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martinwinlow avatar image
martinwinlow asked

MultiPlus II - Built-in Octopus Agile Configuaration?

Is there a built-in programable feature of the MPII that will permit it to automatically switch on the inverter at 1600 hours (thereby disconnecting the mains) and on again at 1900 to permit charging thereby avoiding the expensive tariff between those hours? I was going to just use a plug-in mains timer to power a large contactor to isolate the mains connection to the MPII in which case the MPII would just take over the house's mains supply (powerng it from my 20kW battery) as if there had been a mains failure...
Regards, MW.

Multiplus-II
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owen-a avatar image owen-a commented ·
I'd like to add that I recently installed a Victron Multiplus 2 (3kva 24v) for my on/off grid outhouse in my garden. It exports to the grid when there's excess energy from the solar panels (DNO approved that I submitted by myself), and between 1600 and 1900 I have it setup to export at least 250W from my 100Ah battery bank IF the panels are generating less than 200W.


I'm using Octopus Agile myself. With Home Assistant (which is something you can install on a raspberry pi like I did) there is an Octopus Add-on you can install so you can get all the stats from your Octopus account (including real time usage if you have the Octopus Mini). From this, you can create automations to do anything.

The Victron Multiplus has MQTT support that you can enable via the Cerbo GX, and there is an Add-on for home assistant that allows the Multiplus to talk to Home Assistant sharing all of its stats and configurable entities.

From this I was able to create an automation to do what I mentioned above. That's the simplest approach that doesn't involve any knowledge on working with API's (although I am a software engineer, Home Assistant is very powerful and keeps things simple).

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Jason - UK avatar image
Jason - UK answered ·

@martinwinlow In short, there is no easy solution.

Firstly, what Multiplus II do you have and what batteries? 5kva MPII? Also, what is your average peak load and your incidental peak load? You'd be better keep with an ESS mode of use, so the grid maintains the house voltage and the MPII just balances the loads, that way if you have a sudden high load, it doesn't overload the Multiplus causing a MPII shutdown and the MPII will have a greater life span.

If you want a MPII to work with the Agile tariff, you would be better off using Node Red to control your Multiplus II via either the IFTTT service or via the Octopus Agile API, that way you can dynamically charge and discharge your batteries.

I have a Multiplus II 5kva GX unit doing nearly my total house loads inc heating and hot water via a ASHP but for 1-2% of the year I go over the 5kva output of the Multiplus, the gird for the short period makes up the difference by using ESS.

I'm in the slow process over changing my house energy controls to work with the Agile tariff whilst I sit on the Octopus GO tariff. The heating is controlled by Heatmiser Neostat V2's but I'm yet to find a dynamic way of charging the MPII with my test Node Red controller.

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martinwinlow avatar image
martinwinlow answered ·

I'm afraid I am an avid experimenter and am very much in the process of working out a sustainable (in energy and financial terms) system of providing power and heat for my 1850, stone-built semi in the wilds of the Hebrides. As a gude, my annual electricty bill was £3k5 so, pleanty of scope for fast payback improvements.

I'm hoping that once I have settled on a workable system, it can be replicated for other homes here.

The house has damp 600mm thick stone walls, cementitiously rendered externally and is relatively poorly insulated with little scope to easily improve it. All bar one of the windows are horrid 70's (?) aluminium framed double-glazed affairs but all these (and the one remaining original wooden sash window) are due to be replaced imminently with triple-glazed ones (make yet to be determined). I suspect this will have a far more dramatic effect on heating requirement - in terms of bang-for-buck - than improving the wall insulation. The question of then providing adequate ventilation (ideally whole-house with heat recovery which I have done before in a different building) is also foremost in my mind/plans.

I installed a £600 'easy-fit' one room split heatpump last year which has made a huge difference (on its own it will save about £1kpa just heating my study where I spend most of the day if I am in) but not a particularly easy job with the 2' thick stone walls to contend with.

As it turns out I ended up on the Octopus Flexible tariff - there is an as yet unresolved issue around switching my 2 meters over to one that lends itself to making the most of Octopus (a smart one I guess) as I have an old fashioned setup that uses a 'Total Heat Control' meter (that comes on at various times throughout each day/night at the whim of the old provider SSE/Ovo) as well as a very basic 'day rate' meter. The former does all the heating/hot water via a separate consumer unit (all electric, mostly "ultra-efficient!!" (yeah, right - thermally, yes; financially NO - how do they get away with it?) panel heaters and 2 very old night storage heaters - one just replaced with a new Dimplex Quantum QM050RF, the latter meter does everything else (including the garage and therefore EV charging via a second consumer unit).

I currently have two 5kW Multiplus-IIs in parallel and the way I see it, the easiest/best (probably not best but easy = cheap) is to have a basic tariff (Flexible would work with its 15p/unit night rate, day rate twice that - compared to my old Ovo day rate of 32p/unit and 27p/u THC rate) and just turn off the mains at 0700GMT and let the Multiplus-IIs and ~20kWh battery power the house until midnight.

I have no knowledge or experience of IFTTT service or Octopus Agile API (both of which sound like they come with a very step learning curve) and given that I suspect Octopus is going to be *very* reluctant to send someone all the way out here to swap my meters for a smart one (at least any time soon), I really want to try to keep things straight-forward. I may even end up paying to get a smart meter 'privately' - if indeed that is possible... I am a bit puzzled that Octopus have not identified the meter issue already themselves as I told them all about it before I swapped over but that is a (no doubt tiresome) phone call I am intending to have very shortly...

