Oh, my mistake, I missed your post, but it is exactly the same problem, so the implementation is obviously not correct. Also I think, that behavior of Trade mode in case of negative prices is not correct for that reason, because if price became negative, the goal should be cover consumption and also charge the battery from grid, not from PV (I can imagine this in Green mode, but not in Trade mode).
I am using DESS in Trade mode, because I want to feed-in PV energy directly to grid in case of higher positive price (especially in the morning) and after that when price drops use PV to charge the batteries. Second benefit should be to use as much energy from grid as possible in case of negative price to get better final energy bill (obviously :–) ), to help stabilize the grid (when there is a lot of excess energy) and to not use PV (extend the life of solar panels and MPPTs).
I think there is an issue with the presentation of the numbers in VRM, but I’m not sure if anything is wrong with DESS itself. I don’t see strange behavior with negative prices myself. That your PV is used to charge the battery when prices are negative is not necessarily incorrect, the PV energy has to go somewhere.
No, in this case PV power was not used to charge the batteries, but to cover the consumption, which is in my opinion wrong behavior in case of negative price. Better behavior is to use grid and don’t use PV (for reasons I wrote - grid stabilization, extending lifetime of MPPTs/solar panels and better energy bill which should be the goal of Trade mode). Charging the batteries was done in next hour also with help of PV power.
What do you mean by “don’t use PV”? If you don’t want to use PV when the price is negative, you should switch it off, otherwise the energy is being produced and it needs to go somewhere: consumption, battery or grid.
For my opinion, it is not necessary to use PV all the time if it is available, especially if there is better/cheaper source at the same time = grid in case of negative price. DESS should use as much energy as possible from the grid and automatically limit power from MPPTs (if the consumption is over the set grid limit, PV could be for example also used to charge the batteries), which is probably what you are doing in the Node-RED, isn’t it?
Yes, I have SolarEdge AC-coupled PV, connected via Modbus/TCP, which DESS is not (yet?) able to limit, so I’ve created a node-red flow for that. If you have MPPTs from Victron, they could/should indeed be reduced in power by DESS.
Yes, this should be reduced with Victron MPPTs, but the reality is different… 
I also made a lot of another automations in Victron system by Node-RED, so probably I will have to do also something about this 
Thank you Victron staff for fixing wrong calculation in VRM!
And what about the second thing about using power from PV instead of using power from grid in case of negative price? Is it something which should be already implemented in Trade mode of the DESS or it could be something to add on To-do list? 
Today during negative grid prices same very bad behavior of DESS. I have implemented in Node-RED switching off all MPPTs in case of negative prices, but DESS still use battery instead of grid.
Why? Why DESS uses PV or battery instead of using grid when price is negative? This completely makes no sense, especially in Trade mode…
Victron team, please take a look at it and change/fix this wrong behavior.
Hi there,
Unfortunate that on days with negative prices, Dynamic ESS does something you don’t expect it to. Could you share your installation url, so I can ask someone on the team to take a look for you?
Kind regards,
Barbara
Hello @Barbara,
thank you for your effort.
DESS has information about negative price and the goal in Trade mode should be final bill as low as possible, so using PV or battery instead of grid during negative price does not meet this goal completely…
I will try (in addition to switch off the MPPTs) also change battery mode from Optimised to Keep batteries charged during negative price, which should help to achieve correct behavior, but DESS algorithm should have implemented using grid during negative price.
My installation ID is 152686, but I expect negative prices no earlier than Sunday, yesterday were negative prices due to Labor Day.
Hi @Barbara, I have the same questions.
Tomorrow the price will be negative for three hours in the Netherlands.
My system is three Multi RS’S with Cerbo.
Id: 356542
It looks like DESS will stop using energy from the PV in the third hour (when the batteries re full). But in my opinion it should not use PV power from the Multi RS’S all three hours, and charge from grid only when prices are negative.
And the system acted exactly like in the pictures. The first two hours with negative prices the battery was charged with power from PV an grid. In the third hour, when the battery was charged to 100%, the PV production went down, and it went up again when the grid price was positive again. Why not stop the PV power all three hours with negative prices?
Not only for better financial gain. But also to improve grid stability. That way our battery uses pv-power from our neighbours.
Today, a few days after the day with three hours of negative prices (where pv Power was used to charge the battery), I see that the system is throttling down the PV production in the cheapest (but NOT negative) hour of the day, to charge the battery from the grid. In my opinion, PV production is always cheaper to charge the battery, than buying from the grid as long as the price from grid is not negative.
There is still room for improvement.
For me it’s the first time tomorrow with DESS facing negative hourly prices.
