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.

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After the success of our Agile Octopus integration over a year ago, we’re pleased to announce public availability of our Intelligent Octopus Go integration.

Intelligent Octopus Go is one of Octopus Energy’s smart and innovative tariffs, offering customers with an EV a standard 23:30-05:30 off-peak window at 7p/kWh, but on top of that, it also offers you smart adhoc charge slots at the cheaper rate when you plug your car in.

This allows users to benefit from Octopus smart tariffs and automation without using Home Assistant. A rabbit hole that clearly is not suitable for everyone.

Users of Growatt, GivEnergy and Solax systems with PV battery storage can take advantage of this integration by charging their battery and getting the same cheap rate as the adhoc charge slots that Octopus has assigned via their IOG tariff.

Our IOG integration has been in closed (opt-in) beta since the summer of 2024. We have been able to improve the integration and feel now is the right time to make it publicly available to all our users.

You will find the Intelligent Octopus Go integration page under the Octopus submenu, then Intelligent.

Note: You will need either a compatible EV charger or an EV that Octopus can control. As long as you can see your mapped IOG charges in the Octopus app. This means we can access your smart charges via the Octopus API so we can send appropriate inverter instructions.

You can find our pricing information here, but you can sign up for a 14 day FREE trial, no payment details required.

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Today, Wonder Watt is launching a smart and predictive charging solution for users with Solax inverters and battery systems. This makes Solax our third successful inverter integration after Growatt and GivEnergy.

Wonder Watt uses its own in-house solar forecast prediction algorithm, to prevent unnecessary charging, as well as supports Octopus Energy’s smart tariffs like Agile, Intelligent Octopus Go (IOG) etc. via a modern and easy to use web app user interface.

This new integration means users of Solax inverters now have an intuitive way of setting up multiple schedules for charging from the grid as well as dynamic schedules for forced discharging/export.

In addition, our work on Agile Octopus integration is supported now for Solax too.

Inverters like the Solax X1 and flavours thereof are confirmed to be working. Others are likely to also be compatible.

To get started, all you need is a Google account. No upfront payment details, no hidden costs.

Don’t like it, don’t use it. We give you two weeks to work out whether our service helps you out or saves you time.

We’re always open for suggestions, so in any case, please let us know in our Community Forums.

We already support Growatt and GivEnergy, so Solax is our third integration, with more to follow still!

With our in-house built solar forecasting algorithms we calculate solar yield for your installation and use that information to charge your battery during off-peak/TOU tariffs (like Economy 7, Agile Octopus, Octopus Flux or Octopus Go) or export to grid depending on the tariffs and settings you have specified.

Take a look at the explanation of our Service Dashboard, and sign-up for free 14 day trial.

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Updated November 2024, to reflect reduced referral fee.

Are you considering purchasing a Tesla in the UK or US? Now might be the perfect time to make your move.

Tesla has just relaunched its ‘Refer and Earn’ program in the United Kingdom and the USA, offering new buyers a substantial £500 or $500 discount on their purchase. People referring get £250 Tesla shop credit.

The discount code willem775252 also applies to US customers and the same referral code can be used. Model S, 3, X and Y are all eligible for the discount.

This article will guide you through everything you need to know about this offer and how you can take advantage of it.

The £500 Tesla discount: What you need to know

Tesla’s new referral program is straightforward: use a referral code from an existing Tesla owner when you purchase your new Tesla, and you’ll receive a £500 discount off the purchase price. It’s that simple. This discount applies to any new Tesla vehicle orders.

You can simply click the button below when booking a test drive or before placing your purchase and the £500 discount should be applied at checkout.

Additional savings: 0% APR financing

To sweeten the deal even further, Tesla is currently offering a 0% APR financing deal in the UK on a Model Y. This offer includes:

• 0% Annual Percentage Rate (APR)
• Zero down payment on Hire Purchase plans

Combined with the £500 referral discount, this financing option creates an incredibly attractive package for potential Tesla buyers in the UK.

Why Now is the time to buy a Tesla in the UK

1. Immediate Savings: The £500 discount is applied directly to your purchase price, providing immediate savings.

2. Favorable Financing: With the 0% APR offer on the Model Y, you can spread the cost of your Tesla without incurring interest charges.

3. Long-term Savings: Don’t forget the potential savings on fuel and maintenance costs associated with electric vehicles.

4. Environmental Impact: By choosing a Tesla, you’re contributing to the reduction of carbon emissions and supporting sustainable transport.

5. Future-Proofing: As the UK pushes towards greener transportation, owning an electric vehicle may provide additional benefits in the future, such as exemptions from certain urban driving charges.

