I am new to this. I am on octopus Intelligent go and am wondering how much control I can over my system given that Octopus now has control of my battery. Is it possible to install home assistant to add more control. Appreciate any clarification on this point
If you are on intelligent Go then Octopus does not have control of your battery. It is a basic tariff with the possibility of having additional cheap slits at Octopus’s discretion.
Are you actually on Intelligent Flux, where you cede control of your battery to Octopus? If so then HA will be of little use to you in controlling your system, though it may be helpful in reporting.
If you actually are on Intelligent Go, then the world is your oyster! The ultimate geek toy atm is Predbat. Have a look at the online manual, but here’s a summary:
Predbat takes in as input
- your system setup (inverter(s) size, battery(ies) size, etc), often grabbed using the GivTCP integration
- your import and export tariffs (for many using the excellent BottleCapDave Octopus integration)
- a solar forecast, typically from Solcast
- your historical usage over the recent past, hour by hour, from HA
- details of your electric car, if any
- any other over-riding factors (eg Octopus Power-ups, Octopus Saving Sessions (it will auto-opt-in to these), holidays)
- a whole raft of parameters, which are used to change the weightings of the above in its determination of its outputs
The outputs are
- predicted load (based on historic usage patterns)
- predicted solar generation (based on Solcast, with the ability to be more conservative)
- a plan of when to charge/discharge in order to maximise income/minimise cost over the next [24] hours
- the ability to take control of your system and implement that plan (for Givenergy and a few other systems)
It’s a complicated beast, and is in active development. Tuning the parameters to get the result that works best for an individual case takes time and effort. But it is pretty impressive.
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Thanks so much for your input, it’s been most helpful.
I have the RP and was just about to download HA when I had a panic!! I was on Flux but have been on intelligent go the past month since getting a car.
Now you have clarified I can use HA I will set about setting it up and integrating Predbat. I am looking forward to the challenge with AI by my side!!
Good luck!
There is a very long thread over on the main forum where you can find many hints and get support if (when!) you need it - https://community.givenergy.cloud/d/3696-first-night-live-on-predbat/740
Predbat looks interesting, but from my perspective there is a critical flaw: if I’ve understood it right, it predicts household load from the preceding 10 days’ loads and sets up charge and discharge periods accordingly.
My load varies wildly from day to day and within a day: that’s what happens if you use an air-to-air heat pump to heat rooms which can benefit substantially from solar gain. So forecasts of load are worse than useless. Today’s Solcast for my panels had a median forecast of about 8 kWh but I actually generated 2 kWh: below the 10 percentile.
I’m therefore very keen on Eco mode which adjusts charge / discharge rates dynamically to respond to what’s actually happening. I want to be able to top up the battery during periods of off-peak pricing but only as and when I’m not going to have enough PV to see me through to the next off-peak period (which comes twice a day on Cosy Octopus - a considerable advantage but which adds complexity).
It’s certainly not for everyone. Though there are several A2AHP people using it.
There is a sister program by the same developer called Predheat, which I have never looked at. You may want to check it out here. On a quick glance it may be something that may be suitable for you when it has been developed a bit more. It doesn’t seem to be in active development.
As far as your points about Predbat:
- the load forecast is based on historic usage, but not necessarily from the last 10 days. This is parametrically defined - you could use 90% of yesterday and 10% of the day before, for example. Entirely up to you. Personally, I use up to 3 weeks data, with the last week and the current day of the week weighted more heavily.
- Solcast forecasts are indeed very noisy (and optimistic in my experience) in its predictions. Predbat addresses this by allowing you to parametrically manage the balance between Solcast’s 50% and 10% forecasts. And of course you are able to adjust these forecasts yourself by changing the efficiency setting within Solcast.
- Predbat contains a (clunky atm) mechanism for manual override, if you want to do so.
- Predbat dynamically adjusts its actions every [10] minutes depending on what is happening, and - for example - includes a parameter allowing you to increase the importance in the load forecast of the experience so far today should you choose.
Anyway, I am starting to sound like a fanboy, which is not my intention. Most people start off running Predbat in “monitor only, no action” mode, to see how it would work for them. If you have time and interest it’s quite interesting. 
Thanks PianSom.
Saturday and Sunday provided a good demonstration of the problems I face. Last week the weather and Solcast forecasts for Saturday and Sunday were very similar. Saturday morning’s forecast for Saturday was better than Sunday morning’s for Sunday. But whereas Saturday’s outturn was somewhere near the 90 percentile of Saturday morning’s Solcast, Sunday’s was at the 10 percentile.
Not only did this mean that on Saturday I had 13 kWh of PV compared with 2 kWh on Sunday, I estimate that the solar gain on Saturday reduced my consumption by about 5 kWh to 10 kWh.
The only way that I could see a prediction system working well for me would be if it had a reliable forecast of the amount of sun I’m going to get. That appears to be beyond the capabilities of current systems.
So I’m going to stick with Eco mode and learn how to modulate it so that if, for instance, I’ve not got enough charge stored to see me through 4 - 7 pm, I’ll turn off discharge in early afternoon so that I use grid electricity at standard price rather than premium price.
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Of course you should do what works best for you.
Though I am not surprised that the Solcast future forecasts are not stable. Let’s face it - weather forecasts generally are not stable! Looking at my own Solcast outturn for Sat and Sun, they are - like yours - radically different from where they started. But because the Solcast forecast is refreshed every few hours, and the battery charge/discharge plan is immediately updated to reflect the latest forecast, it doesn’t matter TOO much. The point is that the Predbat plan is dynamically changed.
(FWIW - for me Sat final prediction 31kWh vs 30.7kWh achieved; Sun 10.7kWh vs 6.7kWh)
And the same goes for load predictions. On Sunday, for example, my house load ended the day way exceeding the initial prediction (as the large Easter lunch got put in the oven and all the general family usage increased dramatically). In my Predbat that meant that the load forecast - which started the day thinking it was a normal-ish Sunday - changed during the day. And so Predbat cancelled an initially planned battery discharge at 7.30pm; just as well, since the battery got exhausted by consumption.
My suspicion is that if you are waiting for any kind of system that can accurately predict even a day in advance what will really happen to your PV input and load consumption then you are quite correct to be doubtful. But a system that reacts to variations from a reasonable base case dynamically depending on how things are developing is available (for free) right now.
I really will stop evangelising now!!
Thanks.
My impression is that Predbat sets up and manages the system using Charge Periods and Discharge Periods. Perhaps you could confirm this?
I don’t like Charge Periods and Discharge Periods because they have the effect of disabling Eco mode, i.e. the dynamic second-to-second adjustment of charge and discharge rates to/from the battery to meet Load and store any surplus PV. I tolerate them (I only use Charge Periods for now as I haven’t got surplus PV or an Export MPAN) because they’re the only way to take in grid electricity during off-peak periods.
My aim (for now) is to load up during off-peak periods with the grid electricity I’m going to need before the next off-peak period and otherwise run in Eco mode to/from the battery. I’m on Cosy Octopus so my off-peak periods are 4 - 7 am and 1 - 4 pm with premium-priced electricity from 4 - 7 pm.
As it’s more efficient to take electricity direct from the grid than storing it in the battery and then discharging it, I use a Charge Period from 4 - 7 am even if I’m not charging the battery then, so that the load during this period comes direct from the grid. I don’t do this in the afternoon off-peak period as I’m generating PV then and a Charge Period causes the battery to charge at the specified rate from PV + grid. So I manually modulate how much charge I take on by adjusting the length of the charge period.
It’s probably worth remarking that the demand for heat from my heat pump is such that it cycles on and off. At the moment the period is 7 minutes. In each cycle it ramps up over a couple of minutes to a peak, then there’s a slow decline followed by a rapid one as it goes to sleep for a bit. Needless to say, the heat pump dominates the aggregate load on the house (I use gas for cooking).
Yes, Predbat sets up charge and discharge periods, though it is hard to see why it would ever discharge if you have no export MPAN!
When setting it up one specifies inverter and battery conversion loss amounts, so it shouldn’t charge wastefully.
All I can say is, I tried it out and was (and am) generally impressed with the decisions it comes to. Without an export option it may be less useful, but if you have time and like tinkering then there’s little downside to giving it a go in “read only” mode.