I’m running green mode and would expect it to charge with max power during that time.
But the DESS schedule says: consume from battery!!! (SoC is not reaching 100% according to VRM forecast so there is plenty of headroom for charging from grid with negative price!!!)
PV and battery are 100% AC-coupled, no DC-DC MPPT involved. My installation is VRM Portal - Victron Energy
Also in preparation for tomorrow, DESS could have throttled charging today to reserve more battery capacity 
As a workaround I just created an automation in Homeassistant which will push grid set point to +20kW when price is lower than -0,01EUR/kWh
We are encountering two problems with the current setup involving Victron SmartSolar and Fronius in combination with dynamic energy pricing.
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Solar Behavior at Maximum SOC:
When the battery reaches its maximum state of charge (SOC), the system correctly switches the solar production to self-consumption only when electricity prices become negative. However, even during negative pricing periods, the solar production is not being curtailed or turned off as expected. This results in excess energy being generated without economic benefit. -
DESS Timing and Minimum SOC:
The Dynamic ESS control starts selling energy too late. Because of this delayed reaction, the battery does not sufficiently discharge to the intended minimum SOC target. For example, today the minimum SOC was configured to 15%, but the system only discharged down to 40%. As a consequence, large parts of the day the solar installation had to limit or completely stop production, since the batteries remained too full.
407704
My observations from May 11th 2025
Negative prices occurred between 12:00 and 15:00. Charging started correctly at 12:00, but continued until 16:00, with a short pause around 14:00. As a result, the cheapest hours were not fully utilized. Charging continued even after 15:00, when the price was already positive.
Around 14:00, I manually activated 23 kW of additional load. Instead of drawing this power from the grid (which would have earned money), most of it came from the battery. This feels like a missed opportunity.
It would be great if solar production could be halted during these negative price hours.
VRM Site ID; 356642
Hey, @Barbara, pinging to check in after a little while since this was last discussed – it seems to be an ongoing issue for multiple users, and I’d love to have a bit more clarity from Victron on what we should expect from DESS in this space. There’s clearly some room to optimise DESS behaviour to make best use of the favourable grid pricing at times 
Pinging @Barbara and @dognose – I’m not sure who has lead on this feature – but today was another good example of DESS not behaving in an optimal way with negative prices. As before, VRM installation ID 510670, 25/06/2025 AEDT for your reference.
Between 1130-1200 and 1230-1430, buy and sell prices were negative in my part of the world, and DESS knows about those prices (see here) but didn’t make best use of that opportunity.
Running in trade mode, I would expect DESS to run all loads from the grid and maximise charging to the batteries, as we are being paid to use electricity. Instead, DESS continued to first use all the available solar, then top up the batteries at a lower rate of charge (presumably to reach the target SoC for that period of the schedule) from the grid. My environment has two Multiplus II 48/5000s in parallel, giving me a theoretical maximum DC charge rate of ~140A – what we saw was a charge rate of mostly around the ~80-90A and little “peaks” to ~120A throughout the day:
I have worked on the assumption that the system’s charge theoretical max charge capacity is reduced by any AC loads the inverter is supplying (in this case, there is ~1000W of AC-OUT load, even though we’re on-grid at this point).
If DESS was in green mode, I could accept this behaviour: in the pursuit of “green-ness”, prioritising a low-carbon energy source over a potentially higher-carbon energy source might be acceptable (though, paradoxically, when the price is low or negative in my part of the world, it is due to an oversupply of renewables!). But the behaviour of not maximising profitability (or even maximising charge rate) when prices are negative doesn’t make any sense.
Would love to hear from Victron staff if this is expected behaviour and indeed help with any testing moving forward.
Currently VRM/DESS only has the option to restrict Feedin during times of negative prices.
That means, whenever you would like to “pull from grid” during negative prices, Solar would need to be shutdown completely - which DESS cannot do at the moment, as the solar charger and their throttling is controlled by the underlaying ESS-System and that will always “unthrottle” as much as required to drive the loads, when feedin is restricted.
Improvements are beeing worked on, but due to the complexity of touching kinda “root-mechanics”, an estimate cannot be given.
As for the low chargerate: DESS Schedule + local system requested a chargerate of 8000 Watts throughout the whole time. But your system didn’t do that. So, either you are running into overload-based throttling (heat) on your multis or there are other limiting factors such as a too low chargevoltage or any other limits (BMS, DVCC, PeakShaving, ACCurrentLimit) that took precedence?
See the yellow line, almost continuously requesting to charge with 8000 Watts, while your system goes up and down around 5000 Watts:
