi-sealed 105Ah jobbies.

OK, if you are saying the 100Ah batteries are better for high current loads (at the expense of cycle life), then I agree with you. I tend to focus on cycle life

 

[LPG]

1 hour ago, Pietpower said:

At first I also thought pv on grid tie is a big waste of available energy during the day when you have load shedding.

I have changed my mind now a bit:

Currently I utilise all the PV between 8-11pm to charge the batteries.  Thereafter it runs at reduced load in any case and I waste a lot of PV power.
The times that load shedding also happened between 8-11 are few and overall I don't think I would have lost much.
For the rest of the day I would have only lost the 300-500W of basic load.

What I have done is kept the geyser on the grid tie side of my hybrid inverter and this causes a much longer use of the PV power and better efficiency.
Still have to figure how to do the sums but if I installed a solar water geyser I would reduce daily load by about 8kWh (1/3rd in my case) and get away with less solar panels but I doubt the saving on the PV system would be enough to cover a nice evacuated tube system of say R20k.

 

[LPG]

Hi Rclegg

I grappled with all the questions you have asked for a year before I designed and installed my system.   The answers you have received above are excellent.

Here are some things to think about before making final decisions :- 

1.  Make a list of all your power consumers and estimate / measure their monthly consumption, to understand where your power is going.

2.  Try to reduce your consumption as much as possible :- replace all your light bulbs with energy efficient ones.  Fit a solar geyser (it will pay for itself within 2 yrs).  Assess your fridges and freezers (these are probably the number 3 consumer after your Geyser and Cooker) .  Gas cookers are a good idea but are expensive to buy.  (I use a solar geyser but still use my normal electric stove).

3.  You mentioned that your initial objective is to live without load-shedding and later to upgrade to solar power.  Make sure you go for a system that allows for such an upgrade.  There is a lot of debate about what "Hybrid" and "Grid-Tied" mean.  Read until you understand what the options there are.

4.  See if you can arrange to visit people who have systems installed.  First prize would be a qualified person who did the design and installation themselves and has it up and running.

One question :-  Where do you live?

All The Best

LG

[Rautenk]

14 hours ago, Pietpower said:

hybrid also use battery power to feed the geyser or stove or dishwasher on the grid tie side.  Sizing of pv panels and batteries and setup is important

Hi @Pietpower, very good point. However, this strongly depends on your settings of the inverter. If it is, for example, set to Back-Up mode then the batteries will only be used to support back-up loads during no-grid scenario. 

Another reason to rather go Lithium batteries, this will allow you to basically maximise the use of solar.

ps. Due to adding pieces (and based on cost) I have ended up with:

1x 4.6kW Solis inverter (3.2kWp of panels)

1x Axpert (1.6kWp of panels) connected to essentials 

Axpert has 7-year old lead acids, and getting replaced with lithium ones end of month, at what stage I will take the essentials effectively off-grid. 

The Solis is on grid side, as putting it on the back-up side of the Axpert will most likely make the operating smoke come out the Axpert! 

 

  

[Rclegg]

On 2020/01/15 at 11:55 AM, Pietpower said:

I have a similar kwh daily load at 20kWh with geyser and installed a hybrid system.

Maybe first do some research about the differences between Grid-tied vs Off-grid vs Hybrid

This video helped me a lot to understand it: 

 

 

Great video, thanks for sharing it. It does help!

On 2020/01/15 at 12:06 PM, Pietpower said:

Grid-tied inverter switch off when Eskom goes down thus not a solution for load shedding.

You can use an off-grid inverter now (and split your DB and loads) for immediate load shedding solution at a low cost.
Then later add a Grid-tied inverter and solar panels for energy saving.

Hybrid basically combines a grid-tied inverter and an off-grid inverter with the advantage that you still have solar power during the day with power outages.
It comes at a high cost though.  An advantage is that say a 5kVA can supply 5kVA downsteam and 5kVA upstream.

Or you could install two off-grid inverters (or a large one) and run most of your house from it then manage power usage during load shedding to save battery life.
Double off-grid inverters can cost less than one hybrid inverter.

Batteries I have personally gone with lithium. Maybe buy one now and then another later.
I bought a second one within a few weeks but that was because one battery could not put enough load on the solar panels to maximise savings.

That's a deal breaker then. Did not know that!

So a hybrid system, is what I need then. I am going to go with a 5kVA until as well. As I am sure our usage will go up once the wife and I have kids etc. 

I was considering getting the PylonTech batteries. A 2.5kVa (I think) - I hear they will give me a longer lifetime (like 10 yrs - 6000 cycles?) - and as you say, can start off with one and add later?

