Last week I was in Officeworks waiting for some printing. Next to me, a woman was buying a laptop, and the Officeworks bloke helping her knew his stuff. Processors, RAM, screen brightness: all of it correct. Then he asked whether she’d considered a Mac, which opened a second long conversation about MacBooks, and by the end of it, she looked more confused than when she started.
He left her to think it over. I couldn’t help myself.
“Excuse me. What kind of phone do you have?”
She gave me the look you’d expect from a stranger in Officeworks. Then: an iPhone. And an iPad she uses all the time.
In that case, I said, the Mac is a no-brainer. Your photos, messages, passwords and files will just turn up on it. That will matter more every single day than which chip is inside or how many nits the screen pushes out.
I don’t know what she bought. But I walked out thinking about how often I watch the same conversation happen with home batteries, and how rarely anyone asks the equivalent question.
Nobody asks what you already own
Post “which battery should I get?” in any Australian solar Facebook group and you’ll have thirty replies within the hour. Most will name the brand the replier bought. A few will argue about dollars per kWh. Someone will bring up cycle life. Almost nobody will ask what’s on your roof, what inverter it’s plugged into, whether there’s an EV in the driveway or what appliances you need to power, and which of those need backup.
Many professional salespeople aren’t much better. Plenty of the quotes I see are a battery bolted onto whatever was already there, powering mystery loads. The battery model chosen because it’s what the installer likes to install.
Where possible, buy the same brand inverter, battery and EV charger.
What matters is whether the battery can play nice with the existing solar inverter, how much solar you’ve got, and what loads you need to power.
If you get three boxes from three companies, each optimising its own corner, it’s a mess. The EV charger doesn’t know the battery is nearly flat. The battery doesn’t know the 7kW load it’s just seen is an EV that should be left to charge from a cheap grid tariff. You get three apps and about a million CTs in your switchboard, all measuring the same current, all points of failure.
Sungrow inverter, Sungrow battery, Sungrow EV charger. Fronius hybrid inverter with a Fronius or BYD battery and Fronius Wattpilot EV charger. Sigenergy stack with Sigenergy AC EV charger. Enphase? If you can wait till 2027, their new battery and EV chargers look like they’ll finally be worth buying.
How much solar you own matters too
“What do you already own?” also tells you whether you need more solar. A 6.6 kW system from 2016 will not fill a 20 kWh battery in June in Adelaide, never mind charge an EV on top. Sometimes the right answer to “which battery” is “more panels first”.
What solar you own also tells you whether to AC or DC couple. A top-quality inverter with years of warranty left points to AC coupling: leave it alone and add a battery beside it. An old string inverter from a brand that has abandoned the lucky country points to DC coupling with its own solar inverter.
Careful, some ecosystems die
I started with an Apple analogy. That has a limit.
Apple will still be around when that lady’s MacBook, iPhone and iPad get recycled. Inverter brands have a worse record. I’ve watched dozens go broke or leave Australia since I started SolarQuotes, and when a brand goes, its app, its cloud, its firmware updates and its warranty all go together. Putting your inverter, battery and charger with one company only pays off if that company stays alive and kicking in Australia.
So buy one ecosystem, and make it a brand with the balance sheet to still be here in 2036. That narrows the field to the big names, and I’m fine with that.
How to filter installers
If you’re buying, choose an installer who asks what’s on your roof, which inverter it’s connected to, what car is in the driveway or on order, and what loads you want to power – under normal circumstances and during a blackout.
If nobody’s asked you yet, you haven’t met a good installer.
About Finn Peacock
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“A 6.6kw system in Adelaide will not fill a 20kwh battery in Adelaide in June”
True, but it will in January.
As many panels as you can afford/cram onto your roof for Winter and as big a battery(s) you can afford/fit in your space for Summer.
Interesting that none of the solarquotes recommended installers had asked me those questions, nor did they educate me the different batteries could be connected in parallel or in series with the grid.
These 2 articles would have been helpful when I went through thr electrification journey.
I am a lot more aware and educated now, at the expense as self discovery.
We have Enphase on the roof (surrounded by trees) but waiting until 2027 wasn’t a realistic option for us. Our Solar Quotes-sourced installer recommended we attach a SigEnergy battery and AC charger system. We are very happy with the outcome as the two systems are working very well together.
Hi Michael
Can you tell us how old your Enphase system is and a description of your system. I have 24 S230’s on my roof since 2017. They have all operated perfectly since then, however Enphase say that they are not compatible with their IQ 5P battery due to a change in communication methods.
They send far too much back into the grid.
Hi Trevor,
I have 3 solar systems on my roof, one of which is 6 x QCells panels with 6 x S230 microinverters, installed October 2016, working without incident. I went with a Sigenergy battery 4 x Bat8.0, installed December 2025 and it working well.
Hi Trevor,
Thank you for sharing your system details. Your existing Enphase S-Series microinverters are compatible with the Enphase Energy System, including the IQ Battery 5P FlexPhase, IQ EV Charger, and IQ Energy Router.
The IQ Battery 5P features six built-in microinverters and PowerMatch™ Technology, delivering excellent efficiency, reliability, and performance.
Learn more: • Enphase Website Link: https://enphase.com/en-au/installers/storage/gen3-flexphase
• Video: https://www.youtube.com/watch?v=qjaJD5rDwZc
Enphase is also advancing solar technology with its latest IQ9N™ platform, which incorporates Gallium Nitride (GaN) technology to deliver higher performance and efficiency while maintaining reliability.
Learn more here:
• https://enphase.com/en-au/homeowners/home-solar-systems
For further information, please call 1800 006 374 and select Sales Enquiries.
The question I never got asked was do you have mobile phone reception? I don’t and my very expensive battery will never pay for itself because all retail electricity plans require your meter to have mobile reception.
Ouch, very ouch.
Time to weigh up the cost of a roof mounted Yagi antenna pointed at the nearest compatible mobile tower?
Alas it’s not a case of poor mobile reception – there is zero mobile reception here. None. Only choice is a Cel-fi system but it’s several 1000 dollars with no guarantee it will work, sigh.
Back in the day when I worked for Optus they sold a device called a femtocell. It connects to your router by ethernet and acts as a low range, indoor cell tower. They were about the size of a normal wifi router. I don’t know if any of the telcos currently sell something like that but it might be an option to investigate.
Knowing which Telco and what 4G bands your remote power monitor uses is probably vital to getting a compatible femtocell if they still exist.
Thanks David but apparently not. went the way of the dodo and 3G it seems. AI: “You cannot buy a femtocell in Australia today because major mobile network operators no longer offer or support them, and unauthorized broadcast hardware is illegal”
Hi Rod & David,
It’s not my field but the last I heard Telstra offered the Cell-Fi-Go as a low power phone repeater.
There are fixed and mobile versions for vehicles.
Or if you speak to someone who services remote area customers I’m aware of fixed reciever/repeater solutions which might involve a concrete footing and a tower.
I endlesly read of people who.mix and match inverters and batteries based on reviews of one or the other. To their peril. Then moan amber does not work for them. It certainly wont.
The cost per kwh is most important. Pick the wrong one and its two times the other. You are paying double for the same thing. When saving on energy was the aim. For a brand name like Tesla.
And the cheapest part of the system are the panels.. Old panels may still work but so may a 1953 austin minor. 200w v a modern 500w. And just 8 of them is useless. Ask the quoter about the merits of starting with new panels. Adding a 1953 austin monor engine to your new bmw wasnt a option and old panels may be the same.
And…dont rely on old products. The industry and products are rapidly evolving.
You don’t need to buy solar panel technology from 15-20 years ago even though they still work. I sourced recent solar panels of about 400-415 watts off people who were upgrading their systems with a battery. If you want to be able to boast at the next BBQ that you just installed a Tesla battery (and probably overpaid lots and the fire risk from NCM battery chemistry) good on you. There are much better options available if you do sme research. And the old adage is always true, you can’t have enough solar. Your new BMW system will be dated within a year and it only goes down from there. As far as I am concerned, big solar to cope with the worst weather and way bigger battery than you think you may need, then you should be sweet. You need to educate yourself and not just listen to these installer companies who are just trying to make money while the sun keeps shining, if you know what I mean…..
Just a heads up for anyone with a 2 phase supply….I live on the Sunshine Coast Hinterland on a rural property which is why I have a 2 phase supply. My supply from Energex needs to be converted to a single phase supply because of phase indifference. As I am installing a 10kw hybrid (sungrow) inverter. Regulations state that you are only allowed 5kw phase difference. By removing a phase, I can have a 10 kW inverter because I also have a battery (30kWh Sungrow)
Solar quotes team, you may need to clarify and expand on this to the punters.
FYI, I utilised Solarquotes quotes tool and are very happy with the recommendations. I have chosen CDC solar for my upcoming installation.
Good read. I actually had a question. Is it possible to charge a battery normally and then use the charge to fast charge an EV, like how it’s being done for byd MW charging, obviously not those speeds. But maybe could be a cheaper 100kw home charging system?
I think the Sigenstor DC charger on their battery stack can push a fair bit of juice into your car. That’s what I’d be jumping on to charge my EV if I wasn’t so price sensitive.
Keep in mind though that the house battery is probably a fraction of the capacity of the car battery, so the benefit will just be putting maybe 20 or 30% extra range in the car in a short time.
