Wonder Watt now supports six inverter brands, including Solis and FoxESS
Two of the most requested integrations are live. Solis and FoxESS now join Growatt, GivEnergy, Solax and AlphaESS, which takes Wonder Watt to six supported inverter brands.
If you own a Solis or a FoxESS hybrid system, you can now get predictive, forecast-led battery charging without running a home server, without writing YAML, and without leaving your battery on a fixed timer that ignores tomorrow’s weather.
Which inverter brands does Wonder Watt support?
Wonder Watt supports six inverter brands: Growatt, GivEnergy, Solax, AlphaESS, Solis and FoxESS. All six connect through the manufacturer’s own cloud API, so there is no extra hardware to buy and nothing to install at your property.
We have put together a permanent supported inverters page listing what works with each brand, what you need in order to connect, and which models our users have confirmed as working. That page is the one we will keep updated as the list grows, so it is worth bookmarking rather than this post.
Why did Solis and FoxESS take so long?
Because inverter APIs are the bottleneck, not our software.
Every integration we ship depends on the manufacturer exposing a documented cloud API that allows a third party to read live system data and, crucially, to write schedule and charge instructions back. Plenty of manufacturers offer the first half and never the second, which is why monitoring apps are common and automation apps are rare.
Solis and FoxESS have both matured their cloud APIs to the point where proper control is possible, and that is what unlocked these integrations. Getting there took a fair amount of testing against real systems, which is the part that does not show up in a release note.
It is the same point we have made since we started, and it is worth repeating for anyone still shopping: ask the manufacturer whether they offer a public, documented cloud API with control endpoints before you buy. Open APIs are what make a smart ecosystem possible. Closed ones leave you stuck with whatever the vendor’s own app happens to do.
What do Solis and FoxESS owners get on day one?
The same core Wonder Watt service our existing users have been running for years:
Forecast-led charging. Our in-house solar prediction algorithm works out what your specific array is likely to generate, then decides how much grid charging you actually need overnight. If tomorrow looks bright, you do not pay to fill a battery the sun was going to fill for free.
Multiple, conditional schedules. Build rules around state of charge, forecast yield, price and time of day rather than one blunt overnight window. Our multiple schedules feature covers how this works.
Smart tariff support. Our Agile Octopus integration picks the cheapest half-hourly slots for you and re-plans as new prices land.
Timed and dynamic export. Force discharge or export into peak pricing when it pays to, then return to normal operation automatically.
Gentler on the battery. We adjust charge rates rather than hammering the pack, and we skip charges you do not need, which means fewer cycles over the life of the system.
Do I need Home Assistant?
No. Wonder Watt is a hosted web app, so there is nothing to install and nothing to maintain.
This is the reason a lot of people find us in the first place. Home Assistant with Predbat is genuinely powerful, and if you enjoy running a Raspberry Pi and tuning config files then it is a great option. But it is a rabbit hole, and it is not a reasonable ask for most battery owners who simply want the thing to make sensible decisions on its own.
You need a browser and a Google account to sign in. That is the whole setup.
What is coming next
Three things worth flagging, since they all landed or are landing around the same time as this release:
Our solar algorithm now updates more granularly. More frequent forecast revisions through the day means charging decisions track the actual weather rather than yesterday’s guess at it. We will write this up properly with worked examples.
Axle integration. Your battery can now earn money by supporting the grid during flexibility events, scheduled around your solar forecast and tariff plan rather than in conflict with them. A full write-up is coming, including how this interacts with each Octopus tariff.
Wonder Batt. A fully automated, genuinely hands-off mode with no schedules to configure at all. Currently in development and launching soon.
To get started, all you need is a Google account. No upfront payment details, no hidden costs, and 14 days to decide whether it earns its keep. You can find our pricing information here.
Running a brand we do not support yet? Tell us in the community forums. Demand genuinely shapes what we build next, and Solis and FoxESS are the proof of it.