Grid zero point with Virtuel Devices behaves strangely

Node-RED
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1

Hello, since last year I have been running my three-phase Victron system with three MultiPluses and a battery storage system. My existing balcony power plant is also running in parallel.

Based on the weather forecast and my own estimate of consumption, I set the grid setpoint to zero. This initially works quite well. The actual value fluctuates within a relatively small range around this setpoint.

This spring, I integrated my BKW into the VRM via Virtual Devices in Node-RED.

Since then, I have been experiencing the following problem. On the one hand, the range within which the value fluctuates around the zero point has become somewhat larger. The bigger problem is that while the BKW is supplying power, the grid setpoint deviates upwards from the configured value by around 80 watts.

As a workaround, I simply set the grid setpoint 80 watts lower from sunrise to sunset, which keeps me roughly where I want to be.

What puzzles me, however, is that it worked correctly before the VRM integration, even though the BKW was already running in parallel before that.

Perhaps this is a bug that has not been identified yet. Maybe other users have had similar experiences.

A friend of mine, who has a system with three MultiRS units, is seeing something similar in terms of the range around the zero point. However, the position of the zero point itself is not shifted.

That’s all for now.

noltkaemper

2

VRM is simply a reporting portal. It allows some manual, remote controls back to the system but it cannot influence a running system on its own. If you are running DESS, then that is a different scenario.

Virtual devices have limited capabilities, the use of this functionality is also not strictly supported as it may not behave as expected. There are limitations that apply.

It is not an exact science. You are introducing a new variable into the system which is trying to compensate, the accuracy of which may vary depending on how it is integrated.

A pure zero point grid setpoint is theoretically possible, in reality it is just a point the system will try hit as an average. There will be fluctuations around this point for many reasons - lots of topics on this exists already - the more customisations you use, the less likely it is to be consistent.