If you want home DC charging like what Sigenergy is offering, you’ll need a big roof full of solar panels (+20kW worth) and charge your EV with excess solar after your battery has been fully charged.
While you can use your home battery to DC charge your EV, it’s not practical. Your EV is has far bigger capacity than your home battery.
But then if you can afford all that, why not.
However a 22 kW AC charger can deliver the same at lesser capital layouts
We recently ordered battery and invertor to better use the solar we donate to the grid.
The installer asked what we’ve got. We chose a different brand battery/inverter and we had reasons for this.
Apparently brand is not such a big deal because they are AC coupled.
I use an iPhone because I get hand me downs from my wife. She uses a Mac, I use a PC (Windows or Linux). I’ve been using a PC for over 30 years.
I can’t use a Mac, they are totally foreign to me and what I can do in seconds on a PC takes me forever to work out how to do it on a Mac.
Ron,
Yes, what we’ve learnt over decades is a powerful enabler, not to be given up for a spot at the bottom of a new learning curve. I just stick to Linux, after decades of exclusive use. So it wasn’t only price which steered me from Selectronic to Victron: VenusOS, which runs on the Cerbo GX Victron touch-screen system controller, is Linux based. That makes it available for tweaking. (And opening a browser tab on the PC on my coffee table, for Remote Console system access. is super convenient.)
One could retrofit SoC reporting from the Jikong BMSs on my generic LFP house batteries to the Cerbo GX, but I get by with the Jikong phone app. And the Victron Smart Shunt coulomb counter tracks SoC adequately without total system integration, so it all works fine as is.
Our 10kw battery meets our evening needs (just). But our 6kw inverter is a bottleneck that slows up the 22 panels from filling the battery, so we run into problems in winter and still pull grid power in peak. Not as much as no battery of course, but an upgrade will help
The Apple analogy no longer applies to phones and PCs. They can easily talk to each other with photos transferred to my PC in the background without any effort and my passwords and files created on the PC available on my phone. It wasn’t always like that.
How long will it be before solar PV, home batteries and car chargers are like that and are able to work together?
Should there be incentives for companies to make systems compatible?
There’s nothing like an integrated system controlled where the devices communicate to one another seemlessly. Add in remote monitoring & support, where device firmware is updated behind the scenes. And in one app provides your systems performance.
Yes, I am talking Enphase.
Finn,
Great article – punchy, useful advice, easy to read.
Your classic “Fill the roof” suggestion still reigns supreme, as generation beats storage – a steady 2 or 3 kW from 20 kW of arrays, in three days of overcast, can power the house’s average load, while the battery handles peaks, without ever being enough for the murky half week.
On grid, that’s not essential – until the grid goes down. Some years ago, our Dandenongs grid was down for 5 weeks – in winter. Portable generators had sold out. Five weeks without a HWS, and one camping stove burner for cooking is an experience worth missing. Yep, no fridge, either.
Yeah, nah. It won’t happen … until it does.
Firstly thanks for your articles. This site was wonderful when choosing a battery and what I needed to know. I got a good installer that answered all my questions well.
Under the heading “How much solar you own matters too” I think there is one important point missing on this topic.
I have had a 24kw Sigenergy battery installed to an older 5.5kw solar panel system which was installed in 2012. We have no more room facing north for solar panels. BUT we don’t need more panels to charge fully each day even in winter in the Illawarra where the escarpment means short days and a hill in winter which makes solar period short.
THREE HOURS FOR FREE is a game changer. Even on winter days with rain and clouds and very little solar we would charge at 6.6kw for 3 hours nearly filling the battery. Also I would get free power on top for that from 11am to 2pm.
Now spring is here solar is topping up the battery around 10am to 3 so getting a full battery.
So don’t need more panels with 3 hours free.
I’m thinking of buying an Electric Vehicle capable of also acting as V2H. I have 6kW Sungrow Panels and Inverter. I can’t find any real commentary about compatibility. Any thoughts would be welcome.
Thanks
Evan
Hi Evan,
Sungrow now offer their own AC car charger which involves installing an iHome manager in the switchboard to make it play nicely.
Some brands like Fronius are offering AC bi- directional charging with the Wattpilot Flex, however there’s not much news about when or if the standards & DNSP rules will be harmonised enough to get AS4777 certification on the car and network connection approval.
What is available off the shelf right now is basically a generator inlet socket for your house.
The HOEM device means you can run things like fridge, lights, internet & maybe a split system air conditioner from your EV.
You have to select which cable to use for charging or discharging, it doesn’t swap automatically, but it doesn’t endanger your EV warranty.
Thanks for your informative response Anthony. Surely other EV manufacturers will see the opportunity of V2H and V2G. and put some on the market.