question

TTbb avatar image

DC consumption not logging on VRM?

I have just set up a Raspberry Pi running Venus OS

System: 2x 75/15s + Pi / 7s Lithium NMC / DC only setup with all loads via the load outputs.

So the VRM dashboard shows 'live' consumption at last update, the advanced widget 'System Overview - DC system' does a good job of allowing me to see watts used at any point in time.

Load out data from the MPPTs clearly exists. Why then is there no DC consumption logged on the dashboard like solar power produced?

https://vrm.victronenergy.com/installation/50299/share/e844d84d


Venus OSRaspberry Pivrm remote consoledc system
10 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

1 Answer
Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi @TTbb

there is, but not as 'DC power' that is only available with a battery monitor.


8 comments Share
10 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Hi @Daniël thank you for the reply . I am not so interested monitoring the individual outputs at any point in time, although its useful and nice. Totals over a time period in watts is what i am after.

If all the data is already available and clearly it is because consumed watts are logged within the controller history, live consumed watts are being shown in the VRM dashboard. 'System Overview - DC system' can be used to track back what was used at any point in time. Why is a battery monitor needed just to log this data to present it like the PV watts generated? That seems to make no logical sense!

I thought i would give the VRM a go and set up the Pi because the MPPTs are functionally compromised by the lack of an internal clock. Without a new day starting at a consistent set time and a useful time such as midnight the logging in history is not really that useful.

Hi TT. I don't know if this is what you want, but if you set Dashboard to 'Last 7 Days' and hover over the bar you want, you'll get daily summaries.

Hi @JohnC yes that is exactly what i am after and it works wonderfully for solar but the issue is consumption is not logged. :(


@Daniëlis suggesting it can only be done with a battery monitor. As is probably clear form my response I can't quite wrap my head around that one. The data already exists form the MPPTs and is presented in 'advanced' where it can be tracked back. To show on the graph would surely just be taking the total between two points in time, what am i missing? Maybe i am missing something but is that not exactly what is happening with the solar logging??



In the VRM Dashboard, have you tried all selections in the System Overview box?

If you have 'Has DC System' checked in Venus, try with it unchecked.


When Has DC System is on live consumption is shown under system status but not logged. when it is off it does not show. The whole DC power logging seems a mess form what i can see.

@Daniël is contradicted by the victron VRM faq

"The calculated value for 'DC Power' is not used in any way by the GX, beyond just being displayed 'on screen'. In particular it is not logged on the VRM portal and it is not included in system calculation and it does not appear as part of the recorded Solar Yield."

That is saying it cant log at all evern with a battery monitor. but then @Markus writes something in an earlier post that contradicts that.

" I have read the requirements and I am a little confused. What does "Currently the calculated value for 'DC Power' is not used in any way by the GX, beyond just being displayed 'on screen'. In particular it is not logged on the VRM portal" mean? When I have DC consumption, which I have most, it is displayed and logged in the VRM graphs."

So maybe markus can give more clarity on what makes it work / what is required.

I wish I could test this for you, but don't have suitable kit on hand.

When 'Has DC System' is checked, the system expects to see a BMV to measure it and include as one of the data inputs. With no BMV, it will "calculate" it, usually from the difference between mppt input and inverter output. That 'calculated' figure is often a little 'unstable' due to varying sample times and other things. So that is likely what the literature is referencing. Not much point in using it for further analysis because it's a made-up figure anyway.

In your case, the mppt must know the difference between it's total solar output and what it's delivering to the batts, and the 'DC system' is calculating it rather than it coming directly from Load output measurements. If you compare the headings on Daniel's and your widgets, you'll see the different sources stated clearly.

It's why I suggested turning off that 'DC System' tile and watching the Consumption tab on Dashboard. Might need some time to gather enough data to see how that works though.

Show more comments

@TTbb Hi,

DC consumption on VRM overview graph, is only available when using a BMV battery monitor.

Regards,

Markus