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Not a question specific on DESS, but in my opinion the question is related to that.

Competitors are introducing battery systems that can trade on the energy imbalance market. Zonneplan is currently going to the market with this (https://www.zonneplan.nl/thuisbatterij) and Sessy is investigating the possibilities (https://www.sessy.nl/verdienmodellen-van-een-thuisbatterij/).

Is Victron Energy currently also investigation this business model for Victron System owners?

For example the Nexus generated Euro 20,41 on February 27th.

Update 05 March 2024:. Frank Energy will support trading on energy imbalance markets for a lot of Victron’s competitors. (https://www.frankenergie.nl/nl/slimme-diensten/slim-handelen).

Absolutely great! I'm particularly pleased that these two points are being implemented:

• Maximizing battery charge by the end of the day to cover consumption until sunrise.
• Periodically fully charge the battery to allow balancing

I will probably use DESS permanently as soon as these two, or at least the first of the two points, have actually been implemented! Thanks a lot!

I only notice two further things:

1. Grid set point is ignored when DESS is acitvated. However, I would always like to adjust slightly into the negative in order to avoid purchasing from the grid as much as possible:

I have tested values up to -150W: When DESS is deactivated, it is regulated to this value, but when DESS is activated, it is always regulated to setpoint 0W.

2. SOC-values are not shown correctly:

I still have some weird things in the ESS energy graphs on beta VRM:

fyi: In my settings I have disabled the possibility to charge the battery from the grid.

See the Grid to Battery (Orange) at 10-11h and 15-16h.:

Compare the to the graph below of the same time frame: nothing from the grid going to the battery:

I think the orange part in the DESS Energy graph should have been solar (DC solar in my case, which is forced by me by setting the inverter capacity to 0 - via Node-Red). I hope it is just a visual thing and not something messing-up the calculations

Great progress. Are there any details on how the alogrithm works within the hours slots to adjust to actual realtime PV and usage? Is it using a set-point? I did try looking in the documentaiton, but didn't see this described.

Do you plan to renew the Dynamic ESS promotion? It would be very welcome!

Great progress! I'm really looking forward to the next release.

Do the enhancements also account a heater like MyPV ACthor? Of course it is just a high load for the system but the operation usecase is slightly different than a EV or heat pump.

My understanding for EV or heat pump is that they produce the high load when they need it and the ESS just need to deal with it and bring this load into account.

The MyPV heater just steps in when everything is already served as the last high load to use only PV sureplus when it would flow into the grid. But it can be improved to use it with higher efficiency. When the DESS decides to use the grid to charge the battery because of low grid costs it could also feed the MyPV heater with a settable ratio of load sharing. It could be possible, depending on the gas/oil price, that heating the water is cheaper with grid energy. The gas/oil price is always a static contract fee. So calculating it is not that difficult, i guess.

But could be also possible that selling to grid out of PV makes more sense instead of feeding the MyPV heater.

Connected via Modbus TCP, VenusOS has the possiblity to bring that into account. At the moment it is a very simple thing. Every energy what would sold to the grid is going to the MyPV device. But that could be improved with DESS a lot.

At the moment, always if DESS decides to feed the grid this load will be consumed by the MyPV device. I think this produces problems because it is then counted as internal load. So DESS is not able to sell to the grid (when the water temperature is lower as the target value of the MyPV device). I think this situation is not good for the DESS alogrithm, DESS expect to feed in but internal load happens. But if VenusOS would be aware of the device it can be included.

I'm using it in that way: https://www.victronenergy.com/live/actor_ess

Also i really would like to see the MyPV device in VRM like an EV Charger.

After the beta11 update the system now seems to invert the hysteresis percentage back to grid right after it was charged ?

I have my min soc set to 45% and every single morning my DC PV starts charging the battery to 47% before the inverters kick-in to invert excess DC solar to grid. The 2% gained normally gets inverted at the highest price at the end of the day.

But this morning it seems to charge and invert a bit later. Is this related to the code changes for #2 ? At first glance this result seems highly inefficient due to chemical losses and battery costs.

<edit> it seems to have stopped discharging at 46% when the next schedule started and was set to 46%. will set inverter to 0 and see if forcing additional solar charge to battery will act the same at the end of a schedule.