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gazza avatar image gazza commented ·
Interesting story..! I am curious about your 'Total Heat Control' meter? I have never heard of that? Is it like Economy 7? How does the switching work? Sorry for all the questions but I have a vested interest. I have a Flexible Octopus tariff using Economy 7 with RTS switch... The catch is that this switch is controlled by a LF radio signal from BBC Droitwich (.. seriously). Next year this is going to be switched off, so, without a smart meter, even Economy 7 wont be available, never mind any other Octopus smart tariff.! :)
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Jason - UK avatar image Jason - UK commented ·

@martinwinlow I have only the one 5kva unit which covers most of my energy demands apart from when my better half has the oven and hob on as that is 4.4kW with both on (one oven, one hob) but during the heating season, I'll be pulling 7.9kW around dinner time so I have adjusted my heating to not run when dinner is normally being cooked.

I have a 1960's 5 bed detached house which previously had a 3k gas bill before covid. I, like yourself like to engineer solutions but I'm lucky to have a smart meter in that respect. I have whole house ventilation with heat recovery, as well as a 5.7kW PV array, 4 x Tesla Model S batteries, a ASHP what just about heats the whole house in the winter and the Victron Multiplus II GX making it all work together.

Below is a link to my VRM portal, of which in the photos section is my schematic. If I had your house, I would use a IFTTT enabled time clock (Heatmiser Neostat HW? with Neohub?) linked to the Octopus Agile IFTTT service, switching when the rate is below £x and switching again when above £x. That switching could be set up to connect and disconnect the Multiplus from the grid. "no 5kva units should be enough power for any household. IFTTs is easy as all the 'comments' are already set up for you, you just have to select 'If this', then that.

https://vrm.victronenergy.com/installation/171934/share/db6807bb

https://ifttt.com/explore

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martinwinlow avatar image martinwinlow Jason - UK commented ·
Thank you - I'll see how tomorrow's Octopus call goes and I can go from there. I've done a fair amount of VisualBasic programming in the past so I'm just being lazy with IFTT...

Thanks for the links.
I hope your hob is induction...?
I assume you mean 4 x Tesla battery *modules* (ie not 4 x full packs...)?

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Jason - UK avatar image Jason - UK Jason - UK commented ·
@martinwinlow yes, I have an induction hob. Yes also on the Tesla modules.

Node Red isnt that hard either, more so because you can run a test set up with no risk.

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Jason - UK avatar image
Jason - UK answered ·

@martinwinlow I have only just last night found out there is a post regarding dynamic ESS already available within the Beta VRM portal. All the info is on the below links, but in short, for UK users, fixed off-peak import & peak export times are supported taking into account expected solar generation. If you want dynamic pricing, you have to use a Node Red controller still within the UK as mainland Europe is only currently supported directly within Beta VRM.

I'll be downloading the Node Red and installing onto a Raspberry Pi this week to give it a go as I had been developing my own Node Red control but now I don't have to.

Dynamic ESS on Beta VRM - Victron Community (victronenergy.com)

https://youtu.be/YU9jXyfM-eI?si=B56-boiDqbk8CtWM

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martinwinlow avatar image
martinwinlow answered ·

Hi,

Between my chat with (very sensible) Octopus and the fact that the whole country has now apparently lost it's radio-controlled meter timings I discovered that (somewhat to my surprise) that the THTC meter I have here is no longer supported and so my electricity bill now only has a day rate (from the day meter) and a night rate from what was the THTC meter (which is now behaves just like a basic Eco7 meter... or Eco something - I did not get to find out exactly what timings are involved as at the time of the chat I thought the radio control was still going on).

Would it not now make sense for me to now rewire my consumer units (both 'day' rate and 'night rate') so that they are both fed off the the night rate meter only, assuming the night rate timings are sufficiently consistent in their ons and offs so I can program whatever load bypasses the Multiplus-II during the off-peak times to use mains directly eg EV charging, battery energy store charging and night storage heaters (only have a small one left in the kitchen)? It gets ever more complex!

Octopus did at east confirm that I can have a smart meter only it will be a 'dumb' one for now as the required radio system doesn't work up here yet. Also they say the meter install itself is free but not the transport out to the island plus a minimum of 2 nights accommodation (only 4 ferries a week in winter, here). So the smart meter will just behave like a basic Eco7 (or whatever) meter until the smart bit is turned on. Why don't they just use 4G, FCOL?

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Jason - UK avatar image Jason - UK commented ·

@martinwinlow Octopus are trialling the use of Lofi, and Wifi for sending meter readings. Currently they have to pay a fee to a network for receiving the data from smart meters which gets added to everyone's bills (smart or not smart) within their standing charge. If they can use the Wifi thats within nearly every household now or LoFI for houses with remote meters, it will save money which in turn will benefit the consumer. Watch this space I guess, but if it does become an option, your smart meter will be smart with or without any network connectivity. The Octopus Home Mini comes within the same means of meter reading. See if you can get one and use that with your meter.

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slartybart avatar image slartybart Jason - UK commented ·
Another vote for the Octopus Mini. It basically does what the smart meters should have been doing all along.


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