32 minutes ago, Stanley said:

In grid-tied inverter terminology, islanding is a bad thing. If the grid fails, but the inverter doesn't detect the grid loss and continues to energize the lines

on it's AC input, then it is said to be islanding (or creating an island). This is not allowed, and so inverter manufacturers have to employ several different

methods of detecting this situation so that they can disconnect from the grid and prevent the creation of an island.

Yes I am aware of not feeding back to the grid if the grid is down.........but without batteries I'd like to retain PV output to my loads.

45 minutes ago, Jakes Louw said:

Yes I am aware of not feeding back to the grid if the grid is down.........but without batteries I'd like to retain PV output to my loads.

Unfortunately that is not possible without batteries. You could use a backup generator and the let the PV inverter connect to the generator output but then you need to control the PV production based on the generator load to make sure that you never feed back into the generator because that can damage it.

48 minutes ago, Buyeye said:

This is the island you are looking for.

https://www.sustainable.co.za/sma-sunny-island-8-0h-12-inverter.html

Those are rather expensive, but I agree he needs a battery inverter and batteries. I would recommend one of the MLT products.

The price list can be found here: https://www.mltinverters.com/pricelist.html

Since the OP has AC coupled PV already, the Oasis would probably work well as a UPS that supports having grid-tied inverters on it's output. He must just choose one that is of equal size or greater than his PV inverter. The Oasis 10H is quite a lot cheaper than the SMA 8.0

Welcome to the rabbit hole.

 

7 minutes ago, PaulinNorthcliff said:

Welcome to the rabbit hole.

 

I'm currently paying over R9k per month for power, I'm willing to explore any hole..........

On 03/02/2021 at 8:58 AM, Jakes Louw said:

Busy with planning my grid tie system. Looking at around 15kW 3ph, no batteries, probably dual MPPT minimum. 

While I have somebody's attention: is there a list of forum approved online shops anywhere?

 

 

Have you tried the Powerforum-store? They worked great for me!😀

21 minutes ago, Chloe said:

Have you tried the Powerforum-store? They worked great for me!😀

I'll have a look............

16 hours ago, Jakes Louw said:

I'm currently paying over R9k per month for power, I'm willing to explore any hole..........

Aaaand... with NERSA bending over for EKSDOM that's about to get much worse.

So... many moons ago I used to know a Jakes Louw from De Wildt who dabbled with another form of money pit known as a Land-Rover. Any chance you're related?

59 minutes ago, PaulinNorthcliff said:

Aaaand... with NERSA bending over for EKSDOM that's about to get much worse.

So... many moons ago I used to know a Jakes Louw from De Wildt who dabbled with another form of money pit known as a Land-Rover. Any chance you're related?

That's me. Moved on to Wranglers, much happier now.........😀

6 hours ago, Jakes Louw said:

That's me. Moved on to Wranglers, much happier now.........😀

as in Jeep (Just empty every pocket) ? 😉
I run single phase grid tied and when Eksdom dies I still have electron flow, but I do have some batteries to allow for this, but the batteries wouldn't allow for non-solar (after dark) power other than 2 or 3 minutes... (4 X 170Ah Lead Acid 16 year old batteries that don't have much/any life left...) If, of course, there is a major current draw spike, whilst Eksdom's down during the day, then the batteries aren't enough to prevent the inverter from shutting down.

I guess, what I m trying to state is that if you go for inverters that can run off batteries (but don't have to, like the Sunsynk) then you have options available that don't need to pull a Jeep on you 🙂

Edited February 5, 20215 yr by Kalahari Meerkat
speeling fix :-)

6 hours ago, Jakes Louw said:

That's me. Moved on to Wranglers, much happier now.........😀

Yeah, Land-Rovers select their owners. There is no shame in failing selection ;-{>}

54 minutes ago, Kalahari Meerkat said:

as in Jeep (Just empty every pocket) ? 😉
I run single phase grid tied and when Eksdom dies I still have electron flow, but I do have some batteries to allow for this, but the batteries wouldn't allow for non-solar (after dark) power other than 2 or 3 minutes... (4 X 170Ah Lead Acid 16 year old batteries that don't have much/any life left...) If, of course, there is a major current draw spike, whilst Eksdom's down during the day, then the batteries aren't enough to prevent the inverter from shutting down.

