Fronius Primo GEN24 Plus Hybrid Inverter – Backup Without A Battery

Fronius Primo GEN24 Plus single phase hybrid inverter

Fronius has announced its GEN24 Plus hybrid inverter is now available in a Primo single-phase variant – and it can supply backup power without a battery.

A hybrid inverter has the ability to manage the electricity output of solar panels and charging a battery system while also operating with mains grid supply.

The Primo GEN24 Plus is Fronius’s first single-phase hybrid inverter, following in the footsteps of the 3-phase Symo Hybrid and more recently the Symo GEN24 Plus.

“The Primo has countless open interfaces for linking together the energy, storage, mobility, heating and cooling sectors,” said Martin Hackl, Global Director of the Business Unit Solar Energy at Fronius International. “We’ve packed it full of future-proof technology to make it possible to get the most out of the photovoltaic system over the decades.”

Primo GEN24 Plus Basic Specifications

  • Capacities available: 3 – 6kW
  • MPP Trackers (MPPT): 2
  • Efficiency: 97.6%
  • Weight: 15.4 / 19 kg
  • Dimensions: 530 x 474 x 165 mm
  • Noise: < 42 dB (A)

You can find other specifications of the Fronius Primo GEN24 Plus and see it how it compares against other inverters on the SolarQuotes hybrid inverter comparison table.

Backup Without A Battery – PV Point

One of the very interesting features of the Primo GEN24 Plus is its ability to continue supplying electricity to a home in the event of a mains grid disruption, and without a battery.

The PV Point feature, which involves installing a dedicated power point beside the inverter or within the home, can provide a maximum of 3,000W during a blackout situation.

While it means plugging in loads in such a situation and will only be useful when the sun is shining – and there is a 60-90 second changeover time – it makes the Primo GEN24 Plus an even more compelling option for solar power systems buyers and owners wanting a backup solution but who aren’t ready to purchase a home battery.

Full Backup, But..

Where a battery is present, the GEN24 Plus Primo enables power currently being generated to be consumed and for surplus energy to be stored in the battery – but it will need to be a BYD B-Box battery.

Active Cooling

Most solar inverters these days – hybrid or otherwise – use passive (aka “natural” or convection) cooling, but Fronius uses active cooling; meaning a large fan. While providing superior cooling performance that helps to extend the working life of an inverter, it also creates more noise.

At < 42 dB (A), the Primo GEN24 Plus would be louder than a Delta E5 , which also offers backup power functionality without a battery. But louder doesn’t mean really loud. 42 dB is a bit more than the level of a computer fan, but it may still be a consideration in terms of inverter placement.

Fronius has been producing inverters since the 1990’s and its solar products are considered among the best in the world. Fronius solar inverter reviews here on SolarQuotes have generally been very positive and there has been a lot of them; more than 4,800 ratings and reviews at the time of publishing.

On a related note, Fronius says the three-phase Symo GEN24 Plus will be also be available in the smaller 3, 4 and 5 kW power categories next month.

About Michael Bloch

Michael caught the solar power bug after purchasing components to cobble together a small off-grid PV system in 2008. He's been reporting on Australian and international solar energy news ever since.


  1. Bret Busby in Western Australia says

    “The Primo has countless open interfaces for linking together the energy, storage, mobility, heating and cooling sectors,” said Martin Hackl, Global Director of the Business Unit Solar Energy at Fronius International.

    So, does the interface for “mobility”, mean that this inverter model can both charge and draw from, the battery in a BEV?

    What inverter models in Australia, have that functionality?

    • Phillip Wheatley says

      One good reason I would buy a battery is to provide power during a grid outage. I note a comment in your article on the new Gen24 plus hybrid that this model follows in the footsteps of the Fronius Symo 3 phase.. I presume you are saying that the 3 phase model will provide power to the home during a blackout. Is this correct? I installed a 3 phase Fronius Symo 8.2 inverter ( to power my 3 phase A/C.

  2. Des Scahill says

    I suspect that this device is something that many of those who don’t want to purchase a battery at this point in time will welcome, even if only as a kind of ‘insurance policy’. over the next 5 – 7 years.(or even 10?)

    It’s extremely frustrating as a solar PV system owner to find yourself completely without power as a result of a grid failure, shutdown, or simply excessive demand in some other distant large metropolitan area that causes rolling shut-downs in areas with far lower populations..

    Between now and at least 2026 (the optimistic roll-date for Snowy 2.0), it seems quite likely to me that we will have:
    – more frequent extreme weather events
    – increased demand (esp air con) because of higher temperatures for longer periods of time.
    – rising household, small and large business demand for EV’s of all types

    Even just those few items all point towards an increasing likelihood of grid shut-downs in the relatively near future.

    I don’t believe the existing overall transmission grid problems are all going to be fixed any time soon either.

    Now, 3 kw output isn’t much but it enables such things as:
    – some types of internet based home-businesses will be able to at least partially operate, rather than be shut down completely.
    – you’ll be able to at least run a few fans to help with cooling, and boil
    some water.
    – use your TV to keep abreast of news etc.
    – keep a fridge or freezer going
    – use a microwave for cooking
    – recharge mobile phones, small laptops, night-time lamps etc

    Except for maybe the odd high-consumption item such as electric kettles, you’ll probably be able to do more than one of the above activities simultaneously for reasonable amounts of time during daylight hours. .

    You might need to turn your hot-water system off too, depending on its size and wattage

    Overall, depending on what the cost will be, the device could perhaps be seen by many as another helpful step towards increased ‘self-sufficiency’.

    Sure, somewhere around 10-15 kwh total daily output isn’t exactly going to meet all your desires, but its a heck of lot better than nothing at all.

    • Des, the backup power from the inverter isn’t supplied to the home’s regular circuits. All regular circuits are dead during an outage.

      In backup mode the inverter only makes power available to one specially designated power outlet/circuit. You’ll need to plug whatever you want/need to power into that single outlet.

      You could of course get a sparky to wire up a power inlet connected to your home’s regular circuits via a cutover switch in the same way you might provide power backup via a generator, and instead of a generator you use the inverter’s output. Usually when you do this you exclude high power circuits from being supplied on the backup side of the cutover switch.

      The problem with such a system is the power supply is prone to great variability and may not be able to supply the demand. One cloud comes over and you may well be SOL. And of course in low light/night there’s no power anyway.

      People need to consider what typically causes power outages where they are. If it’s typically due to transmission problems because of storms, solar PV output is going to be compromised anyway.

      If you want/need backup during outages I strongly suggest not considering this inverter alone as providing a workable solution.

      • Jim Gleeson says

        Does that single point function also apply to the Delta 5?

        • Finn Peacock says

          No, the Delta E5 keeps its AC output running as long as there is enough sun.

          • Jim Gleeson says

            Thanks Finn.

            So then, running the general house power as best it can with the grid power down.

            My priority is to be able to deal with a repeat of previous summer’s extended bushfire smoke with hot days ie running air cons.

            Also, any articles etc on calculation of the hours a battery eg Powerwall 2 can run RCAC heating at night?

      • Thanks for the review and response to queries Alex. If one installed the circuitry to allow the plugging of a generator directly into the home’s power supply, could not the Gen24’s PV back up be plugged from its dedicated GPO to the generator connection?

  3. Thanks for the article. I’m trying to consolidate which inverters are currently available that provide back up power when the grid goes down, without a battery. I think it is a great feature and with it I wouldn’t bother getting a battery if I could choose the right inverter. So far I have learned the following do:
    1. This 5kw fronius gen 24 plus.
    2. The delta 5 kw (mentioned in a related article on this site).
    3. It seems some models of the hauwei can when fitted with a “back up box”, but the information on the hauwei site is very vague.
    4. SMA sunnyboy, has a model with a 2 kW limited backup output.
    I’m interested to know if there is more or if I have bad info. It would be a good article for someone to write up… please?

    • Des Scahill says

      Hi Sean,

      I agree with you that an inverter with this feature goes a long way towards avoiding the need for an expensive battery, especially for 1 or 2 person households., or those running an internet based home business of some kind.

      There might be a problem though – most households have single phase power and some of the inverters with this feature might require 3 phase powe

      There might also be a further potential problem in finding an installer who fully knows what he’s doing with the particular inverter brand and model thereof that you purchase, because the technology changes quite quickly

  4. Hank Doll says

    I can’t find an answer on one of the questions I had using the combination of Fronius Primo Gen24 with a BYD HSV where the maximum BYD units seem to be 3 or 7.7Kw while the HSV by itself can go to 4 units and 10.2 and if my memory is correct even allows 5 battery units.
    Cheers Hank

  5. Ziyad Saeed says

    Q1: Does it still have the 60-90s change over with battery as well. That means it cannot be used as a UPS.
    Q2. It other fronius backup solution they mention that the backup mode can only be operated 15% of the time. Does this limit exist in the gen24 as well.

  6. I got one of these installed about 2 months ago am I install is still trying to work out how to get the backup power option working. He’s talking about putting in a switch so I have to come out and manually change it over but you’re saying in his article it should automatically do it 90 seconds. Does this device require a fronius Smart metre for to do that? I do not have one of those and he has not told me that I should so I’m trying to do a little bit of research myself can you help me?

  7. Hi- has anyone at SolarQuotes had a chance to look closer at the Fronius gen-24 inverters. They aren’t in the hybrid inverter table yet and I wonder about some of their specs and options given the difficulties Tom had recently in your recent video.

  8. I love my Gen24 with Plus license.

    PV point has been great a couple of times now {Planned service outage and Storm unplanned outage}. If you get creative, you can get good benefit out of this 3kW PV Point capability.

    Have your electrician install a changeover switch on your nominated critical power point circuit. This is done in the switchboard, and involves switching the e.g Kitchen circuit from MAINS SUPPLY to PV POINT and back again after an outage. [There is also a full backup operation mode which requires more design / thought]

    While it is a manual flick the Change Over switch process, it can allow you access to keep using the roller door / fridge / microwave / network cabinet and plug in lamps during daylight hours.

    I’m about to add a battery, so it should allow me to ride through cloudy days as they impact your solar production which can trip you off if you if you are consuming less than 3 kW but more than what the panels are producing at a moment in time. The great thing about Fronius is the 1.5 times over subscription of panel to inverter ratings. Meaning that a 5 kW inverter can have 7.5 kW of panels feeding it, which should normally guarantee some output from PV Point as clouds pass over.

    Well done Fronius on some creative thinking!


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