Is Wonder Watt Any Good?

Hello All,
I have Hybrid Gen 3 inverter and 9.5kWh battery - all working reliably for _18months without any external automation on Octopus Flux tariff and good payback (just under £1,200/year 🙂)
Am planning on getting an EV in the next few months - useful feedback in another discussion has me focused on Hypervolt 3pro EV charger as it offers integration with Intelligent Octopus Go tariff.
My remaining question is how to stop the GivEnergy battery discharging to the car in the additional low price slots that IOG offers (I assume that for the core low price charging period I could just schedule this as a GivEnergy battery charge period with the native GivEnergy firmware)

Useful response from @DD suggest feeding the EV charger 'before' the CT clamp that is linked to the GivEnergy inverter.

I also stumbled on Wonder Watt as another solution and wanted feedback from users (current and previous):
-is it any good?
-how long does it take to set up?
-is it reliable?
-Is set up difficult - did you manage to get it right 1st time?
-is payback > cost?
-on Octopus Flux
-on IOG
-can I do set up once and forget about it or is this something that needs constant tweaking?
-Have you/would you stop using Wonder Watt? (& why)

looking at Trust pilot the reviews are very good (but some suppliers get friendly customers to right nice reviews) and the Wonder Watt website tells me that it is great. Their support pages tell me that it is not without issues, but hard to tell if this is once in a blue moon and quickly sorted or a recurring nightmare.

Seeking feedback.

daveharding100 A happy Wonder Watt customer here. I have 5.26kWp of solar, a 6kW Solis Inverter and a Givenergy AIO. I have been with WW for more than a year and I can say that it works really well. I was originally on Agile and that has had more and more functionality added on a regular basis, support is nothing short of outstanding, with the developers adding suggested features and squashing the inevitable occasional bug efficiently and promptly, on occasion within a few minutes of being made aware of it.
They offer a fully functional free trial so why not have a dig around yourself.

daveharding100 I do set up once and forget about it or is this something that needs constant tweaking?

I have been with WW for 4 months or so I have 2 x GE AIO's and I am on Octopus IOG. I run entirely hands off on standard WW schedules. The only time I touch it is when there is an Octopus Free Energy session, (as you never know the start time) I have a couple of spare schedules for this purpose, one to Export before the free session to make room and one to top back up again. These schedules go automatically dormant after use until the next time you need them. Any issues that you may have are dealt with quickly by support and there is a constant stream of new features coming along all the time.

The WW service and support is second to none IMHO and if you are looking for a automatic scheduling system that just works without constant management by you, then it will suit you down to the ground.

daveharding100 I am a WonderWatt user on Octopus Agile and WW helped me achieve the best return ever from continuously exporting and charging. This post shows how reliable it is...

https://community.givenergy.cloud/d/5303-for-those-of-us-thrashing-the-inverter/212

Every charge and discharge transition was a sequence of commands over the Inverter API from the WonderWatt server.

To get the most out of something like WonderWatt you need to be on a ‘more complex’ tariff such as IOG or Agile. A tariff with simple predictable cheap rate periods you can just set the charge schedule up yourself on the inverter. So for Flux, I wouldn’t bother.

One thing to be aware of is that all the cloud services such as Wonderwatt, My Energy Optimiser, Predbat.com, Octopus R&D rely on being able to send commands through the givenergy servers to your inverter. If there isn’t reliable comms from your inverter to the internet, if you get frequent timeouts when trying to set commands in the inverter, then none of these services are going to work well and you should fix the network issue first.

As others have said, WW works well, support is good, and there’s a free trial. Do your own calculation to work out whether it saves you the monthly subscription.

Update:

Have signed up to WW. After an initial glitch it seems to be working well (4 days). I am currently on a 'simple' tariff (Octopus Flux) and I seem to get 2 useful benefits:
1) resolves the GivEnergy bug/feature that disabled the battery when discharging and you hit the SOC% lower limit.
2) set and forget: given the above bug, particularly in winter, it is hard to get a schedule in the native GE scheduler that maximises export at peak rate AND is robust to lower solar power and/or high consumption days - WW gives you this.
In the spring I expect that the weather forecast feature will help optimise how much I charge up at night OR if I have an EV first then the it looks like it will help with IOG...

...based on 4 days operation WW looks like, even on simple tariffs, it at least breaks even financially AND simplifies operation.