On 2020/01/15 at 3:50 PM, Rautenk said:

@Rclegg,

I think you have a few items to play with. 

I would strongly recommend that once you have gone through the measurement campaign look at doing a Hybrid system. 

The Axpert is nice and cheap and great for back-up, but as per the video once PV becomes involved it is a different story. What the Video does not cover is what happens at load shedding times. That Grid Tied shuts down and only the batteries provide power. Bloody waste in the day! Whereas a true Hybrid will still utilise the PV panels.

Then, I am going to severely disagree with @plonkster on the battery choice. I would AVOID the 200Ah batteries if you want to go over 3kVA. Your Deep Cycle lead acids actually do not like giving high current. So lets say you have a 5kW/kVA system and you switch things on max. Then you need to deliver 100A+ at 48V, batteries just do not like it. Better to go for 8x105Ah to manage the current draw overall. Your batteries will thank you.

But, then again, it is MUCH cheaper(lifetime) to go for lithium at 90% d.o.d than it is to go for 8x105Ah batteries at 30% d.o.d (for if you want it to last 5 years). You actually end up with a very small margin of difference if you compare the 2.4kWh pylon to 8x105Ah deep cycle. And with Lithium advance BMS systems you can actually buy one now and add a few later. quite impressive, this CANNOT be done with Lead Acids, except with expensive electronics (which is included in the Pylon/BYD/SolarMD packages).

With a Hybrid configuration (GoodWe for example, just because I don't want to satisfy the blue guys and say Victron), you will be able to have dedicated back-up circuits (i.e. your plugs and lights) and then the hybrid function will allow you to utilise the PV component for your geyser, stove, etc. Only thing will be that geyser, stove, etc will be off during load shedding.

So summary:

1. Get you PEAK LOAD ( in kW) which you want to connect to your back-up system

2. Use worst case energy usage(kWh) over 3 hours as your required back-up time. (But only estimate with back-up system)

3. plonk got it right, always install a change over switch... you never know if the inverter might go bonkers. It happens, especially with the Axperts (clones)

4. Second DB is advisable and depends who reads the regulations, required. Some inspectors insist that back-up systems be physically separate from main circuits. This is very open to interpretation. 

5. If you go CoJ route then you will probably need someone to certify the system

6. If you add panels later, then you need to make sure that you take into account the Combiner or DC distribution box. You need to have fuses (or DC Circuit breakers) and Surge Arrestors before going into the inverters.   

 

Thank you very much for this @Rautenk - very informative. I've started logging usage and this weekend will test peak load in a load shedding scenario. 

On 2020/01/15 at 4:18 PM, Marlonw said:

1. Separate circuits in a new DB

2. install a bypass/change over switch( less hassle when things go wrong)

3. Lithium & inverter combination - choose carefully. Not all inverters can communicate with the lithium BMS(battery management system) Goodwe 4.6kw is set up for a few different brands of lithium batteries. I recommend it highly. Not lots to tinker with. You can use the app....very simple. 
Off grid inverters are generally better off with gel batteries. Lithium batteries shut off with no output...dramas. some inverters depend on DC from batteries to do switching. No DC No power ...even if grid is available. You then have to reset batteries physically. 
There are third party devices who take care of the comm side, but in my experience rather stick to direct comm devices. These third party devices don’t ‘wake’ the lithium up like direct comm inverters do. 
4. Start with 9 x 330watt panels and at least a 150ah battery (lithium) or 200ah gel. 2.9kw panels will give enough to recharge lithium by 11am and run base load with spare capacity for outages. You have to add batteries later in order to store energy for later use in order to get better savings. 
Gel recharge time is longer( different charge rate) . Lithium makes more sense in the long run though. It trumps gel in most every category (energy density, DOD, cycles, round trip efficiency, cycle life....etc.)

There are new products like Alpha ess smile5, which are modular and has its own batteries....no comm issues . You set DOD and forget about it. Watch this space....Alpha will have a huge market share soon. Check them out. 
Schneider has a similar product as well.

TBB products are good. Direct rivals for Victron and Axperts. TBB is transformer based (toroidal) so efficiency is around 96% or so they claim.

Kodak do inverters now (Solis and Axpert knockoffs)...better software though. 
Solis is good...not too many installed.  

5. Get a seasoned installer. I’ve come across too many botched installations....you’ll end up spending double if you go with a ‘fly by night’ installer. Someone with electrical background and a PV green card can definitely add value rather than cost you.  

6. You need a COC for the electrical. Thus far the regulations for PV is not cast in stone, but I was promised by the SANS guys that we can expect some form of COC for PV by March 2020. 
NB! There is a lot to consider when doing a design. I haven’t even scratched the surface.... 
 

