DESS Trade mode prioritizing grid-to-battery over PV

Q&A and troubleshooting DESS
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1

Hi all,

I’m running a 3-phase setup with a Multi RS Solar 48/6000, controlled by a Cerbo GX. I have several PV strings connected directly to the Multi RS (DC-coupled), and I’m using DESS trade mode.

Overall, the system works very well. It manages energy flows quite intelligently — charging the battery from the grid during low prices and discharging/exporting during high prices.

However, I’ve noticed something that doesn’t seem optimal: my PV production is being limited, even when more solar power is available, while at the same time grid-to-battery charging is active. This makes it appear that grid charging is being prioritized over PV charging.

From a logical perspective, I would expect the following priority in energy flows:

  1. PV should first cover local consumption

  2. Any excess PV should go to charging the battery

  3. Grid energy should only be used to supplement this, charging the battery up to the configured maximum grid import and battery charge limits

Since PV energy is essentially free, it seems inefficient to limit PV while importing energy from the grid to charge the battery. In my view, the only exception would be during negative energy prices, where it makes sense to prioritize grid charging and potentially limit PV production.

My questions:

  • Is this behavior expected in DESS trade mode?

  • Is there a way to influence this priority without using complex Node RED settings?

  • Or is this a known limitation that might be improved in a future update?

Curious to hear if others have seen the same behavior or have found ways to optimize this.

In the images below, an example is shown of PV output being limited, starting exactly at 12:00 when grid-to-battery charging begins.

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Thanks!

2

Hi, welcome.
I moved this to the right section.
Suggest you have a read of the existing topics, likely this already exists in various related topics that may, or may not help.

3

I’d say it is unexpected, but could have to do with some non-optimal configuration. But it is a bit hard to tell with just this info. Would you be so kind to provide your vrm id (the number in the url)?

4

Of course, the VRM id is: 756158

5

Just learned that this isn’t Dynamic ESS doing this, but the underlying firmware of the Multi struggling to keep the PV fully coming in while it is also pulls from the grid at max speed.
What doesn’t help is that you configured your battery that it can (dis)charge at 45 kW, while I haven’t seen it exceed 16 kW. This results in this scenario, where both the grid and the PV compete on getting the battery full, happening more often.
In the end it will be fixed in a newer Multi RS firmware. But you can already reduce the chances of this happening on your system so frequently by setting the Maximum charge power lower. As you battery can do about 16 kW, configure it to 15 kW, leaving some room for you PV to top that up.

6

Thanks! I’m going to try the 15kW limitation for the battery,