Hi All, new to the forum and looking at (finally) installing a small 5kw solar system.

My installer (also a friend) has given me a few quotes including options from Sunsynk and Sungrow.

The Sunsynk system is R25k cheaper than the Sungrow (which comes down to the 9,6kwh battery it seems that comes with the Sungrow - Sunsynk is a 5kwh).

Although he has installed many Sunsynks and hasn't had any problems, he has warned me about their appalling aftersales support - hence me joining the forum to try and do some research.

I don't really need such a big battery as the main purpose of the system is to save on Eskom charges so my questions are:

• is Sunsynk still a viable option?

• Are there any alternative recommendations to the Sungrow? Can't really afford the extra R25k.

TIA for any input.

19 minutes ago, Dale.Tucker said:

I don't really need such a big battery as the main purpose of the system is to save on Eskom charges so my questions are:

Nobody at Eskom has said that load shedding is over, and it's pretty clear that things are going to get tight come winter. So you might yet be glad to have that much battery.

Also if you get it charged during the day and then get through the night on the battery, then that's power you didn't have to draw from the grid.

4 hours ago, Bobster. said:

Nobody at Eskom has said that load shedding is over, and it's pretty clear that things are going to get tight come winter. So you might yet be glad to have that much battery.

Also if you get it charged during the day and then get through the night on the battery, then that's power you didn't have to draw from the grid.

Good point.

What are the recommended brands now that installers are using?

1 hour ago, Dale.Tucker said:

Good point.

What are the recommended brands now that installers are using?

Deye which is identical to Sunsynk and out of the same factory with far better support.

Solis 6kw for the best support as they provide a replacement unit and ship your inverter back to China for repairs.

Just look at what sellers that have been in the Solar sector for say 5yrs selling.

Then there are the rebranded Deye/Sunsynk under many names.

Sunsynk has grown beyond the support they can give, or so it seems.

Most forums are littered with the appalling after sales support, I had to make the same decision not so long ago.

I ended up going for a Solis, and have been extremely happy with the support. Their turnaround time on emails is always same day.

21 hours ago, Dale.Tucker said:

Hi All, new to the forum and looking at (finally) installing a small 5kw solar system.

My installer (also a friend) has given me a few quotes including options from Sunsynk and Sungrow.

The Sunsynk system is R25k cheaper than the Sungrow (which comes down to the 9,6kwh battery it seems that comes with the Sungrow - Sunsynk is a 5kwh).

Although he has installed many Sunsynks and hasn't had any problems, he has warned me about their appalling aftersales support - hence me joining the forum to try and do some research.

I don't really need such a big battery as the main purpose of the system is to save on Eskom charges so my questions are:

• is Sunsynk still a viable option?

• Are there any alternative recommendations to the Sungrow? Can't really afford the extra R25k.

TIA for any input.

The same question was asked on facebook yesterday. I only have a link for the group but look for the post: https://www.facebook.com/groups/1224829628388092

Basically the consensus I took away is:

Great product - Failure rate seems high but only because of the volume they have sold and because of the slow support/repairs when there is a failure which results in more people being vocal which is fair

Thanks so much for all the replies!

Decisions Decisions Decisions

I would recommend deye inverter with deye batteries. You'll get a 10 year warranty with the combo, so no stress.

As mentioned above it's the same thing as Sunsynk, but the oem with an arguably better service centre.

Failure rate is low. But with the high percentage of installs using them, there will obviously be a lot mentioned on forums etc.

5 hours ago, rj4 said:

Great product - Failure rate seems high but only because of the volume they have sold and because of the slow support/repairs when there is a failure which results in more people being vocal which is fair

Failure rate could also include all those that have problems due to wrong settings. We just have to see how many questions are asked where CT that is well spelled out is connected the wrong way round. Documentation is sometimes to be blamed.

Did you have a look at Luxpower inverters?

over a month and a half for sunsynk to fix a BMS port on a 7 month old 8kw inverter. my installer was a champ and loaned me a Deye.

It did the same job as the sunsynk, only difference is I use solarassist and home assist, Deye did miss a lot of the commands sent to it from solarassist.

Thanks for all the input. Seems like Sunsynk not an option!

