As I understand it, the System PV yield is calculated by summing the two PV yield graphs of my MPPT and Fronius. Here you can see only the System PV yield is being subsampled, while the other two graphs show data from every minute.
Up to a week ago, if I set the quick range to 6 hours, I saw 1 minute updates on every graph.
Now, only the following graphs have dumbed down the display to every 5.5 minutes:
System: AC consumption
System: Grid
System: PV yield
System: Battery power
I had a closer look now - when you select a three hour period, it shows every sample. The System samples are now averaged over 5 minutes. All other devices still sample every minute.
From my perspective it looks like this averaging happens on the Venus device, but I might be wrong:
The VRM back end could be averaging 5 samples into one on their transactional DB. If this is the case, they are trading off: making the DB average every 5 samples in order to send less data to the end user.
When selecting a 6 hour period, the front-end graph code now subsamples to 7.5 minutes (only the System graphs), and that is why the graph changes, and shows subsampling averages and weird time indicators.
About 2 years ago I kept my graphs on 12 hours, and it showed 1 min updates everywhere. That was glorious.
Maybe many users only add system graphs, and subsampling only the system graphs saves a lot of bandwidth being sent to end users.
Another suggestion: Make this a free page for end clients, if you are okay with 5min or 10min samples, and a paid page for 1min samples? This setting can be sent from the back end to the device, so the end user can’t change the setting anymore.
I would pay for 1min samples… And then the registered Victron support guys, who need to see much more detail, can see 1min samples of all their clients free. All other, non-paying clients can see subsampled graphs.
Subnote: The details in these graphs motivated me to upgrade my batteries from 12.5kwh to 20kwh. It allowed me to calculate how much energy I was not getting back from the batteries in the morning after they ran out, and calculating how much solar energy I was wasting by not storing it in the batteries. Also: how much more panels to set up to allow me to charge a PHEV. It also motivated me to get the Viktron EV charging station, as this allows me to see when the car starts charging and how fast.
I am curious why you installed a Victron EV charger? Didn’t your EV come with a charger?
I have no issue with the Victron charger - just thought that most EV owners installed their car manufacturer’s recommended charger.
I suspect it has to do with the amount of data they need to handle on their side for all users internationally.
I read, and I could be wrong, it is an AI doing the prediction.
I suspect, in due course, it will become more and more accurate taking the weather prediction, expected solar irradiation vs actual production into account as the AI learns how to predict better on the predictions.
Expected cloud cover vs actual cloud cover … tough one.
There’s a blog post about it somewhere on Victron’s site, but they make use of Solcast and based on your installation’s location it gets the irradiance data from Solcast which I believe is what is shown in that graph.
Solcast does (try) account for cloud cover.
Edit: Yes, that graph is the underlying data from Solcast (link below):
In addition to the dashboard estimate, we also have the underlying Solar Irradiance Forecast (W/m²) available as a new advanced VRM widget.
Pretty much the above. Victron gets the solar irradiance figures from Solcast (forecast and actual) and uses AI modelling to compare that with what you’ve generated (in kWh) to get an idea of how your production will look like depending on the irradiation. That then gets more accurate over time so that a single in and out of clouds day doesn’t impact your ‘normal’ days as much. At least that’s my understanding.
Edit: Pretty much summed up:
We have created a machine learning model that compares historical solar production and the irradiance at the time of day and then calculates the future projected solar production based on the estimated irradiance forecast.
This automatically takes into account factors like system sizing, panel orientation & pitch, efficiency degradation, and shading without requiring any user input.
This means that over time the model will get more accurate, even as panels degrade and trees grow.
The model goes even further, accounting for when MPPT trackers were at maximum production, or limiting themselves (for example when batteries are full in an off-grid system).
I’ve been using Solcast for about 18 months and like any forecast the longer term is less accurate (they indicate a 90/10 probability). They used to allow sites to upload their actual data but I don’t they they allow this anymore. At least not on the free version.
Plonkster is correct, the Volvo came with a single phase 8amp wallplug cable.
You can get a Volvo wall charger but it is meant for two phase and can charge up to 7200w, or single phase at 3600w. Current limiting is only available through direct bluetooth to the wall unit. No current limit available in the Volvo car app. No integration with Viktron.
Price: the wall unit plus Volvo cable is almost as much as a Viktron EV station plus third party type 2 cable. If you live in a civilised country with three phase to your house, and cheaper electricity at night, the Volvo kit makes sense.
The Viktron EV station integrates with the Venus controller and only uses excess solar energy. It only starts charging when the main battery is at a preset level (mine is 50%), and there is enough current available to charge the car without drawing current from the main battery.
From there it monitors available solar energy - if the panels deliver too little and the energy is drawn from the main battery it decreases the charging current down to 6amp, and then gradually increases it again as the panels ramp up, in 1 amp steps.
Granted, I am only using single phase of the Victron EV station. So I am limited to 3600w, but this is all from the sun, and I can charge right through loadshedding at 3600w. It is connected to the output of my Multiplus 5000, and mainly fed from the new Fronius 5kw, also on the output.
If you already have a two or three phase Viktron system this will make more sense.
I know I over invested in the system to charge the car… but… this is kinda my pet project… and I’ve done 1200 km since new, on the first tank, with about a quarter tank left (included 400km farm trip). I expect to get to about 2000 km on my first tank of fuel.
Same for me. I think the i3 will allow going up to 7kW on single phase, but I wired mine with 2.5mm^2 cable so I’m limited to 20A, and I have it wired to a wall socket at the moment, which limits it to 16A. That’s 3.6kW, and ample for me. Much better than the car’s “granny charger” cable that tops out just above 2.5kW. Plus it has that control aspect. Which to me is somewhat useless: the car is away from home, the wife drives it to work when the sun shines.
But also, it records the energy for each charge session, and the total energy. And soon… if I get my arse into gear… we may even have “PV to EV, battery to EV, grid to EV” charts. That will be nice.
Right now I don’t want to. My site is a mess. I installed a Multi-RS, and it has no grid meter support (yet). So nothing is running optimally here. The limiter for the PV-inverter is also broken and if I forget to start the pool pump in time, the power goes into the grid and I pay for it
I’m a little ashamed of the shambles things are in… but maybe later, when it is all neat and tidy again
I have never done public charging. My car does have the DC charging option, but so far I have not used it. The last time I plugged it into a public charger, was after the last test drive. I parked it in front of the BMW dealer at century city, and plugged it into the charger. It was load shedding so nothing happened. The end.
There is a charger just outside Stellenbosch (James Town) that I will probably try some day.
