Morning, starting on this confusing journey!

I am close to installing a 5kw Sunsynk with a 5kw Sunsynk battery, with about 3.7kw PV. I have asked the question below to various installers and get various answers.

I want to split up my home items between:

Essential:
All lights and plugs inside the house

Non-Essential:
Swimming pool pump
Oven
Geyser


So my question, which applies to when there is NO load-shedding....

Some installers lead me to believe that when your home items (essential and non-essential items) are switched on and use more than 5kw in total, then the inverter will trip?
Others say no, that wouldn't happen, as the excess usage will be sourced from Eskom. So if you where to use for example a total of 7kw on your essential and non-essential items, 3kwh would theoretically be sourced from your solar panels, 3kw would theoretically be sourced from your battery but together it will be limited to 5kw due to inverter limitation being 5kw, and the remainder of 1kw will be sourced from Eskom?

So which one is correct?

Thanks!!

Edited December 4, 20223 yr by cecilh

Excess will be sourced from Eskom. Non-essentials generally use eskom unless you setup your CT and settings to export solar to them.

Inverter will trip if load on essentials is greater than 5kw during LS or greater than 7.5kw when there is no LS (35A pass through)

14 minutes ago, cecilh said:

So which one is correct?

If wired correctly, your non-essentials remain on your 'main' DB board and hence are wired before your inverter. Any power draw from them does not go through your inverter - which means does not impact the 5kW that your inverter can provide on the output side. Your essentials are connected to the output side of the inverter, which are restricted to 5kW of loads during loadshedding and have a 35A pass-through capability for access loads while the grid is present. I have to admit that I do not know though if this 35A pass-through is total load (as @mzezman wrote) or in addition to the 5kW inverter capacity. Maybe @Leshen can advise please?

The beauty of the Sunsynk is that it is a bi-directional inverter - which means it can not only draw power through the AC Input, but also push back power through it. This means, that (if your CT coil is correctly installed) when it has access PV available (meaning when your available PV is higher than your essential load) it can push power back to your non-essentials. Hence your non-essentials can also be supplied by PV, reducing your grid draw. If your non-essential load is higher than your excess PV, it will take the balance from the grid. However, this will only work while the grid is present - so not during loadshedding.

32 minutes ago, cecilh said:

So if you where to use for example a total of 7kwh on your essential and non-essential items, 3kwh would theoretically be sourced from your solar panels, 3kwh would theoretically be sourced from your battery but together it will be limited to 5kwh due to inverter limitation being 5kw, and the remainder of 1kwh will be sourced from Eskom?

Assuming that your essential load does not make up more than 5kW of your 7kW load (not kWh - different thing 😉), it will most definitely not trip your inverter but rather:

• If your inverter settings do allow you to draw from batteries (SOC higher than target SOC):
  It will provide a total of 5kW from your PV and batteries to both your essentials and non-essentials and take the 2kW shortfall for the non-essentials from grid
• If your inverter settings do not allow you to draw from batteries (SOC lower than target SOC):
  It will provide whatever load is present on your essentials and use the remaining PV to charge your batteries. Non-essentials will be completely powered by grid
  (I have to admit I am not 100% sure on this. I cannot exactly recall as I no longer have anything connected to non-essentials) 

9 hours ago, cecilh said:

So if you where to use for example a total of 7kw on your essential and non-essential items, 3kwh would theoretically be sourced from your solar panels, 3kw would theoretically be sourced from your battery but together it will be limited to 5kw due to inverter limitation being 5kw, and the remainder of 1kw will be sourced from Eskom?

If your total load is 7kw, and your panels supply 3kw, the battery will only supply 2kw as the limitation is 5kw. The other 2kw will be supplied from Eskom. There is no limitation on the non essential circuit and there is a maximum of approximately 8kw (5kw DC to AC) (3kw from Eskom) limitation on the essential circuit when Eskom is available and 5kw when Eskom isn’t available. The issue with using more than 5kw on the essential is if Eskom goes offline at that instant, the inverter will shutdown due to AC overload fault. 

Thank you!

