Automate changing Battery Reserve level

We're on Octopus Flux Import, with optimal import rate from 02.00-05.00 and peak import rate from 16.00-19.00. Our preference is to prefer self-consumption over grid export. (Export is still on FIT for the time being as we use the vast majority of our generation.)

Currently we have a timed import slot from 02.00-05.00 to charge the battery to 100%, and I manually toggle the "battery reserve" setting to 4% (i.e. full drain) just before 16.00, and then to 50% at bedtime (to allow headroom for solar charging during the day). The battery fully charges overnight then drains to 50% in the morning. Eco Mode is ON to allow the battery to top up from solar during the day.

Could anyone advise the simplest way to automate changing the battery reserve setting?

The manual process functions exactly as I'd like, it's just a bit of a pain. Could I maybe write a script to fire off the API calls at the right time & host this somewhere online? If Home Assistant is the best option I guess I'll just have to jump down that rabbit hole, but thought I'd see if anyone had any suggestions which don't require additional hardware.

Thanks!

Are people allowed to be on flux import only? I thought you had to have both the import and export tariff the same. Might get kicked off flux import if they spot that???

Home assistant is the best way to automate such stuff.

Wonderwatt might be worth a look too, although not sure if they support flux yet.

You can do it with powershell or python too, but with such a big home assistant community you might find that the best place to do it.

Have a look at YouTube to get started - search for speak to the Geek. Lots of videos on home assistant and GivTCP.

Ned Hmm... I'm a little surprised Octopus allowed you to have Flux, since it's a paired import and output tariff, but you aren't really using the export side. (Though I do get confused - one part of FIT is being paid for generation, and a separate agreement is payment for deemed export, but you can choose to go for measured rather than deemed exprort ?) Flux seems to be selected by those with more export than import, which doesn't seem to be your situation..? Just wondering if Agile is better ..?

Anyway... from your description, it sounds like you are trying to ensure that you have enough battery at 4pm to ensure you get through the peak-rate period with minimal import. What you are describing can very easily be implementing using trivial scripts to make API calls at the right time. But as you say, you'd need to get them hosted somewhere.

wonderwatt.com is one external agent that can control your inverter via the API. Your specific usage probably isn't something they already cover, but if it sounds generic enough, they might add support. @Wonder Watt ? They do already support Agile tariff - if that's a better fit for you anyway, then that might be an option.

Octopus R&D have a facility for running automata - I did register for an account there, but couldn't figure out how to make it do anything useful. But since I already have an always-on raspberry pi at home, it's trivial for me to run my own scripts there. [I would offer to run scripts for you too, but that can cause all sorts of security complications.]

I think there do exist cloud services which give you free low-powered virtual servers. I did briefly look at one of them (was it Oracle ?).

(IMHO home assistant is total overkill for a simple job like this...)

Ned I think there's a simpler way to implement your goal, assuming you have a modern inverter with multiple charging slots. If you configure slot #1 to charge to 100% from 0200 to 0500, and slot #2 to charge to 50% from 0500 to 1600, that should give you:

• charge to 100% overnight
• allow the battery to cover consumption before 1600 until it runs down to 50%, but still allow it to top up from solar
• from 1600, allow battery to discharge down to the reserve of 4%

When you enter a charging slot with the SoC already higher than the target, it just allows the battery to discharge as usual until it gets down to the target, then holds it there. I'm pretty sure it will still allow solar charging to go above that, but I'd want to experiment to make sure. (Sun has done for the day here, but I can test that tomorrow.)

Even if your inverter only has one charging slot, multiple charging slots is something that wonderwatt.com can do.

Ned Ned I too am surprised you are on Flux import only.

I have a FIT array as well as my new Givenergy inverters. As part of processing my Flux application Octopus spotted I was on FIT and advised that I would have to give up my FIT export to be on Flux. I think it might even be in the Flux FAQ or terms and conditions as its a paired import & export tariff.

Oh and by the way, unfortunately once you get a smart meter you are required to go onto measured export not deemed export, its in the FIT terms and conditions (which I didn’t personally know about until I was actually giving up my FIT export).

To be honest Flux is not a great tariff if you are not exporting as the import rates are relatively high. Tracker, agile (although this requires active management such as Home Assistant or Wonderwatt) or an EV tariff if you have an EV would be better.

DD I'm pretty sure it will still allow solar charging to go above that, but I'd want to experiment to make sure.

Hmm.. no, doesn't seem to work like that... I just tried setting a second charging slot from 1000 (now) to 1100, with a target of 30% (current SoC is 47%), but it didn't seem to want to charge the battery from solar. Turning back off the timer, and it resumed charging the battery from solar.

(But that does give yet another way to inhibit solar charging... )

DD Excuse me for chipping in. I have a recently-installed Gen3 5kW Inverter, with 19kWh of batteries and 24 East-West-facing solar panels. I am waiting for the export MPAN setup, but in the meantime have switched to Flux import.

While I was experimenting, I set an overnight charge from 00:00 to 04:00 to get the batteries to 60%. After a particularly good sunny day, there was more than 60% still present, but the inverter sent that out to the grid and brought the batteries down to 60%. No export tariff yet, so that was free power for the neighbours. Now that I am properly on Flux Import, I changed the charge period to 02:00 to 05:00 but still check around midnight to see if the batteries are likely to be higher than 60% or not. I have Eco mode enabled, so most of the day everything behaves itself, though the recent sunny days have still seen the batteries at 100% with more free exporting. Mind you, I'm quite pleased to see over 6kW of generating sometimes.

I have looked at setting a second Charge Slot, but can't see how to do that. There isn't an Add Slot button that I can see.

DavidBriggs I have looked at setting a second Charge Slot, but can't see how to do that.

It's only offered through the 'remote control' section - the 'gears' icon from the inverter page. That should give you 10 charge and 10 discharge slots (assuming firmware is up to date).

I can't immediately see why the battery should have discharged out to grid - that usually only happens with timed export / timed discharge.

The additional charge slots are only visible in the portal as @dd says, not the app. Maybe one day they will be added

The premium version of this android app allows you to change the reserve level on a schedule, although that is not the way I would recommend managing Octopus Flux.
https://givenergymonitor.wixsite.com/tutorials/tariffs#flux
Additional hardware is required if you don't already have an android device.

DD

DD Thanks for that suggestion. I can see them now. I just don't have a clue what to use them for (yet).

I was avoiding stuff that looked extra techy while I am getting used to the new system. Remote Control is one of those.

DD I can't immediately see why the battery should have discharged out to grid - that usually only happens with timed export / timed discharge.

I will have another look at this if the battery charge level gets a bit too high. It hasn't today, currently 45% and the house is using about 5% per hour, so I will be letting the usual charge to 60% on cheap rate go through. Maybe we'll get some more sun tomorrow...