I would go for Sunsynk

I would also not bother with a 5 kW

I would use a minimum of 8 kW to get the savings

Generally can put the whole house on the 8 and feed back to stove and geyser

Much better software than Deye gives more savings

I have installed many

Had one failure

Turnaround time to repair was exactly 21 days

I suspect that quite a few of those days was my supplier in Cape Town delaying shipping to Johannesburg and again collection in Johannesburg and shipping back to Cape Town

I generally feel that the software is much better than Deye and this helps to give maximum savings

Remember to size the inverter for the maximum pass through current if you want to get maximum savings

I very much enjoy the sunsynk software.

5kW still going strong!

J

5 hours ago, James 1 said:

I would go for Sunsynk

I would also not bother with a 5 kW

I would use a minimum of 8 kW to get the savings

Generally can put the whole house on the 8 and feed back to stove and geyser

Much better software than Deye gives more savings

I have installed many

Had one failure

Turnaround time to repair was exactly 21 days

I suspect that quite a few of those days was my supplier in Cape Town delaying shipping to Johannesburg and again collection in Johannesburg and shipping back to Cape Town

I generally feel that the software is much better than Deye and this helps to give maximum savings

Remember to size the inverter for the maximum pass through current if you want to get maximum savings

What's the difference apart from the phone app?

The settings on the inverter are essentially the same as the deye. At times different wordings. Impossible for one to give more savings than the other since it's the same thing.

Deye as the manufacturer you get direct access to their engineers working on the actual firmware etc if there's an issue. Sunsynk is a middle man.

Nevertheless both are good. No issues either way. Deye service centre is definitely faster than Sunsynk though at the moment.

Whichever you choose, it's a great product, comfortably amongst the best.

Edited April 7Apr 7 by abd7

Deye and SunSynk are both excellent pieces of hardware, differentiated by branding and firmware. I personally enjoy the SunSynk firmware, but that is personal taste.

The failure rate has been quotes at 0.4% for SunSynk, but with a large installed base this reflects as "more" failures than other brands.

I have had my SunSynk 8.8 kW machine for a number of years now, and have never had it fail unexpectedly.

Once it did shut-down, but the reason was expected, and no damage to the inverter or household appliances.

What happened is there was a municipal Neutral failure which caused over 300V between Live and Earth, I have SPD's on AC incoming and Essential Load after the inverter.

The SPD on Essential Load fired and shorted to Earth, which caused the inverter to shut-down.

Walking into the power room and smelling that acrid electrical burnt smell sends shivers down the spine. 😕

Once the fault was diagnosed, municipal power was disconnected, the damaged SPD replaced, the inverter booted up with no problem and ran on batteries for the night.

One tough "sun of a gun", so I am happy with my machine. Also I have passed through well over 10 kW.

14 hours ago, James 1 said:

I would go for Sunsynk

I would also not bother with a 5 kW

I would use a minimum of 8 kW to get the savings

Generally can put the whole house on the 8 and feed back to stove and geyser

Much better software than Deye gives more savings

I have installed many

Had one failure

Turnaround time to repair was exactly 21 days

I suspect that quite a few of those days was my supplier in Cape Town delaying shipping to Johannesburg and again collection in Johannesburg and shipping back to Cape Town

I generally feel that the software is much better than Deye and this helps to give maximum savings

Remember to size the inverter for the maximum pass through current if you want to get maximum savings

Respectfully disagree on one or two points, open to correction.

As was pointed out, Sunsynk and Deye have the same hardware and functions, so the improved software is not necessarily indicative of greater savings.

Also, why would a greater pass-through current lead to greater savings? The greater pass-through is what allows you to use more GRID POWER on your essential loads, which is great if you need it, but where is the saving?

It just sounds like "maximum savings" is a catch-all phrase to say why bigger is better, without analysing the user's needs and situation.

9 hours ago, abd7 said:

Impossible for one to give more savings than the other since it's the same thing.

If they are the same hardware but have different firmware then they could perform differently.

Any Goodwe owner will tell you about getting a firmware update and then finding your system behaving diferently.

9 hours ago, Bobster. said:

If they are the same hardware but have different firmware then they could perform differently.

Any Goodwe owner will tell you about getting a firmware update and then finding your system behaving diferently.

Deye makes the firmware for Sunsynk, and the deye employees do the software updates for Sunsynk also. So if anything is happening on Sunsynk firmware updates, it's already done on Deye.

