Fronius residential solar inverter review - Updated October 2024

Fronius are the 12th largest solar inverter manufacturer in the World.
All Fronius inverters are designed and manufactured in Europe.
I believe Fronius are the second most popular inverter brand in Australia.

Summary
You would probably think that someone in my job, a solar service manager, would love Fronius.
European made quality, rock solid reliability, makes my job much easier. Right?

Sort of

It's true that they rarely fail and when they do, Fronius support and warranty service is great.
What I don't like are customer complaints, and I get a few about Fronius.
That's why I direct everyone looking to buy a Fronius inverter from us to this page.

The difference between Fronius GEN24 and GEN24Plus
Plus means it can connect a battery (BYD usually).
You can buy a GEN24, then later purchase an unlock code (about $1,000) and turn it into a Plus.
I have encountered many people who bought their GEN24 thinking they were getting a battery ready hybrid.
Not our customers I hasten to add because we always tell them what they are getting.

What is dual flow and why is Fronius not very good at it?
If you buy, for example, a 10kW GEN24Plus and a BYD battery, Fronius will allow you to have 15kW of solar panels.
That's not a lot more than the usual 13.32kW you can have without a battery, but every little helps.
On a good solar day, you might expect 10kW of AC power flowing to your home and a further 5kW to charge the battery.
That's what dual flow means.
The problem with Fronius is that they can't do it very well.
The total AC + DC capability of the 10kW Fronius is 10.3kW even if you have 15kW of panels.

The same applies to all their other GEN24Plus models. You only get a fraction over the AC rating.

If you bought a Sigenergy, iStore, or Sungrow inverter instead you would not face this restriction,
and you would also be able to connect a lot more solar panels (oversizing to 200% isn't uncommon).

Not bad reporting, but not great either.
I've have had several Fronius customers expressing their disappointment with the reporting app.
There's a free and paid version but really not too much extra is in the paid version.
Personally, I find the Solarweb app adequate and I think most clients do too.
But if you are a deep diving type of individual then you may be disappointed.

Overly secure
It's a solar inverter Fronius... not a bank account.
Layers of password protection with many features locked out to remote access.
Drives me nuts. I have to drive to a customer site to change some of the settings.
Huge Tip ! Make sure that YOU decide on installation day what YOUR inverter passwords will be.
That includes the Technician password, not just the Customer password.
Then write them onto a label, take a photo as well, and stick the label to the inverter !!
Recovering forgotten passwords with Fronius is mind-bogglingly complex.

GEN24Plus plays nicely with BYD batteries.
BYD batteries were well known in the solar industry long before BYD moved into EV production.
"Build Your Dreams", always seemed corny to me, but hasn't stopped them being very successful.
The HVM model series connected batteries are 2.76kWh and a 22kWh stack of 8 reaches 2.11m high.
That's not far off ceiling height in some garages.

There are much better batteries around these days than these BYDs.
Sigenergy and iStore both have parallel-connected, optimised batteries with fire extinguishers inside.
I suspect there's a new BYD battery with more features and larger storage coming soon.
However, no denying that the BYD HVM is a quality product.

Fronius are expensive compared to what?
Growatt? Yes a lot more expensive than some brands at the 'price sensitive' end of the spectrum.
Not so much more when compared to quality rivals.

The Fronius range of inverters.
They fill every niche except one.
The largest GEN24/GEN24Plus is only 10kW.
We can go to 15kW on three phase in WA and many people want that.
You can, of course, connect a 5kW and a 10kW together. Works fine.
It's just not a very economical way to do it when others brands have 15kW models.

Universally loved by sales people.
Without doubt the easiest sell of their day for anyone seeking 'quality'.
Fronius rarely needs an introduction.
They fly off the shelves.

Universally loved by installers.
Every solar installer knows Fronius.
Most installers prefer to stick with what they know.
Learning new brands requires reading manuals, watching videos and doing accreditation courses.