I just noticed when i charge my EV from the grid at the time my battery is charged from PV it will show the grid consumption as grid=>battery. But that 6.29kWh was going to EV from the grid. My wallbox is behind the AC Out and i have the ev charger in vrm via dbus-mqtt.

It seems that Target SOC still has high priority and is not flexible when circumstances change. There is more sun then expected and PV brings 6000+ Watt. But target soc is reached and excess is sold to the grid. But at this moment the grid price is low. So I rather have this excess in my battery (even better my car but my Victron EV charger on auto does not want to start, but that is another challenge).
I presume this is unwanted?

DESS ignoring Active SOC limit (45%) set by Battery Life, causing charging from grid to battery the hour after.

From the DESS Energy graph, you can see the consumption (car charging) being fed from the battery and while doing so going through the bottom limit:

Whether it was smart to dump the battery at that time anyway, given the much higher prices a few hours later is questionable:

Hello,

something I noticed which is strange behaviour that DESS is start charging the battery from the grid if the solar forecast is not met. THis even happens to peak energy pricings. Anyway to stop this behaviour. from my perspective it would be much more beneficial if DESS is simply adjusting the battery usage for upcmoing forecasted demands rather than charing to highest prices just to be able to provide energy later to maybe even lower grid prices...

Best regards

Peter

v3.30~13

Still loading peak from the grid

DESS is really exciting. Once all the bugs have been fixed, it will be a really great thing.

Today I aborted another test (v3.30-13) because the behavior is inexplicable and illogical to me: instead of charging the battery as fully as possible with the first photovoltaic surplus, the battery should only be filled a little late in the day and discharged to a minimum SOC of 15% around midnight, as planned by DESS. According to the forecast, the charge level should then miraculously jump from 15% to around 50% after midnight and thus cover further demand during the night. Which miracle should fill the battery at midnight?

Why isn't the battery charged as fully as possible as early as possible during the day? The forecast with charging in the afternoon would also not have been possible due to changes in the weather. I canceled the DESS test in the morning and will now probably get through almost the entire night until sunrise and not just until midnight.

Am I doing anything wrong or dont I understand the logic behind DESS or is there a bug?

Kind regards.

I am seeking guidance to understand an issue with my Victron energy management system. I've observed that despite the electricity prices being negative, which should ideally lead to my system charging the batteries, it is instead selling the excess solar energy back to the grid. This is puzzling, considering the system should be incentivized to store the energy under these pricing conditions.

Attached are the screenshots from my system's dashboard. As you can see, the grid is showing a negative draw (indicating that energy is being sold back), and the battery state of charge is at 19%, with the system actually discharging instead of charging. The PV inverter is generating 4543W, which seems to be ample for charging.

The second screenshot shows the energy consumption and solar production data, which also suggests that there is enough solar energy being generated that could be stored.

Could this be an issue with my settings, or is there a possible fault in the system that is causing this counterintuitive behavior? Any insights into settings I should check or adjustments I should make would be greatly appreciated.

Thank you all in advance for your time and support.

Best,

Leon

Yesterday it sold also amost all my solar energy, for now i switched off DESS and charged my car to get most out of the pricing and solar

During some export testing today I noticed that the target export power wasn't reached. Reason battery temperature was only 15°C so the BMS was limiting the output currect. Maybe it would be idea to have a relay output to start x-time before planned charging/discharging to preheat the battery (like EV's also do). Otherwise big chance planned charging or export shedules will not run complete as planned.

What do you think @Dirk-Jan Faber (Victron Energy) ?

I noticed the following behavior. during the day, buy price were low (~19ct) and during a period of no sun battery was used to drive the loads.
But at evening buy prices will be high (~29ct).
So from my opinion it would be better to feed load from grid during low prices and use battery at high prices in the evening?

I am on beta v3.30~11 and ESS assistent is up to date.

Hello @Dirk-Jan Faber (Victron Energy)
Yesterday and today, the electricity price is at 16-17 cents. Rain is forecasted for the next 2-3 days. Why doesn't DESS plan to charge the battery at 16/17 cents?
Andi

Today DESS almost disabled solar power and charged from grid. This is not normal.

Had to disable charger to use solar. Is it possible to limit SOC % from grid to leave room for solar? Sell to grid is disabled.

About to install EVCS next week and this behaviour would make Auto mode for surplus solar useless.