Hi, It is a awesome inverter and works great with powering none essential loads with spare PV. Lots of configurable power priorities and mode variations. Easy to configure diffrent modes.

Its been the best inverter that I have had so far. Definitely a good investment.

15 hours ago, Sonoff Africa said:

Its been the best inverter that I have had so far. Definitely a good investment.

Totally agree with you on this, a great piece of kit especially with the Eskom issues. 👍

Hi Cecilh. I installed a 5kw Revov battery(said to be the best) and a growatt inverter. I can only use the lights plugs tv and fridges. No oven washing machine or tumble dryer or geyer0. That is with load shedding. When power is restored your appliances will work normal with escom power. But 3.5kw is not enough to power your whole house. And when the battery goes dead three times(totally empty) you can throw it away R29 000.00. Even if it has a 10year gaurentee.So be careful when you go on holiday and the battery runs down. Or any other time.

I Guess it all comes down to the capability of the Inverter.

To achieve a blend of Eskom and Solar you will require a hybrid inverter ie. Sunsynk and Deye.

From personal experience, When eskdom is on and I draw more than what my inverter is capable of supplying, Then it sources the difference from eskdom.

 

On the essential side we have never drawn more than 4.5kw.

With essential and non essential load combined we have topped 9.1kw twice since going solar. We have however optimized our system accordingly to prevent it from happening to eventually go off grid 2023. Soon everything will be connected to the essential side and aux port for heavy load items ie geyser, oven.

 

5 hours ago, nicole6 said:

Hi Cecilh. I installed a 5kw Revov battery(said to be the best) and a growatt inverter. I can only use the lights plugs tv and fridges. No oven washing machine or tumble dryer or geyer0. That is with load shedding. When power is restored your appliances will work normal with escom power. But 3.5kw is not enough to power your whole house. And when the battery goes dead three times(totally empty) you can throw it away R29 000.00. Even if it has a 10year gaurentee.So be careful when you go on holiday and the battery runs down. Or any other time.

We have a growat and Narada battery with 4.6kw panels. I do washing during the day. Tumble dryer and dishwasher during loadshedding. Without any problems

On 2022/12/20 at 5:41 AM, nicole6 said:

Hi Cecilh. I installed a 5kw Revov battery(said to be the best) and a growatt inverter. I can only use the lights plugs tv and fridges. No oven washing machine or tumble dryer or geyer0. That is with load shedding. When power is restored your appliances will work normal with escom power. But 3.5kw is not enough to power your whole house. And when the battery goes dead three times(totally empty) you can throw it away R29 000.00. Even if it has a 10year gaurentee.So be careful when you go on holiday and the battery runs down. Or any other time.

Hi, the Sunsynk inverter has a table that will ensure that the SOC never goes below the level at any specified times.

On 2022/12/20 at 5:41 AM, nicole6 said:

 And when the battery goes dead three times(totally empty) you can throw it away R29 000.00. Even if it has a 10year gaurentee.So be careful when you go on holiday and the battery runs down. Or any other time.

Any reference to this. I thought that's why there is a BMS to cut the battery to OFF state. 

This to me is the major plus of lithiums. 

Edited December 21, 20223 yr by Scorp007

Hi Everyone. I'm now really confused. I own a Growatt SPF 5000 ES 5kVA inverter and my understanding is that it's not a bi-directional inverter. I contacted my supplier and they told me it is! Could someone with more knowledge please confirm this.

Thanks everyone.

2 minutes ago, Kevin52 said:

Hi Everyone. I'm now really confused. I own a Growatt SPF 5000 ES 5kVA inverter and my understanding is that it's not a bi-directional inverter. I contacted my supplier and they told me it is! Could someone with more knowledge please confirm this.

Thanks everyone.

What do you mean bi-directional inverter? 

1 hour ago, Antonio de Sa said:

What do you mean bi-directional inverter? 

It's where the inverter will supply excess power from you solar panels back to your DB board. In this situation, your none essential loads can receive power from the grid and the inverter.