There is one other alternative to Wonderwatt or Home Assistant, and that is the 'Inverter Monitor' app available on android. You need an old android phone or tablet, the app is free to use to monitor, or a one-off £10 payment if you want to use it for scheduling charging and discharging times. It also has the facility of being able to work directly with the inverter with or without internet.
Been using it nearly 2 years and it's been absolutely reliable. I've used it with both Flux and Cosy, and for the last 12 months Intelligent Octopus Go.
Apart from the initial one-off £10 cost, there is no monthly fee. Maybe worth a look if you're on Android.

https://givenergymonitor.wixsite.com/tutorials/connecting

Hi TimHutchings,

This looks intriguing. For one off £10 (+ a spare old phone) it looks like it fixes the GivEnergy bug 'disable battery at lower SOC% limit during discharge'. It looks like discharge is only requested if there is enough charge to start with. Is this correct?

Does it have a weather forecast function to intelligently look at tomorrow's likely solar generation and set the level of cheap rate overnight charge? In any case I suspect that for Octopus Flux, the lack of a monthly fee, I guess, means that it should at least match the WW for payback.

Question: you say that you use this with Intelligent Octopus Go; how does it cope with the extra intelligent EV charging slots? I started down the rabbit whole of external inverter schedulers because I wanted to prevent my GivEnergy battery from charging an EV AND to use IOG. I understand that WW will do this for me. Does this Inverter Monitor have a solution for this? (I am planning an EV purchase and I think that I have 2 solutions in the bag - WW and a nice one here https://community.givenergy.cloud/d/6247-benefits-of-givenergy-ev-charger/13 from @DD to locate the GE CT clip 'after' the EV charger feed - a 3rd solution would do no harm 🙂)

daveharding100
Lots of questions which would probably be better directed to Rubikube who wrote the app and posts on this forum. However, I can answer some of the points you make and I'll tell you how I use it for Intelligent Octopus Go.
It's not as sophisticated as Wonderwatt or Home Assistant. It simply uses scheduling to charge or export from your battery using times, percentages etc to achieve what you want.
There's no forecasting of weather or Intelligent charging or discharging at odd times like DFS saving sessions, or IOG cheap sporadic charging periods when charging an EV outside the set charging periods.
However it does work really well with IOG for me. That particular tariff of 7p import between 11.30pm and 5.30am works really well as I charge my battery at 7p fully overnight, set the dishwasher and washing machine to run at the same time and charge the EV when it needs charging. During the day all surplus solar is exported at 15p, and any solar left in the battery is exported during the evening at 15p using the Inverter Monitor. I've set a schedule in the app to check every half hour using percentages on the battery SOC and start exporting so it's virtually empty at 11.30pm ready to start charging again.
I had my Zappi EV wall point CT clamp positioned so the inverter can't see the car, so it doesn't draw from the solar battery to charge the car (unless the car happens to be charging at the time when I'm exporting surplus battery!). It also doesn't make sense to charge the car with surplus solar export at 15p while I can import charge for both EV and solar battery at 7p.
Hope this helps!
For the last 3 years I've had my system, including an A2A heatpump for house heating, and including this last year I've had an EV, my net total Energy bill to Octopus has been Zero, including gas and all standing charges and EV charging on IOG. I have a 5.46kW solar array, a 5kW gen1 inverter, and a 9.5kW battery.
Works for me!

Happy WW customer here using Intelligent Octopus Go with an EV, can report that WW does indeed resolve the accident discharge of batteries into EV issue nicely, if it detects an 'off-peak' slot triggered by your IOG EV charging schedule, it automatically charges the batteries during the cheap rate slot.

I personally, don't utilise this function very often, doing almost all my EV charging in the standard 11:30pm - 5:30am IOG slot, but it is nice to know it's there when plugging in during the day.

It has all very much been set and forget so far, though I am wanting to move to a local automation in due course, as spending £0/year to do is better than spending anything/year in my book.

I was looking at Speak to the Geeks HA integration as a way of doing the same thing, locally and for free, but have yet to implement: [https://www.speaktothegeek.co.uk/2025/02/charge-givenergy-batteries-during-intelligent-octopus-go-cheap-slots/]

daveharding100 The app I wrote is intended to be simple, giving the option of local control. It doesn't do weather forecasts and isn't great for Intelligent Go. It was never intended to compete with HA/Predbat nor WonderWatt, nor even the GE app/Portal. You can read how it came about here

https://givenergymonitor.wixsite.com/tutorials/about

Hi Rubikcube,
Nice story and the app looks nice...
...it amazes me that on a 'few rainy days' it looks like you have done a better job than GivEnergy! (4.6 stars and over 1000 downloads - they get 2.2 stars)