On 2025/04/08 at 8:59 AM, GreenFields said:

Respectfully disagree on one or two points, open to correction.

As was pointed out, Sunsynk and Deye have the same hardware and functions, so the improved software is not necessarily indicative of greater savings.

Also, why would a greater pass-through current lead to greater savings? The greater pass-through is what allows you to use more GRID POWER on your essential loads, which is great if you need it, but where is the saving?

It just sounds like "maximum savings" is a catch-all phrase to say why bigger is better, without analysing the user's needs and situation.

What can you run on a 5 kW inverter?

5 kW is around 22 Amps, so basically one plug circuit or a geyser and some lights

Also your solar is limit is smaller than the 8 kW unit

If I remember correctly, the 5 kW unit has a 32 Amp pass through, so basically one and a half plug circuits

Now during loadshedding or a power cut, you won't be able to have everything, or most loads available to use

With a 8 kW unit with 50 Amp pass through, you can have almost the entire house (medium size house) on essential load, except stove and geyser and possibly pool pump, but I quite often have pool pump on essential load as it often has shared essentials on the same sub DB

You may have to be careful what you use at the same time while Eskom is off, but you can have it all connected

So I can run normally the whole house plus feed back to geyser, pool pump and stove while Eskom is on under ideal conditions

You will have great difficulties doing that with a 5 kW unit, simply too small

Also here in Cape Town, you want to maximize your solar panels to get the most savings during winter

5 kW is more limited than 8 kW again.

3 hours ago, James 1 said:

What can you run on a 5 kW inverter?

5 kW is around 22 Amps, so basically one plug circuit or a geyser and some lights

Well it depends. I have a 4.6 kW inverter (short bursts to 6.9 when there's grid) and on a sunny day, with a little bit of managment we can run the whole house off of that.

Qualifiers: Airpump for water heating - on a time switch which limits it to runs a day. And full gas for cooking. All lighting is LED.

So it depends on circumstances, and what the household MUST have and what they can sacrifice. Because the heat pump is so efficient and draws less than a geyser element I can run that on the backed up side of the inverter. So all the way through stage 6 we had hot water.

I do have to impose a rule in the kitchen though: Only two appliances may be on at a time. So, for EG, you look around and see the dishwasher and the microwave are running then sorry, you can't use the kettle. Wait until one of the others is finished.

This really is not much of a problem for us most of the time. In the evening we might use the air fryer or the microwave and will definitely use the kettle. At night we have 250 to 400 W at any given time, until 6:00 when the heat pump switches on again.

I agree with your general point, but it does depend on what you can live with and without and on the habits of the people in the household. If I had an 8kW inverter I wouldn't have to impose that rule in the kitchen.

But as an example... during the day we can run fridges, lights if necessary, security, wi-fi, dishwasher, the washing machine (on a cold cycle), three lap top computers, a TV, and charge our phones. So you can do a bit more. Especially if you have fairly new appliances which draw less when they start up.

I would like 8kW though. Then I would just carry on pretty much as we do, but put EVERYTHING on the backed up side. The pool pump, the whole tooty.

On 2025/04/08 at 8:59 AM, GreenFields said:

As was pointed out, Sunsynk and Deye have the same hardware and functions, so the improved software is not necessarily indicative of greater savings.

Yeah, I've spent time with hardware from both Deye (colleagues) and Sunsynk (my own) and functionality is the same on-inverter, the only difference is terminology in the menus. And colour scheme! 🙂

My installer mentioned he preferred the Sunsynk app to the Deye solution when he did the second-half of my installation last year; especially with regards to modifying settings from the SS app. Maybe this has changed since, though. Sunsynk also has a nice API which is quite clean and well documented.

But indeed, if none of that matters (or you're going Home Assistant or the like) I'd just go for whatever is cheaper at the time.

6 hours ago, James 1 said:

What can you run on a 5 kW inverter?

5 kW is around 22 Amps, so basically one plug circuit or a geyser and some lights

It's not that bad: like Bobster mentioned, 5kW goes further than you think as long as you keep cooking and heating under control.

Our household ran 5kW for about a year before adding a second unit in parallel; and we had no idea when there was load shedding unless we needed the stove/oven. And while 5kW limited what high-power items could be done on the UPS side, there's of course no limit on what you do grid-side (ie, on the non-backed-up side) - so if you keep your loads under control, you can still zero-export-to-CT to your non-essentials; since both the Sunsynk and Deye models discussed here can zero-export to the grid port.

So even though my geysers weren't on the UPS side, they still got mostly heated from PV when sunshine was available. And when loads exceeded 5kW, the balance just came from grid. So the cost savings were impressive - very impressive - from just the one 5kW unit, mainly thanks to zero-export-to-CT. And load shedding was a non-issue.

I might've considered moving the smaller geyser onto the UPS side (with a heating element downgrade to 2kW) if I'd stuck with a single inverter. But in the end we doubled the solar-panel-count and and needed the MPPTs of a second inverter. And with the second unit, all our high-power items could go onto the inverter's Aux port since the backed-up load maximum was now 10kW.

On 2025/04/09 at 12:39 PM, James 1 said:

What can you run on a 5 kW inverter?

5 kW is around 22 Amps, so basically one plug circuit or a geyser and some lights

Also your solar is limit is smaller than the 8 kW unit

If I remember correctly, the 5 kW unit has a 32 Amp pass through, so basically one and a half plug circuits

Now during loadshedding or a power cut, you won't be able to have everything, or most loads available to use

With a 8 kW unit with 50 Amp pass through, you can have almost the entire house (medium size house) on essential load, except stove and geyser and possibly pool pump, but I quite often have pool pump on essential load as it often has shared essentials on the same sub DB

You may have to be careful what you use at the same time while Eskom is off, but you can have it all connected

So I can run normally the whole house plus feed back to geyser, pool pump and stove while Eskom is on under ideal conditions

You will have great difficulties doing that with a 5 kW unit, simply too small

Also here in Cape Town, you want to maximize your solar panels to get the most savings during winter

5 kW is more limited than 8 kW again.

I guess you are a installer. So you tell a client that with a 5kW inverter, you basically have one plug. That is sales talk.

I run the whole house and flat from 5kW.

1 Geyser - 3200 watt

1 Geyser - 2100 watt

Pool pump - 820 watt

Microwave - 2000 watt

Kettle - 2000 watt

Airfryer - 1600 watt

Rest of the house appliances is less that 500 watt each.

So you must decide what you want to run when. The geysers doesnt run simultaneously. They also do run 24/7. They switch on and off.

If your geyser is hot, you can run your base load, the pool pump, Airfryer and kettle.

24 minutes ago, McGuywer said:

I guess you are a installer. So you tell a client that with a 5kW inverter, you basically have one plug. That is sales talk.

I run the whole house and flat from 5kW.

1 Geyser - 3200 watt

1 Geyser - 2100 watt

Pool pump - 820 watt

Microwave - 2000 watt

Kettle - 2000 watt

Airfryer - 1600 watt

Rest of the house appliances is less that 500 watt each.

So you must decide what you want to run when. The geysers doesnt run simultaneously. They also do run 24/7. They switch on and off.

If your geyser is hot, you can run your base load, the pool pump, Airfryer and kettle.

If I was very careful and with some planning I could probably run the whole house from a 3 kW unit

But that would generally be very inconvenient. Having to carefully watch what is on at the same time

And if doing it for myself I could probably get away with a 5 kW unit with some less hassle

But my clients generally want a "plug and play" solution. They don't want to have to watch what they switch on at the same time

With the exception of the geyser that we generally put on a smart timer, they just want to live life as before and get the savings on electricity

I would be quite interested to see on your installation how much the grid has to fill in during a week? I would definitely suspect a lot more than if you had a 8 kW unit. If you look at the total cost of the installation, the difference between installing a 8 kW unit and a 5 kW unit is the same labour wise and the cost difference of the 5 and 8 kW units are quite small on the total job

I have minimal markup on my materials so doesn't make any difference to me which one they choose. But I have built up a good reputation for supplying the right product to the client with maximum savings.

@James1 , agree with you there, I am also an installer and run my own house on a 5 kW, wife has learnt how to keep grid to essentially zero ( trickle feed ) and except for geyser and oven on non essential, whole house is on essential, hardly an ac overload trip, but, yes, for clients, who don't to to bother managing loads, i try to steer them away from the 5 kW, if at all possible. My markup and labor is the same for a 5kw or 8 kw, so only difference is price of the 2