Forecasts data source

Hi all,

I’m one the happy owners of a Multiplus ii system since a week and have a question about the forecasts. I have ESS enabled and was wondering where the solar and consumption forecasts are coming from. Is this only historical data? And if so is it as easy as looking at the historical consumption per hour and take the average of that? So let’s say last 4 days I’ve consumed 1,5 kwh between 1700 and 1800 hours? Or is the average per hour looking at the whole day?

Looking at the solar forecast it is more then just the history and it looks it is taken weather forecast also into consideration. If so which source data does it use for that?

The reason for these questions is that in 1.5 months I’m going to use DESS and since this is way more depending on forecasts and the current forecasts are way off…..

Update 10-8-2025. Here is today`s forecast, way to low but ok. We already see that between 8 and 9 AM I harvest 3 times the amount of energy than was forecasted. For now this is all fine but when DESS comes into play, I’m a bit worried…

And here is a screenshot where the consumption prediction is show..also strange…same consumption each hour…

It takes a couple of weeks to get a good forecast. My ESS is running for a while and forecasts very accurate.

1 Like

Vrm has also had a problematic week which has affected forecasts as well.

Hmm ok…so it takes a couple of weeks to settle. Then let’s wait and see what will happen. I did search the forum and have seen quite some posts about forecasts but very few answers from Victron or a Victron representative. Although they encourage to go to the forum to report issues the engagement does not look very high…

My questions did got answered so I satisfied :sweat_smile: