Solar + Battery Upgrade Quotes (40 Kwh with Blackout Protection)

focus123 on 15/10/2025 - 08:08

Solar + Battery Upgrade Plan (40 kWh with Blackout Protection)

I am looking to install a 40 kWh battery with blackout protection.

I currently have 6.6 kW solar panels with a 5 kW Fronius inverter.
I would like to add another 6.6 kW of solar panels and get a 10 kW hybrid inverter with DC coupling for both new and existing solar panels, and remove the existing Fronius inverter.
The property is single-phase, single-storey.

Current Usage

Winter grid import: ~20 kWh/day
Expected future winter import: ~30 kWh/day (now have an EV requiring ~10 kWh/day)
Summer: Previously in credit; minimal AC use
Future summers: Expect ~10 kWh/day for overnight EV charging

Predicted Annual Savings from Solar + Battery

Season	Duration	Daily Saving	Rate	Total
Winter	90 days	25 kWh/day	$0.45 /kWh	$1,012
Summer	90 days	5 kWh/day	$0.45 /kWh	$202
Autumn & Spring	180 days	10 kWh/day	$0.45 /kWh	$810
EV Charging	Year-round	2,400 kWh	$0.08 /kWh	$192

Approximate total annual savings: ~$2,200

Quotes Received

The first three are from established companies (10+ years in business).
The rest are from newer companies advertising on social media.
Based on these prices, the payback period ranges from ~3 to 10 years.

Quote 1

6.6 kW Aiko Energy 475 W panels
SolaX Power X1-VAST-10K (10 kW hybrid inverter)
SolaX Power T-HS40.9 [AU] (41 kWh battery)
DC coupling: new + existing panels
Blackout protection: 2 circuits (lights + power points)
Price (after rebates, incl. GST): $16,000

Quote 2

6.6 kW Jinko 510 W panels
Sigenergy SigenStor-10S-40 (10 kW hybrid inverter)
Sigenergy SigenStor-10S-40 (40.3 kWh / 39 kWh usable battery)
DC coupling: new + existing panels
Blackout protection: 2 circuits (lights + power points)
Price (after rebates, incl. GST): $22,800

Quote 3

6.6 kW Jinko 510 W panels
Alpha ESS SMILE-M5-S-INV (5 kW hybrid inverter)
Alpha ESS SMILE-M-BAT-5P VI (30 kWh usable battery)
DC coupling: new + existing panels
Blackout protection: 2 circuits (lights + power points)
Price (after rebates, incl. GST): $11,300

Quote 4

No new panels
FoxESS KH8 (8 kW hybrid inverter)
FoxESS EQ4800-L9 (42 kWh battery)
Blackout protection: 2 circuits (lights + power points)
Price (after rebates, incl. GST): $5,500
DC coupling existing panels + removal of old inverter: + $500

Quote 5

6.6 kW Risen panels
2 × Alpha ESS SMILE-M5-S-INV (two 5 kW hybrid inverters)
4 × Alpha ESS SMILE-G3-BAT-10.1P (40.4 kWh / 38.4 kWh usable)
DC coupling: new + existing panels
Blackout protection: 2 circuits (lights + power points)
Price (after rebates, incl. GST): $9,500

Quote 6

6.6 kW Seraphim panels
Fox ESS KH 10 kW (1 phase, 4 MPPT hybrid inverter)
FoxESS EQ4800-L9 (42 kWh battery)
DC coupling: new + existing panels
Blackout protection: 2 circuits (lights + power points)
Price (after rebates, incl. GST): $8,500

Quote 7

No new panels
Fox ESS H1-G2 5 kW (1 phase, 2 MPPT hybrid inverter)
FoxESS EQ4800-L9 (42 kWh battery)
DC coupling: existing panels only
Blackout protection: 2 circuits (lights + power points)
Price (after rebates, incl. GST): $6,500

Open to feedback or suggestions — particularly around DC coupling reliability, inverter selection (SolaX vs Sigenergy vs Fox ESS vs Alpha ESS), and value for money for a single-phase system.

Poll Options

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Home & Garden Solar Battery

Comments

MrThing on 15/10/2025 - 09:09

quote 2 all day long

Jinko are a rock solid panel choice and have been in the Aus market for ages
The installer you picked has also been in the market a long time - how do they rank review wise on solarquotes?, do they use their own labor to install or use a 3rd party?
Sigenstor, new kid on the block (relatively speaking) but is mega popular now and its really a neck and neck race between it and a tesla, also it provides a proper full home back up versus the tesla (sigenstor is not a ups but its change over time from mains to battery in the event of a blackout is basically (not quite zero but close), whereas the tesla you will drop power before everything powers back up again). Its just a better all round system with more functionality, more modular and a great app. Ranked number 2 on the solar quotes battery reviews and I think it outsells the tesla powerwall 3 as well.
- 7ekn00 on 15/10/2025 - 10:21
  
  Not to mention the SigEnergy has V2G, so to add more battery, just buy a resale cheap EV as battery :P
  - lgacb08 on 15/10/2025 - 20:27
    
    V2g is moot, by the time you get all the gear up, you can double battery capacity for less than the cost of a charger. Grid power is continuingly being dirt cheap by middle of the day, by the time you get your missus or whoever having the ev back you could've the battery half filled for 50c, the gear and the spare ev will never pay for itself.
    Whatever sigenergy is offering is gimmick at best.
urahara on 15/10/2025 - 09:12

