Venus GX data modified on VRM?

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oropi asked Aug 3, '20

Venus GX data modified on VRM?

Hi, I installed a Venus GX to monitor a solar system, it works very well and I found the problem... the customer was sucking -80amps @ 50v (yes 4kw !) using the system to make tea and toast at the same time !

The system overloaded and shutdown (funny that !) so it was maybe only at 4kw for 10-15 seconds.

The strange thing is... a few hours later I logged in and the -80amps was clearly depicted on the V/A graph, clear as day and a pleasure to see.

But when I go back in to show the customer the logging, the particular -80amps plot is not there anymore, all of the days data is there, I am familiar with logging software I have triple checked the dates, times etc, I have stretched out the data to the hour that it was covered in, I have downloaded and reviewed the xls file,

But there are no xls timing gaps, there are no graphical gaps, it is like the software has 'smoothed' the 10-15 seconds of -80amps down to a more consistent -10amps for that time of the day.

How I wish I had taken a screenshot.... and now I'm even questioning did I really see it !

NB the shutdown was an Outback Inverter so there is no Victron error log, likewise no low battery alerts as none were set.

Appreciate any comments.

Venus OS

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Answer 1 · 2020-08-03T07:32:26Z

oropi answered · Aug 03, 2020 at 07:32 AM

For the future I have set some alert rules, being Discharge Current Low which I have set to -60 amps (minus 60 amps) and because it was mandatory I set the Discharge Current High Reset after reaching -40amps.

I also had to set a Discharge Current High (mandatory) so I set alert at +120amps which is above the solar capacity, so I shouldn't receive any high current alerts.

The next step is "Notify After " which I have set to 60 seconds, but does this mean notify me if the state remains at more than -60amps for over 60 seconds and also does not reach -40 amps within 60 seconds.

So in event of an 20 second Inverter (non Victron model) overload when it hits -60 amps and the inverter shuts down, and because the sun is shining the solar current rises to say +20 amps into the battery, do I not get an alert ?

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Answer 2 · 2020-08-03T08:16:13Z

oropi answered · Aug 03, 2020 at 08:16 AM

The more I look into it the more conundrums I see in trying to use using the Discharge Current Limit as an Inverter (Non Victron model) overload or shutdown alert.

For instance if the solar was producing 60+ amps and the inverter was overloaded with 80amps, then the net is -20amps for 20 seconds, before swinging to +60amps (solar input) which will not trigger a DCL alert.

So what using one of the Venus GX inputs as a state monitor ?

The inverter is on 24/7 and if the inverter shuts down a relay closes and puts a state change across one of the Venus inputs to register a state change on the appropriate widget ?

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Answer 3 · 2020-08-03T12:54:04Z

Teun Lassche answered · Aug 03, 2020 at 12:54 PM

@Oropi Lead VRM developer here.

We do not change the sent data in any way. We do keep the number of points in a graph limited, so if you look at a larger time range, the graph is smoothed a little. You can still look up any spike in the data by zooming in.

I just checked your specific case and when you zoom in around Sunday 2 August 2020 05:37:00 UTC, you clearly see the spike you mention:

screenshot-2020-08-03-at-145349.png (28.8 KiB)

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