I think your definition of a bi-directional inverter is debatable. Compare for example the Microcare bi-directional inverter https://microcare.co.za/products/pure-sine-wave-bi-directional-inverters/ which is a charger and inverter in one, and can run power in and out of a battery, as opposed to a stand-alone charger or inverter. The Growatt will indeed work like this. However it is not a grid-tied inverter, which is what you seem to be referring to. Don't want to argue definitions, just saying that you and the supplier might be talking past each other while each thinks he is correct.

Thanks for the response. I'm no expert in this so I guess terminology could be an issue. Let me rephrase the question; Leading from the discussion in this thread, I would like to know if the Growatt can supply excess power generated from the solar array, back to the DB board so that this power can be used for none essential loads. My supplier stated that all bi-directional inverters perform this function and that was the definition of 'bi-directional'. I was under the opinion that the Growatt SPF 5000 ES 5kVA inverter was actually an off grid system and therefore did not feed back excess power to the DB board. I just would like to know if the Growatt can feed excess power back to the DB board.

11 hours ago, Kevin52 said:

Thanks for the response. I'm no expert in this so I guess terminology could be an issue. Let me rephrase the question; Leading from the discussion in this thread, I would like to know if the Growatt can supply excess power generated from the solar array, back to the DB board so that this power can be used for none essential loads. My supplier stated that all bi-directional inverters perform this function and that was the definition of 'bi-directional'. I was under the opinion that the Growatt SPF 5000 ES 5kVA inverter was actually an off grid system and therefore did not feed back excess power to the DB board. I just would like to know if the Growatt can feed excess power back to the DB board.

My apology for the long winded explanation, I hope it helps. My installation is Canadian Solar, Victron Multiplus Inverter and Freedom Won storage. In terms of application I would think these things are pretty standard. Standard configuration is for essential circuits to run regardless of Eskom. Ideally, there should be sufficient capacity in both PV and battery to be off grid  which of course is frightfully expensive. Hence the “Self consumption” configuration like mine, which manages important loads during grid failure.

Come darkness and whilst Eskom is online (but PV is sleeping), the inverter feeds both essential and non-essential circuits, until battery reaches the preset discharge level (mine’s at 50%) then the feed for the non-essential circuits is disconnected and essential circuits only are powered. This will last until the battery fully discharges or reaches lowest state of charge setting (mine is 20%) and will then disconnect everything.

Come sunlight and Eskom is online, the system will focus on charging the battery, whilst drawing on Eskom for both essential and non-essential circuits. As the battery fills up, the system will start sharing PV to total loads and battery charging. When the battery is full, the system will focus the PV to the total load and borrow from the battery. Technically, for few hours a day, the system runs “off grid”.

During loadshedding, feed to non-essential circuits are disconnected, only essential is fed until the battery reaches total discharge as above.

During loadshedding and sunlight, essential circuits only are fed and the battery is charged. The inverter then will balance drawdown from the PV and battery, ideally to charge the battery whilst feeding the essential circuits. If the essential circuits load exceeds the PV capacity, inverter will use max PV and draw from the battery, until the battery reaches discharge preset and all is disconnected. Note, during loadshedding, excess PV capacity will not be fed to non-essential loads. Non-essential circuits are fed only when Eskom is online. Maybe this clarifies your question?

Edited December 22, 20223 yr by Cory

1 hour ago, Kevin52 said:

Thanks for the response. I'm no expert in this so I guess terminology could be an issue. Let me rephrase the question; Leading from the discussion in this thread, I would like to know if the Growatt can supply excess power generated from the solar array, back to the DB board so that this power can be used for none essential loads. My supplier stated that all bi-directional inverters perform this function and that was the definition of 'bi-directional'. I was under the opinion that the Growatt SPF 5000 ES 5kVA inverter was actually an off grid system and therefore did not feed back excess power to the DB board. I just would like to know if the Growatt can feed excess power back to the DB board.

For the sake of terminology, let's say that you want to export power like the typical full hybrid like Sunsynk, Deye, Infinisolar, or Goodwe or maybe a Victron.

The Growatt does not do this. It's good for some other reasons, but this is not it.

My 2c. But best to confirm with someone that actually has one.