Almost universally loved by customers.
Yes, I have mentioned a few things that aren't ideal about Fronius inverters.
But if you are ok with those things then this is a very popular brand.

First class support from Fronius.
Customers aren't meant to contact Fronius direct, it's people like me that they want calling them.
I find their support to be exceptionally good. The best except for iStore.
If you want to talk to Fronius themselves they will try and direct you to your solar company,
but if you haven't got the answers you wanted from them, then they will talk and help you.
Their Australian support phone number re-directs to Austria when the local Australian team has gone home.

My favourite WIFI setup
Helping people with WIFI is almost half my job.
Modems/Routers/Passwords get changed often.
With Fronius you push the WPS button on your home router/modem.
Double tap the centre button of the Fronius GEN24/Plus inverter. Done.
No other inverter I've worked with is as easy as that.

Backup when you have a battery.
Having power to your home when the grid fails is one of the best features of having a battery.
Fronius have a separate backup box, which is my preferred method rather than having it built-in.

There's a fairly slow switch-over which isn't entirely a bad thing in my view.
With Sigenergy and their UPS, instant switch-over you don't know you are in a blackout.
The lights don't even flicker.
Good on one level, but bad on another.
You might want to turn a few unessentials off if you knew you were in a blackout to conserve your battery.
With Fronius taking many seconds to switch, you know for sure you are in a blackout.

Backup power when you don't have a battery.
PV Point is a uniquely Fronius feature although I'm pretty sure SMA used to have it many years ago.
We wire up an RCD protected outlet, usually next to the inverter.
When the grid fails you plug an extension cord into the outlet and run things from that.
No battery required, it runs entirely from your available solar power.
Max 3kW (approx 15A) as long as the sun is shining.
It's an optional extra installation cost, but nothing to pay as far as Fronius are concerned.
You can see it in the picture below.

Fronius WattPilot
Fronius have smart EV Chargers called WattPilot.
Note:Photoshopped next to each other, WattPilot is too large.





The version pictured is portable (WattPilot Go), and the same price, about $2,000, as the fixed version.
You also need to purchase an EV charging cable, 32A Type 2, currently around $360.
We wired up a three phase outlet in this customer's garage, but they can unplug it and take it with him.
It has a single phase adaptor cable so it can operate on any normal power outlet.
It can charge at 10A, 16A, 22A, 24A or 32A

What is particularly good about Fronius WattPilot is how it communicates and interacts with the Fronius GEN24Plus inverter.
If solar production is weak then it can automatically reduce the charge rate, ensuring you don't pay for grid power.
If the GEN24Plus has a battery then there are settings to allow charging times and priorities between EV and solar battery.
You can set a percentage, say 20%, that the battery can be charged to before EV charging commences.

Performance with panel shade and multiple roof orientations.
As with pretty much all the good inverters these days, the Fronius inverters performs regular MPPT scans.
Fronius call it 'Dynamic Peak Manager'
This really helps deal with some of the more common types of shading.
Some claim the function is so good you don't need optimisers at all.
I've seen before and after results on real Perth installs where optimisers were added later (retro-fitted).
The output improved quite significantly, so I'm more in the 'use optimisers' camp, just from personal experience.

Do Solar4Ever sell and install Fronius?
Yes we do. Not as many as we used to, but we certainly still do.
I feel the playing field has leveled over the past five years in terms of quality and reliability.
Fronius were such an obvious quality choice for so long.
Now that's much more blurred.

The wheels turn very slowly over there in Austria compared to China.
The Chinese are bringing out new stuff all the time.
Inverter models are superseded every three or four years.

Fronius ran with their last range, the Snap Inverters for ten years.
I suspect Fronius hope that GEN24 will have a similar production line longevity.
It's far more profitable to keep things the same.
I think they risk being left behind and on several features, they already are.


Datasheets
Fronius Primo GEN24Plus (single phase)
Fronius Symo GEN24Plus range (three phase)