BUG: (D)ESS limits 3ph grid power based on 1ph current limit at energy meter

Q&A and troubleshooting DESS
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1

Actually a straightforward question / issue since I had the same with a multiplus (see this topic), which was quickly resolved by Victron.

Recently I did a standalone Multi RS Solar install in a 3phase grid and this suffers from the same issue. Basically (D)ESS does not allow the 3 phase grid power to exceed single phase power limit “UL1 * configured current limit at grid meter”.

I don’t know how to get this under the attention of the developers, therefore opening a new topic.

Setup :

  • 3phase grid (3x25 A)
  • Cerbo GX
  • Multi RS Solar on L1 with AC-IN limit set to 25 A
  • 3 phase EV charging station on AC- IN
  • (D)ESS enab led
  • VM-3P75CT grid meter, configured with 25A current l imit
  • Multiphase regulation enabled
  • Venus OS 3. 80~33

Sit uation

  • EV charging with 3 ph 11kW
  • DESS is active, EV forecast for specific hours set to 11kWh
  • DESS indicates it will get all power from the grid / solar. It even wants to charge battery a bit
  • Expected behavior: DESS will get power from the grid and solar to power EV and charge battery (as per schedule)
  • Actual behavior: Multi RS discharges 2620W to keep the total grid power at ~5962W (25A*240V)

Above is not DESS related since it also limits the AC power when ESS with an AC setpoint of 11kW is used. Behavior exactly the same as linked topic.

To work around this issue I can configure a grid current limit of 75A. Then everything works fine, but I don’t have the peakshaving anymore. If the PV drops and DESS decides to charge the batteries with 4000W there will be an overload on the AC L1 fuse.

I hope someone of Victron can bring this under the attention of the developers. Last time it took only a day to fix it, so it should not be too complicated.

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2

@iburger sorry to tag you directly, but since you fixed the issue for the Multiplus I am wondering if you can take a look at this for the Multi RS also? :folded_hands:

3

Recently some updates on Venus OS and Multi RS solar firmwares have been released. Above issue is still present in Multi RS v1.31 and Venus OS v3.80~42. Also tried the “single phase” (instead of standalone) configuration item in Victron Connect for the Multi RS Solar, but this eliminates the multi-phase regulation all together.

I am not sure if the recently released Multi RS invert is having this bug also, but Victron needs to fix this. Either DESS is unusable with single RS in 3phase grid setup or it will blow your fuse when grid meter current is increased.

@jeroen Zou jij hier kunnen helpen? :folded_hands: Dezelfde bug voor de multiplus is dankzij jouw hulp ook snel gefixt.

4

Your EVCS is configured on your AC-out; shouldn’t it be on the AC-in side? Given the power of your EVCS, you’re charging with three-phase, since the maximum over a single phase would be 32 A, which comes to approximately 7,680 watts.

I don’t know whether this is the solution to your problem, but perhaps switching it to AC-in will help.

5

The EVCS is indeed visualised on the wrong side (although Virtual EVCS is set to AC-IN). However, this is not the cause. If I use more than ~6 kW across the three phases with any kind of load (e.g. hob + washing machine + oven), the Multi RS starts peak shaving. If this occurs at a time when DESS has decided to charge from the grid, that does not happen. In fact, the battery discharges instead of following DESS’s strategy.