*

Edited December 21, 20223 yr by yousuf2217
didn't quote properly

23 minutes ago, Cory said:

My installation is Canadian Solar, Victron Multiplus Inverter and Freedom Won storage. In terms of application I would think these things are pretty standard. Standard configuration is for essential circuits to run regardless of Eskom.

Come darkness and whilst Eskom is online (but PV is sleeping), the inverter feeds both essential and non-essential circuits, until battery reaches the preset discharge level (mine’s at 50%) then the feed for the non-essential circuits is disconnected and essential circuits only are powered. This will last until the battery fully discharges or reaches lowest state of charge setting (mine is 20%) and will then disconnect everything.

During loadshedding, feed to non-essential circuits are disconnected, only essential is fed until the battery reaches total discharge as above.

During loadshedding and sunlight, essential circuits only are fed and the battery is charged. The inverter then will balance drawdown from the PV and battery, ideally to charge the battery whilst feeding the essential circuits. If the essential circuits load exceeds the PV capacity, inverter will use max PV and draw from the battery, until the battery reaches discharge preset and all is disconnected. Note, during loadshedding, excess PV capacity will not be fed to non-essential loads. Non-essential circuits are fed only when Eskom is online. Maybe this clarifies your question?

So Cory, just on your last point - is there a way to manually direct excess PV to the non-essentials when there is loadshedding? (like an "over-ride" setting of sorts)
I'm planning on doing a Sunsynk inverter install next month, so just curios.

yousuf2217, you could put non-essentials on the Aux output of the Sunsynk. You would probably need a bigger inverter, more batteries and it may interfere with your normal solar harvesting.

10 hours ago, yousuf2217 said:

So Cory, just on your last point - is there a way to manually direct excess PV to the non-essentials when there is loadshedding? (like an "over-ride" setting of sorts)
I'm planning on doing a Sunsynk inverter install next month, so just curios.

Yes, but not through inverter settings. You could do your installation as usual, with separate changeover manual switching.

Personally, I have a sub-DB panel where I can select Eskom or the inverter for either essential or non essential circuits. So it gives some flexibility. See the pic of my sun-DB.

What you can do is to add another three way changeover after the non-essential isolator. There you select either the essential or non-essential isolator to feed to the non-essential circuits.

Note that you will under that configuration effectively select the entire installation to become “off grid” during loadshedding. If so, be sure to keep an eye on the loads as it may unexpectedly drain the battery if the sun clouds over.

If you want to go smart, you can do the latter switching through a coupe of electric relays and a toggle switch.  Add to that a remote network switch and control it from an app like Smart Life. But as I alluded to, your system may be sized ito capacity to isolate the non essentials during loadshedding. So be sure to not overload it.

Ohh ok, makes much more sense then having a Sub-DB like you have (to manually manage it) - appreciate the advice

4 hours ago, Maru said:

I have Luxpower eco hybrid SNA500 inverter which is considered an offgrid inverter. It has  the capability of sending power back to the grid (export) and suppling non essential loads. The only issue is that there is no CT like "true" hybrid models so it works with old energy meters and not the prepaid ones. You can check your manual and settings on Growatt as it may have similar capability. I just don't use this function as I don't have a bidirectional energy meter. 

A bidirectional inverter has one power chain that is capable of  power flow in both directions, ie., the same chain charges a battery from grid, and the same chain can produce ac power from pv and battery, but obviously not simultaneously. 

This neccassarily means the inverter output is connected to both load output and grid, which by definition constitues a grid-tie. But unlike true gridtie like sunsynk, offgrid  inverters like Axpert, Growatt does not allow exporting of power onto the grid. Therefore it is not equipped with ct coil or energy meter connections.   These inverters also allow the powerfull feature of ac blending with the dc power sources. 

I would like to believe that all modern inverters are bidirectional, as it provides ac blending, and remove the need for seperate charging components which includes an extra large transformer.

So essentially the modern offgrid inverter is bidirectional, is gridtied, but exporting is constrained within the bounds of its designated load output. 

 

Edited December 31, 20223 yr by BritishRacingGreen