MP-II charger enabled

MP-II charger disabled

Hello @Dirk-Jan Faber (Victron Energy) , the forecast for the next three days looks pretty optimistic. At Wetteronline.de there are only 3 hours of sunshine and in VRM 100kWh from 20kWp. Something doesn't add up.

Hello, I have a little alarm sign at the status screen on the Cerbo. Looked into VRM: no active alarms, Looked in the Cerbo: no notificatios. Put the multiplus out and on: it w'ont disappear.

Put the BMS out and on. no change.

Where can I find this errorcode ?

Running version 3.30~13

Hello, I am missing the little button in VRM from DESS (buy, sell, off) in the top right corner of the VRM screen. Tried to claer cache and diffrent browsers but no change. When I put the slider DESS off and again to on then its apears shortly and goes away again.

with regards, Axel

c0619ab4b607

Solar irradiance forecast for today is 3 times less than yesterday but DESS still thinks that there will be more production (6,0kWh) than yesterday (5,8kWh). It doesn't make sense. Or what am I missing? Forecast for yesterday was almost spot-on. id 48e7da86cd8b

Solar irradiance forecast Solar production forecast for today

v3.30~15

Still the same issue, DESS is throttling production of pv inverter

https://community.victronenergy.com/questions/265862/venus-os-v33010-available-for-testing.html?childToView=266052#answer-266052

Protocol continues having problem :

Current situation :

SOC = 10% (= minimum)

Forecasted consumption till 24h = 6.1KwH

Forecasted production till 24h = 7.9 KwH

Result till 24h there is a theoretical left over off 1.8KwH

DESS planning = injecting 1.8KwH in grid during production time

BUTT

From 24h till production next day is higher then consumption there is a need for 1.58KwH & this won't be there annymore. We started on min SOC and will end on min SOC at 24h.

Conclusion : grid export should be blocked!

Any export is blocked if (Sum consumption untill next day production is large then consumption) >= (forecast production in the same period + safety margin)

Quiet sure if you add this in 99% off the cases DES will work correct. Weak point stays off course that the predictions must be correct but rechecking the condition every hour will correct a lot.

@Dirk-Jan Faber (Victron Energy)

Firstly, great work! Very happy with DESS so far.

A few questions regarding system efficiency:

- Is the current RTE used by DESS still 85%? Looking at the Multiplus 2 efficiency curves for the charger and inverter that seems a bit too high in most cases for energy arbitrage.

- Would it be possible to expose the round trip efficiency in the VRM interface?

- Would it be possible to use the full efficiency curves for the charger and inverter? So taking into account that slow charge/discharge is sometimes more beneficial due to efficiency gains?

- Is AC charging from grid and DC charging from MPPT handled differently efficiency wise by the optimization algorithm?

@Dirk-Jan Faber (Victron Energy) Can I edit this parameter depending on my actual SoC via NodeRed? I would like to try to allow feed in only if SoC > xy %

I could not find it or searched the wrong nodes.

Dirk-Jan Faber (Victron Energy)

Please set in Estonia battery usage one hour earlier. Us day electricity day tariff started at 7:00 and ended 22.00. Weekdays. 7.00 is is a strategically important time. People wake up to go to work, and that's when electricity is used the most in the morning.

The biggest change concerns the night transmission fee. It is undoubtedly positive for the customer that the time of use of the nightly, or cheaper transmission fee, will be extended by one hour on weekdays and will be valid all year round from 10:00 p.m. to 7:00 a.m. Also, in the future, the cheaper transmission fee will apply 24 hours a day, in addition to weekends, on national holidays from Monday to Friday.

https://www.elektrilevi.ee/en/uudised/avaleht/-/newsv2/2022/02/18/1-martsist-pikeneb-elektrilevi-kliendile-soodsama-oohinna-kasutamise-aeg-ja-lisanduvad-uued-vorgupaketid

Hello team,
I'm curios why my system plans to not charge the battery more with Dynamic ESS Active:
Actually currently he doesn't want to charge the battery and only feeds in.

VRM ID: c0619ab1f6b5
I configured it yesterday evening (Tibber dynamic price for buying and quite low price for feed in). As I have some Server equipment my battery needs a minimum of 45% at 00:00 to be full enough to not use grid during night and in the morning beeing at ca. 15% which is my SoC lower limit.
Lateron I'll update the Multiplus and install ESS 18c and see if that changes anything.

