Help me choose: Sunsynk vs Growatt

I’ve been threatening to install some solar at our place for the last year and am finally ready to pull the trigger. Now the big question that remains - what inverter? For context, my main aim is to bring down the monthly bill (loadshedding fortunately isn’t an issue) but since I don’t have a spinning meter I figure I need to go hybrid. We currently use about 25kWh / day, and I’m guessing this will increase as the kids grow older.

Inverter wise I’m torn between an 8kW Sunsynk or 2 x 5kW Growatt’s. 2 x 5kW Sunsynks are just a bridge too far ito costing. It’s important to me that the inverter be able to use all the available solar, add battery when more power is needed and only use grid when solar and battery combined are insufficient. I’ve decided on Pylontech batteries, so being able to limit discharge current from the inverter will be a big plus, as is reasonably seamless Home Assistant integration. I’m not an expert on either, so could be very wrong, but at the moment I have it as follows:

Sunsynk 8kW

  • Pros:
    • Good local support (official and from community).
    • 50A AC passthrough
    • Multiple MPPTs
    • Blends solar and battery
    • Can set max battery discharge rate
    • 5 year warranty
  • Cons:
    • Fan noise
    • More expensive of the two options (about R10k more)
    • Home Assistant integration is cumbersome

2 x Growatt 8kW

  • Pros:
    • Cheaper option
    • Home Assistant integration
  • Cons:
    • Low MPPT voltage
    • Noisy
    • 2 year warranty
  • Unsure:
    • What happens when rated current is exceeded / is there AC pass through?
    • Can it blend solar and battery?
    • Can battery discharge limit be set?

Your comments and inputs would be much appreciated

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Welcome to the forum!
I can’t comment on the inverters but the standard installation is grid tie. This means that the inverter remains in sync with the mains and draws power when required. The difficulties with this model is that the utilities (throughout SA!) have virtually prevented you legally feeding back into the grid.
So the inverter needs to be able to be configured to only draw from the grid.
The current hybrid inverters are very flexible but it’s best to do your homework.
Search the local forums (except for Powerforum) for the users who have the inverter you are sold on. Ask them specific questions you need answers on…

i installed a 5 kW Sunsynk as a grid tied ( no battery ) as client also is not worried about load shedding. Just need to install the supplied CT clamp as close as possible to the grid meter, and it works !!!

Sunsynk. Start with one if budget is a constraint.

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I don’t know either of the 2 very well, however with these type of systems the most important thing for me will be warranty as well as local support rather than purely looking at price.

Take Tesla as an example, they make awesome vehicles but at this stage I won’t touch one with a barge pole since they have zero support and backup in SA.

If you are going grid-tie, check regulations. Some inverters might not be approved by your local municipality to use in grid-tie setups.

My two cents: I use a Victron and integration with Home Assistant was incredibly easy (and I had zero experience with it before). Can access a lot of info as well as modify the inverter’s settings on the fly using Modbus. I’ve not seen how the Growatt (there’s many models, not sure which one your are referring to) and Sunsynk integrates with HA.

Also ask the question: Can the Growatt feed non-essentials?
The SunSynk is NRS tested and approved for installation in places like Cape Town. (Okay I note the Growatt SPH series is also listed, so that is a good thing).

I have heard a few horror stories on the longevity of Growatt inverters, but I think this is more referring to the SPF range, which I would never recommend. This would be classed as an off-grid inverter and you end up being very disappointed by the overall system performance.

With SunSynk or Victron or any other bi-directional, hybrid inverter you will be able to feed the non-essentials when the battery is full and the PV is more than the backup load. (To be honest, the inverter does not see a difference between the backup load and the non-essential loads). This results in massive savings.

Avoid the cheap ones without getting a very good reference and overall statistics.

I don’t think there are any regulatory issues with either product in Tshwane. Also, it won’t be strictly grid-tie as I’ll be able to run in the case of power failure too.

Victron isn’t an option.

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I don’t need to be able to feed non-essentials, everything will run off of the inverter.


Well, at least not without some significant crowdfunding.

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Just make sure to check out any applicable regs. In CoCT they do not care if you also use it while there’s loadshedding.

Thanks for the headsup. Just a quick question - it’s the second time you’ve posted about the regs. Is there anything specific you think I’m missing?

You didn’t give the specific details of the Growatt inverter. Some of them are what I consider to be “off grid”, some seems to be the same as a Goodwe. I’m sure there are many more.

While I’m aware of the few Sunsynk models in SA and pretty sure they are all at least on CoCT’s approved inverter list, I don’t know about the Growatt inverters. Also, you aren’t in CoCT so perhaps looking at the JHB list is safer, and I have no knowledge of what inverters are on their list. Presumably it would be the same as CoCT.

If it is not NRS 097-2-1: 2017 certified, you cannot get a CoC with it connected to the grid in any way (you would have to be completely islanded/off-grid). (Although most people that issue CoCs don’t know this…)

It’s the Growatt SPF 5000ES which is widely available in SA. I’d be surprised if such a popular inverter has regulatory issues.

I’m in Pretoria which, you might be surprised to learn, is a completely different city to Johannesburg. Oh, and we don’t have a “list”. That’s a CoCT thing.

Ok, back on topic: I have seen the insides of both - I would not recommend the Growatt for a permanent installation. The Sunsynk seem to have borrowed a lot from Goodwe, which is a very well-thought-out design, but the Sunsynk also runs much hotter, which will affect life-span. (although I do not expect it to become an issue in the warranty period)

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And there I read it again … it is not a CoCT “thing”.

The fact is that CoCT just made the effort to list all the NRS certified inverters.

Take cognizance of the fact that Tswane is now closer under full DA “control”. Also, take note of how they went about collecting arrears recently.

Why does it matter? They may start enforcing the South African NATIONAL SANS/NRS regulations there too, which again is not a CoCT/DA thing, but a SA national regulatory “thing”. :wink:

See, we in CoCT have “walked the talk” the last few YEARS, we’ve got the “scars” and the “T-Shirts”. These NRS /SANS regulations in and around solar grid tying is worth it, let me tell you. If Tswane has no regulations in place yet, use CoCT one as a guide. There could be small differences in the end once Tswane starts enforcing, but the core fact is it is still national SA regulations.

Get an NRS certified inverter. It can “future proof” your installation.

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I’d still steer clear of the Growatt, just because I had one (not the particular one you are looking at) and documentation etc. around it was horrible. This was a few years ago, maybe they’ve upped their game.

I know that JHB is a different municipality (and city), but it was purely used as an example. They didn’t have any regulations around inverters until the DA took power at the municipal level. Then they got a “list”, pretty much the same as the CoCT one. Technically they always had regulations around solar but it wasn’t enforced (or something like that).

All I’m doing is letting you know that there are regulations to comply with, parts wise as well as installation wise, and for it to “work” isn’t necessarily legal. When I was getting ready to install my solar system, I contacted an installer who did a great job, but the system would not have complied - I just assumed that the installers understand the regulations.

If you only have bad options on the table, I’d go with the Sunsynk.


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