I guess, what I m trying to state is that if you go for inverters that can run off batteries (but don't have to, like the Sunsynk) then you have options available that don't need to pull a Jeep on you 🙂

That's hybrid though, not grid-tied

 

2 minutes ago, Speedster said:

That's hybrid though, not grid-tied

 

It may be called a hybrid inverter, but it is grid tied, in that it takes power from the grid if the need arises, but will keep on powering the home when the grid disappears, if the solar end + batteries can provide enough power, of course, usually that is fine and works, but when Eksdom dies at 11 at night, then power disappears promptly as well.

The original poster wanted grid tied, this makes little sense long term though, unless these inverters cost very little, which I don't think they do, thus, going for a hybrid inverter that can essentially do the same and then some, would make more sense, in my opinion.

1 hour ago, Kalahari Meerkat said:

It may be called a hybrid inverter, but it is grid tied

It is a bit confusing - the class of inverter called "grid-tied" could have been called "grid-export" and it would have been clearer.  Essentially these are inverters that are designed to export excess energy to the grid, and are hence subject to strict regulations as they could make live an utility line on which somebody is working.  They generally use the grid as their "heartbeat" - if the grid goes down, so do they.

All other inverters have provision for connection to the grid (or a generator) to supplement power when PV is insufficient.  These are "off-grid" inverters and they cannot export to the grid - the grid is input only and is used to charge the batteries or support the load directly . 

Hybrid inverters generally means an inverter that can blend power from different sources.  To be fair, Google it and you will find many different "definitions".

 

1 hour ago, Kalahari Meerkat said:

It may be called a hybrid inverter, but it is grid tied, in that it takes power from the grid if the need arises, but will keep on powering the home when the grid disappears, if the solar end + batteries can provide enough power, of course, usually that is fine and works, but when Eksdom dies at 11 at night, then power disappears promptly as well.

The original poster wanted grid tied, this makes little sense long term though, unless these inverters cost very little, which I don't think they do, thus, going for a hybrid inverter that can essentially do the same and then some, would make more sense, in my opinion.

As Calvin mentioned it is hybrid as it can function as both grid-tied and off-grid. Grid-tied inverters can only function if there is an active grid connection, they are unable to provide any power if the grid is down. 

Edited February 5, 20215 yr by Speedster

1 hour ago, Speedster said:

As Calvin mentioned it is hybrid as it can function as both grid-tied and off-grid. Grid-tied inverters can only function if there is an active grid connection, they are unable to provide any power if the grid is down. 

And the most significant aspect of grid tie inverters is they do not have batteries.

While a grid tied inverter may seem cheaper initially our grid is so unreliable that later on you will want to add a battery which might require a new inverter. 

 

You could just get a hybrid inverter at the beginning and add the batteries later.

Edited February 5, 20215 yr by Buyeye

Grid tie inverters have been superseded by hybrids. These are more flexible with storage capacity.

The idea of grid tie was that the grid served as your battery. This was a great idea but the utilities had a problem with this (which I still haven't fully fully understood) So now they have all sorts of criteria if yo want to export to the grid, so much so that it just isn't worth it!

1 hour ago, Richard Mackay said:

Grid tie inverters have been superseded by hybrids. These are more flexible with storage capacity.

The idea of grid tie was that the grid served as your battery. This was a great idea but the utilities had a problem with this (which I still haven't fully fully understood) So now they have all sorts of criteria if yo want to export to the grid, so much so that it just isn't worth it!

Their problem is the what's known as the duck curve. 

Basically pv generation drops steeply requiring the grid to ramp up fairly quickly to meet demand. This causes strain on the grid. This only really happens with grid tied without battery systems. Having batteries reduces this effect as not everyone's batteries would run empty at the same time. 

I'm not convinced! There has been ZERO encouragement to encourage the use of solar PV from the utilities. (In fact they look like they are actively discouraging it!)

Check out this article on what some other countries have done: https://www.economist.com/technology-quarterly/2021/01/07/how-governments-spurred-the-rise-of-solar-power