Maximising your Tesla purchase

To get the most out of your Tesla purchase, consider these tips:

1. Research Models: Explore the different Tesla models to find the one that best fits your needs and budget.

2. Calculate Total Savings: Factor in the £500 discount, potential financing savings, and long-term savings on fuel and maintenance.

3. Check Charging Options: Research charging infrastructure in your area and consider home charging solutions.

4. Test Drive: If possible, schedule a test drive to experience Tesla’s performance firsthand.

5. Act Quickly: While there’s no announced end date for this program, such offers don’t last forever. If you’re seriously considering a Tesla, now might be the time to act.

Conclusion

Tesla’s new referral program in the UK offers a compelling opportunity for potential buyers. The £500 discount, combined with the current 0% APR financing offer, makes this an optimal time to consider purchasing a Tesla.

Don’t miss out on this chance to join the electric revolution and drive home in your new Tesla – with an extra £500 in your pocket.

Disclaimer: We do get £250 Tesla shop credit for each referral, up to a maximum of 10 referrals. After that, the referral code cannot be used anymore.

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A new chapter for Wonder Watt: Introducing our subscription model

UPDATED 02-OCT-2024: Included details on Annual Subscription plan

Over the last year and a half, Wonder Watt has been a true labour of love. What started as a vision to offer an innovative and easy-to-use solar battery management service has blossomed into a thriving platform, thanks to the incredible support from all of you, our loyal users.

We have grown together, and your feedback in our forums has shaped Wonder Watt into what it is today. Every comment, suggestion, and experience you’ve shared has really helped us to improve.

However, as our community and user-base has grown, so have the costs associated with running the platform. Maintaining the high level of support and continuously developing new features requires significant resources.

After much thought, we’ve decided that in order to keep Wonder Watt sustainable and growing, we’ll be moving to a subscription model starting from October 2024.

What does this mean for you?

Beginning October, users will be asked to subscribe to Wonder Watt for ongoing access to our platform at a price of £6 per month. Users who joined before October are eligible for the discounted 3-monthly plan.

Below are the 3 subscription plans we will be offering:

Subscription Type	Billing Cycle	Discount	Monthly Price	Total Cost
Wonder Watt 3-Monthly Sub	3-months	None	£6.00	£18.00 per 3-months
Wonder Watt 3-Monthly Sub (Discounted)	3-months	11% Discount	£5.33	£15.99 per 3-months
Wonder Watt Annual Subscription	Annual	25% Discount	£4.50	£54.00 per year

No-quibble full-refund within 7 days of purchase.

Refunds requested after 7 days but before 6 weeks will be refunded proportional to the time left in the subscription.

No refunds after 6 weeks - access of service will continue until end of subscription term.

A refund can be requested by dropping us an e-mail here and request a refund. Make sure to report your WattID identifier so we can identify your account.

Why are we doing this?

We’ve been able to offer Wonder Watt for free up until now, but as we continue to expand our services, improve our infrastructure, and launch new features, it’s simply no longer feasible to cover all the rising costs ourselves.

Moving to a subscription model ensures that we can keep providing the best possible service without sacrificing quality. This will also enable us to keep building new tools and features for you - whether it’s enhanced energy tracking, more inverter and tariff integrations, or more autonomous schedules to help you save.

How will payments work?

To minimise processing and admin fees with our payment provider, we will be taking payments on a 3-month advance basis, or annual sub in advance which helps reduce costs and allows us to keep our subscription prices lower.

This means you will be billed £17.99 for 3 months at the full price, or £15.99 for 3 months if you qualify for the discounted rate. Equivalent pricing in USD will be available for anyone outside the UK.

If you choose the annual sub at the best discount, you’ll be paying £54 for 12 months, offering you an effective 25% discount on the regular 3 month subscription.

Can new users try the service out first?

Starting in October 2024, new users will have access to a 14-day free trial—no payment details required. You’ll be able to explore our features and see how Wonder Watt works for you.

If you’re happy with what you see, you can start a subscription when your trial ends.

Thank you for your support

We can’t express enough gratitude for the encouragement, feedback, and patience you’ve shown us over the past year and a half.

Rest assured, our level of support will remain as strong as ever. The shift to a subscription model allows us to keep delivering top-notch service while continuing to innovate and enhance the Wonder Watt experience.

We’re excited for this next chapter, and we hope you’ll join us as we continue to evolve. Thank you for being part of the Wonder Watt community — it’s been a remarkable journey, and there’s so much more ahead.

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