I have 10kW SAJ solar inverter for 9 years that just died (not completely but it wont synchronize to grid anymore). Because the support for SAJ inverters is very bad and the installer went bankrupt, I cant make use of the 10y warranty and this means I need to buy a new one.
So, I am looking for recommendations from the community on their experiences with different inverters. I might go for a hybrid now (but I don’t have battery yet, I have started evaluating the need for it this year, since until recently I had a Ferraris meter that just rotated backwards when there was production)
I know this topic, but it is only related to the models that work with OH.
I want to hear the good and bad experiences.
Of course, it needs to be able to work with OH, without the need for a cloud connection (I plan to block the traffic to internet via my firewall)
I have a Fronius Symo Gen24 Plus hybrid inverter (10 kW AC, up-to 15 kWp DC) running for nearly two years now and it’s doing a great job. Fronius Solar API is well documented and works fully local (you have to enable it in the inverter settings) and I have implemented battery control in the Fronius binding based on what the inverter web UI does.
You can configure it fully through its local web UI, at some point in time remote-configuration support has been added to Solar.Web, but this is disabled by default. I allow it to send it’s production data to Solar.Web, but given that openHAB communicates fully local, you can block internet access for it.
You will want to have an all-local, simple to control but as-flexible-as-possible inverter that is also good at controlling battery charging, and probably a big, well-reputated brand this time.
I’m operating quite some different models with my (commercial) HEMS so I can compare and I would recommend in that order one of Sungrow, Kostal, Fronius.
I’d rather stay away from SolarEdge, SMA, SENEC, Huawei, Deye and any of the low cost Chinese brands that you cannot be sure will still exist in two or three years.
Sungrow I’m using myself since some years, they’re #2 worldwide I believe, and they even have models with UPS capabilities builtin for a small premium.
Just a note wrt UPS capability: In my experience (know a Sungrow owner), their backup power supply switches on so fast that the inverter feels like a UPS for normal electronics, but keep in mind that computers still need a real UPS.
Also, depending on your electrical installation, you cannot to the backup power switching in the inverter but need to to it externally (e.g. if you cannot wire this up due to the inverter being in a different location than you main electrical installation), then you need an inverter that does this externally, like Fronius.
Well, the advantage of those Sungrows is that they can run off-grid without a need to restart first and that it’s a builtin capability. With Fronius, Kostal, SolarEdge or others, I think they all need to reboot or resync for several seconds.
And what’s worse, you MUST switch externally, and it is always expensive to set that up.
The UPS part actually is just sort of a goodie. Actually more often than a grid failure the reason for an outage is on the inside like a short circuit or triggered RCD in your home, and that the inverter cannot cover.
I wouldn’t run a data center off it either, but for a PC and router there’s a fair chance they keep running and hey, the feature is there for free, so why not.
For me, the #1 advantage of a Sungrow is that it is so uncomplicated to use all those advanced features like forced battery discharging that most vendors intentionally hide behind admin level access. Which most electricians still refuse to pass on to users. I really hate that paternalism.
Soooo German.
Well hard to explain to someone that hasn’t experienced it himself.
As a HEMS vendor willing to remote control the inverter, it was giving me a hard time. The inverter “felt” sort of oppositional. And documentation is a bad mess. A lot of its behavior depends on the exact model and setup. I had to do a lot of trial-and-error.
It’s probably working if you use the all-SMA ecosystem and their SHM (SMA’s own energy manager) but it was really stressful to figure out how to generically control SMAs.
Not really an open system. Not fun if you intend to implement your own (openHAB) control layer.
My Fronius doesn’t need to reboot, just a few seconds to disconnect the grid and double-check that.
Having this externally can be a major benefit as already said. If the inverter cannot be close to the main cabinet, you cannot pass your house through it and you then need to do the switching externally. Inverter in garage, switching technology in main cabinet at the other end of the building.
At the time we bought our inverter, also Sungrow SH10T could not pass through more than 32A or something like that, when switching externally, we don’t have that limit.
TL:DR; IMO you cannot generally see externally switching as a drawback, depending on the installation, it might be required or beneficial.
We never had power outage in the full building due to short circuit or RCD, but grid outages happen several times a year – our grid operator did not maintain the grid well or at all.
That was also my impression when I looked into SMA two years ago.
Yeah, what I rather meant is that you will be having an interruption of power, so non-UPSed devices like routers and computers will restart.
Depending on what’s your local environment and requirements, it might be required, that’s true.
But external is not really beneficial unless you compare apples to oranges that cost a lot more than the apples do.
Sure, a Sungrow has limitations like a maximum power per phase it can only provide in grid online mode too, but you get a fair set of capabilities essentially for free.
External switching on the other hand you can set up with many vendors, but not every electrician is able and willing to. And for sure it is always an expensive and complicated thing to do.
However I believe we’re getting off topic here, I think the OP didn’t ask for that level of resilience.
Actually I dont see the external action as a drawback. If the power is off you might want to switch off the unimportant loads and keep the ones that matter.
Also I am curious how you prevent feeding the complete neighbourhood, because the main feeder breaker remains on.