Thanks @Marlonw - the Goodwe 4.6kw looks really good. However out of mu budget right now. Will something like the RCT 5000 or the Mecer ones work? And then perhaps I can upgrade it at a later stage?
also Where does one shop for panels? 
 

23 hours ago, LPG said:

Hi Rclegg

I grappled with all the questions you have asked for a year before I designed and installed my system.   The answers you have received above are excellent.

Here are some things to think about before making final decisions :- 

1.  Make a list of all your power consumers and estimate / measure their monthly consumption, to understand where your power is going.

2.  Try to reduce your consumption as much as possible :- replace all your light bulbs with energy efficient ones.  Fit a solar geyser (it will pay for itself within 2 yrs).  Assess your fridges and freezers (these are probably the number 3 consumer after your Geyser and Cooker) .  Gas cookers are a good idea but are expensive to buy.  (I use a solar geyser but still use my normal electric stove).

3.  You mentioned that your initial objective is to live without load-shedding and later to upgrade to solar power.  Make sure you go for a system that allows for such an upgrade.  There is a lot of debate about what "Hybrid" and "Grid-Tied" mean.  Read until you understand what the options there are.

4.  See if you can arrange to visit people who have systems installed.  First prize would be a qualified person who did the design and installation themselves and has it up and running.

One question :-  Where do you live?

All The Best

LG

Hi @LPG I'm in Randburg, Johannesburg. 
Thanks for the info - I'll add your points to my list as well for this weekend to see what is needed and used etc. 

Seems its a hybrid system I want not a grid-tied setup. I will do more research into it. 

 

Thanks to everyone who has replied and given feedback / advise. I appreciate it hugely. 
I will update the thread next week once I have worked out the devices I need on and the max peak load we need to sustain during load shedding.

[___]

2 hours ago, Pietpower said:

The Goodwe is a hybrid at about R30k.  I think most of your hybrids will be around there.

Yup, I've often remarked that the comparison that is always done around here, which is to compare  the Voltronic with other brands, is a little unfair, because the Voltronic is (comparatively speaking) ridiculously cheap. The moment you go one notch up from there, they are all in the same sort-of neighbourhood with 10% to maybe 20% separating them.

[Peter Topp]

Hi

At the end of 2016 I invested in an Axpert 5k system with 4x 180ahr 12v batteries and a manual changeover switch which was extremely reliable. I added a second Axpert later so that I could increase my max load to 8Kw and run power through the inverters. I use a gas geyser and stove.

I then added 12x 255w solar panels to the mix. I found that I had not done enough research to get the most out of my pv panels. As the video shows the pv panel power does not blend in with the main power and switching occurs between mains power and pv power in the axpert hybrid setup.

I eventually replaced my 2x axpert units to a grid tied unit and increased my pv panels to 24x 255w (6.12Kw). This was to get the most out of my investment on pv panels. A grid tie unit integrates the pv power with mains seamlessly without switching. You do not have to put power back into the grid. I also now have replaced my batteries with 4 x 48v 100ahr Li batteries. I get about 15Kwh - 40Kwh a day from my pv panels.

I cannot give you any advice on a grid tied inverters as I have had many problems which you read from my other posts. I now run with a single 5Kw grid tied unit and make sure I do not use two heating devices at once. ( kettle and oven or iron etc.). 

If you are considering adding pv panels I would suggest you look into the switching problems with a axpert hybrid before deciding on a inverter. 

 

[___]

1 hour ago, Pietpower said:

Which grid tie inverter do you have that has the option to add batteries?

Any hybrid inverter can do that. Goodwe and Victron are two that can (tie battery with grid).

[Peter Topp]

I have a Infinisolar Plus 5K hybrid grid tied inverter which also allows up to 10Kw of pv panels.

[___]

2 hours ago, Pietpower said:

I suppose definitions are not exact.

Yup. In my experience the term "hybrid" got hijacked at some point.

Hybrid normally means a thing made by combining two or more other things. In this context, it means an inverter that combines the grid-tie ability of a PV-inverter (this is the name Victron uses to avoid confusion) with the backup capabilities of a battery inverter.

Then a few months later I saw someone advertise an Axpert as a Hybrid. Upon investigation, I found the reason for that is that it combines a solar charger and an inverter into one unit.

Roll on many years later and many people insist that the Victron inverters are not hybrids (they are) but that the Axpert is!

Talk about an inversion of meaning!

Edit: Just to add, the Infinisolar is indeed a hybrid. It ties with the grid like a PV-inverter, but it also has battery backup.

Edited January 20, 2020 by plonkster