Additionally there might be an issue with the future price, as price for the next day is published roughly at 13:00 for the next day thus maybe tempering with proper calculation.

Thougt I would download latest Cerbo firmware and give DESS another go. It's still making weird decisions though.

Why would it not charge battery from 3-5am @ 7.5p/kWh (for use once cheap rate ends) rather than the 8kWh @ 30p/kWh from the grid between 5-8am?

VRM ID: c0619ab38079

@mvader (Victron Energy)

I more often get the below error message in VRM regarding DSS. What's the reason for this? I often oberserve it after Firmware Update of GX. An additional switch off and on of DESS in VRM seems to clear it. Is it on your side or on my side? ESS assistant of MP is already updated.

Hello, I noticed that the battery charging schedule is often not fulfilled. In the attached photos, there is a day when DESS was supposed to charge the battery from solar excess all day. Unfortunately, I don't have a photo from the morning. In the end, it hardly charged from solar panels at all, but only from the grid. Yesterday, I upgraded the FW to version 3.30~17, and today DESS behaved very well. Could it be that the issue is already resolved?

DESS do not feed to grid when battery is full.

I am using DESS for several months and in general it works fine.

Now I found a problem and may be it is related to DESS :
- I am from Germany and here it is not allowed to feed battery power into the grid, if you buy batterie power from the grid. But i can feed solar power to the grid. Therefore I have disabled sell to grid in the DESS configuration.
- Now I have seen several times that, if the battery is full and DESS wants to keep it full (DESS final SOC is 100%) the output power of the MPPTs is reduced to a very small value.
- If the battery is not at 100% then the output power of the MPPTs is again maximum and charge the battery.

I have made in NODE-RED a logic to switch to SELL Mode (DESS MODE = 3) when the battery SOC is > 99% and switch back to AUTO Mode (DESS MODE = 1) if the battery SOC is < 98%. Now the MPPTs output power keeps the maximum and I feed into the grid.

Question : Is this the wanted behavior or do I need to change any configuration ?
I do not want to sell battery power to the grid, but I want to sell the maximum solar power to the grid.

Thanks for any information.

v3.30~21: consumption forecast wrong

Since my system went live, I have never had a nighttime consumption of less than 250W, typically 300W.

Nevertheless, the forecast regularly (every day for some time) manages to predict 0 consumption.
There are no large household atypical consumers.

Is it just my system that has this behavior?

Using DESS since the very beginning.

Seems like working for me. Thank you.

What I have lack of - would be great to have "Keep batteries charged - 0 price" or add ESS modes prices during specific periods during a day.

Example - I have AC in for my DESS from another Solar setup. I'm switching from "Optimized without Battery life" to "Keep batteries charged" when there is a solar excess on AC in 1.

DESS is not showing this timeframe has 0 cost , it calculates based on my DESS fixed prices table data. Which is not correct for the graph.

On above graph - arrows show bars, that must become "economy"

Above in the red square - "Keep batteries charged" mode, forced by me via NodeRed, cause 230V on AC in 1 - excess solar from previous system in cascade.

https://betavrm.victronenergy.com/installation/380883/share/813a14fb

Previous system in cascade just for the reference

https://betavrm.victronenergy.com/installation/370388/share/c0152a83

Technically , I see this as adding column for mode's price in DESS table

This would be helpful.

Thank you @Dirk-Jan Faber (Victron Energy)

@Dirk-Jan Faber (Victron Energy)
After updating to release 3.30 (not beta) and installing the v510 on the GX (including New Assistant) I get an error on VRM. "Gateway - Dynamic ESS error code: ESS functionality not available"
After upgrading (two days ago) to 3.30~18 I already got an error "Dynamic ESS error code: No matching schedule available". But after a restart ot the Cerbo this seems to be gone (although I didn't see it in the graph on VRM.
I also updated Node-Red version to 0.1.17.
I am not able to see the dess dashboard anymore via the proxy since about one week. It just doesn't load anymore.
And I am not able to see the node-red directly on Cerbo (venus.local:1880/dess) because I get an error: site can not be reached. Where venus.local is my local ip. Just going to the ip brings me to the console.
So I am going into the blind right now. The first thing I like to fix is the Dess is working again. Thanks for any help.

Old screenshot from dashboard:

Update: 12:36
After resetting the Cerbo (again) the error has disappeared. But I still do not have pricing info.