I don’t know the typical UPS switching circuit of inverter works, but we usually solve similar problems by connecting a relay over 2 phases (or phase and neutral). The relay is energised as long as there is main power, but when the main power fails this relay deenergises and you could use normally closed contact to activate the off grid / UPS mode. But the problem with feeding the neighbourhood still remains unless you use some contractors to switch off the unwanted loads
Again apples to oranges. The drawback is the cost.
I have actually only put important loads behind my Sungrow’s protected output.
Unimportant ones (like washing machine and dish washer) and I-don’t-want-to-be-protected-loads like my heat pump and ev charger are left out.
The latter ones I don’t want to drain my battery when running off grid.
Like with an external setup. Sungrow has just essentially moved the external breaker into the inverter.
Actually a funny problem of mine was quite the opposite. I had some outages with the main breaker being off unnoticed for probably weeks until it was getting autumn and the battery could no longer provide enough power to cover the full night and my home blacked out.
And I’m happy it does 3-phase. Interlinking phases like I believe SMA also offers on some of their products to me feels like paving the road to doom. But hey just my $0.02 I’m just a software guy.
Usually it is not like that. Maybe in new electrical installations you would have your essential loads behind the UPS so the UPS will disconnect the power grid relay and is not feeding the grid. However in most of the residential electrical installations the inverter is connected in parallel to the other loads, and in those cases you would need to switch off the mains breaker or open the main feeder circuit in some other way.
At the place where I live, the power outages are very rare, most of the time only when technicians are working. So preventing the inverter feeding back to the grid is must, because of safety of the people that might working down the street.
But back to the subject, I am looking into Kostal Plenticore G3 – M 8.5-12.5 kW.
I am planning to do the exchange myself, but from what I understand you need to use some PLENTICOINS to be able to activate the battery and UPS function and this can be done with installer account, which I obviously dont have.
Do I get it right? Anyone experience with this type inverter? If that’s true then it is dealbreaker for me.
Of course it is. When you have an inverter that is capable to run an island network, it is always like that.
Either you have a hybrid inverter that physically disconnects itself (more precisely: all of its power provider units, i.e. battery and PV strings) from the outside whenever it detects a grid outage.
Or it controls some external unit to hit the breakers on its behalf.
Beware that if there’s additional power sources like more inverters that are parallel to the island-generating inverter you will need that because those cannot determine where the grid clock comes from so they don’t know they have to shut down.
My point is that normal house doesn’t have the split, you have to specifically regroup your essential loads to be fed from the UPS.
On the other hand, failure of the UPS will leave your essential loads powerless. I personally would avoid powering the essential loads constantly through the inverter for a simple reason that the inverter has more components that can and will fail. I would rather keep it simple and maybe wire a power strip that I would use in case of need of a backup power.
From what I can see, Fronius has power socket already available, or as other option it can feed the complete house but then you need to install switch that will disconnect it from the power. Fronius offers a manual switch from what I can see.
Will dig in the technical specs of those two invertors in the next few days.
Sungrow is 1/2 the price from what I can see but need to check if it offers all I want.
I would most likely not go for an option to install the main switches, since it will require that independent inspector to test and accept the modification, and I will try to avoid that.
Yes but if you do all of this for resilience reasons you should be doing that anyway. As I wrote you won’t want your heat pump or any non essential large consumer to run when you’re off grid.
My suggestion is victron, it can build a offgrid within 20ms. You are able to control the system by yourself and due to venusOS and Node-Red you have the possibility to implement it into OH, HA or whatever.
I have a 3 phase Solis HV hybrid inverter, coupled with 12kW of panels and 68kWh of storage (using Battery Emulator).
I use OH to automate both the inverter and the battery controller. The inverter has all registers available via modbus, or you can use the Cloud web interface. It will operate disconnected from the grid, has a backup port rated atv10kW total.
one additional:
I’m totally happy with my Goodwe GW15K-ET.
All registers that are relevant to me can be read and written via modbus binding.
It took me a little to find some registers (e.g. forced charging) in the newsgroups but works very reliable.
I never tested the off-grid functionality (as we never had a power outage).
I can recommend Fenecon. It is a german company behind openems, which is used on their systems. I have a Fenecon Home 10 with 20kw panels and 50kw Storage. It is running latest version of openems.The inverter is relabled from Goodwe, but it is running their own software. The storage is build inhouse.
I can control it via modbus or rest. I implemented 4 use cases.
Charge with cheapest energy during winter time, to have enough for the next day (including heating). This happens only if not enough solar energy is expected. So mostly between October/November until February).
Prevent discharge, if no charged solar energy is available and the leftover charged energy (charged from grid) has a avg price more the the current stock price.
Limit charge energy during sunshine to distribute the charging across the day. The logging includes solar forecast and calculates full charge until 80% of the expected solar charge happens. This guarantees that, even if the forecast wasn’t entirely accurate, the remaining 20% of expected solar energy will fully charge the battery. But it is mostly ~14:00 - 15:00
Stop storage charging at xx%, if the expected solar energy on the next day is “more” then enough and the current battery level is “more” then enough for the upcoming night. This is good for battery life. Currently, it stops between 75% and 88%. And every 7 days, it fully charges until 100%, because the storage technology (LiFePO4) needs a re calibration in fixed intervals.