+2

You're wrong in your calculations of not considering battery price drops (which will be significant regardless of the subsidy)
Having said that few other things to consider are EV plans from providers offer way cheaper charging at night/afternoon
Your best bet would be something which just keeps you afloat in mornings and evenings (until night when cheaper plan kicks in and you can top up ur battery again)
I dont see an early ROI with the kind on money you are spending when sodium ion batteries are already getting into production and most likely will be available in next 6-9 months.
- MrThing on 15/10/2025 - 11:01
  
  just getting into production, cheap, new and just estimates on when they will be widely available
  
  this just says "I will be at a premium price for a while when I am fully released to the wild"
  - urahara on 16/10/2025 - 10:11
    
    @MrThing : When I say something is ready for production what I mean by that is it has already gone through the rigorous testing cycle and production line for its mass production is ready.
- SeanConnery on 15/10/2025 - 21:56
  
  +1
  
  100% agree. Sparky friend of mine also advises not to rush with this. He estimates by June next year, the battery prices will be cheaper even without any government subsidies compared to today's prices with subsidies.
mskeggs on 15/10/2025 - 09:29

+1

I think it boils down to how you value your time and attention versus dollars.
If you spend up now, you can basically not think about it for 10 years+ in all likelihood.
If you take a cheap option you will probably need to revise in 5 years or so, but will have cheaper options by then (at least in batteries, I can't see panels and installation labour getting much lower).
netjock on 15/10/2025 - 10:16

Just get the battery then on an EV plan and charge the battery during the free / low priced windows.
- isthatallyougot on 16/10/2025 - 11:14
  
  Is there a way to just get a battery with the government rebates? I was looking at only a battery, but I was told I needed solar panels as well.
Naigrabzo on 15/10/2025 - 10:33

+1

Quote 6. You want to pay the least possible now given the ROI is slightly uncertain.
freefall101 on 15/10/2025 - 11:35

Your numbers look a bit optimistic on the winter side of things, how much are you currently producing and using? My 6.6kw averaged less than 10KWh a day in June, you're going to have to be very diligent on charging/discharging and usage to get 100% of the benefits (along with predicting the weather). You'll have days where excess goes into the grid, but a couple of rainy days in a row and you'll deplete the battery. Plus, charging the car you'll likely want to fully charge it some nights, drawing more than the battery holds.

IMO I'd look at two parts, how much a battery will reduce peak usage from the grid (which is where the benefit lies) then how much will the solar help you cover what you're not generating enough for right now. You might find the battery makes a lot of sense but the extra solar doesn't (or vice versa).
- focus123 on 15/10/2025 - 12:06
  
  My current 6.6 system with Fronius 5KW inverter has performed as follows, based on AGL import/export data
  185/575Kwh in May,
  340/410Kwh in June,
  385/310Kwh in July,
  290/525Kwh in August
  275/612Kwh in September
  97/344Kwh in 13 days of October.
  
  July has been the lowest-generating month. If I add another 6.6Kw panels, it should be able to save 25Kwh per day in July. Based on that June and August will also be covered.
  
  Thanks for the suggestion on breaking down the savings on the battery and extra solar. I will run the numbers again to see if spending extra $2000-$2500 to get 6.6KW of panels is worth it.
biga1 on 15/10/2025 - 13:32

I’m in a similar situation to you and went with something close to option 2 (with only a 24kWh battery). Adjusting the quote for two less modules is inline with your pricing (top quality installer who I vetted, with in house staff and a 5 month install waitlist!).

Looking through all the options, it was pretty similar to just replace the existing panels and inverter (also 6.6 of panels and Fronius inverter). A little wasteful with more e waste, but panels have improved over time so it was better to get 14kW of new panels all covered by the one warranty (talking with a few installers, dc coupling older panels could have some warranty implications, if those older panels stop working your original installer likely won’t be interested if the new installer has rewired).

I am also separately doing a meter box upgrade. Why limit yourself to two circuits when these are capable of full house backup? If there’s a blackout, the battery is full and the sun is shining I want to choose what I use. Might be worth thinking about if you’re planning on being in the house for a while, cheaper to do it now than afterwards.
FoxJump on 15/10/2025 - 14:49

+1

and which of those are compatible with home assistant?
- BensonP on 15/10/2025 - 22:27
  
  +1
  
  Sigenstor is definitely compatible.
sacah on 15/10/2025 - 21:10

From what installers have told me, steer clear of Alpha gear, they've all struggled to get support for them when anything was needed.
TheOtherLeft on 16/10/2025 - 08:02

I'd ignore random installers you found on Facebook. Most are probably dodgy. Stick to an established business who uses their own tradies not subcontract out.
- lgacb08 on 16/10/2025 - 11:12
  
  Actually that's what I thought but I got mine installed via a local installer through their Facebook ads and they were top notch. Local guys, doing all in house, price was competitive, even got full house backup for next to nothing. I'm surprised they still have their ads pop up here and there when they already have 6 months of work ahead.
gyrex on 16/10/2025 - 09:27

+1

Steer clear of any quotes pushing a 5kW hybrid/battery inverter and seek quotes with 10+kW inverters instead.
Ryanek on 16/10/2025 - 10:33

I just want to say, this is a great example of a post asking for help.