Balancing ; wouldn’t it be better to have a button to start balancing immediatly, or, plan it? Because, what happens now; it’s descharging to the grid right now. Then, as it’s saying it will be balancing today, it will go to 100% at a moment which is financially no good. I completely miss the logic behind this.
Dynamic Prices. Right now, it doesn’t act as it should with the buying and selling prices. If I put in the selling prices are 20% lower (which is always the case due to warmth losses), it should look at this before it decides to buy or sell. And, even better, if we can then, also put in a minimum margin.
And, I said this before : there are 2 places to switch off Dess. I wax told here that one button keeps showing the planning, the other doesn’t. But this is not correct. As soon as it’s pass midnight, the planning is gone anyway, for that day. So, why 2 options with the same description?
I hope to get an answer soon to these questions. We have our victron system now for 5 months, and it’s a day task to keep an eye on the system. This is, definitly not how it has been described and sold to me!!
Only solution that I can think of is having node red to take care of stuff.
So, no reaction at all from the Victron people? That’s really bad, since my installer says, you know, I don’t know so much about Dess, better ask at the community.
Last addition ; in the Netherlands rules are changing when it comes to “salderen”. From 2027 the price you will receive for injected kwhs Wil be only the het price. I do hope the system will be fixed then?? So that it takes the prices into account when selling or buying kwhs?
I am not from Victron. But I do have a Victron system running. And I actually always have DESS active. And that works really well here.
Indeed, once every 14 days the system balances the batteries; that is for the preservation and lifespan of your batteries. And indeed, then it might briefly buy a bit of “expensive” power for that day.
But otherwise, it works really very well here.
But let’s start at the beginning. What kind of system do you have?
Can you tell me a bit more?
Which DESS mode is your system running?
Have you entered the battery details correctly for DESS?
Have you set up the pricing formulas? And are you sure they are correct?
All really simple things…
And it seems silly that I’m asking about it… But I do suspect that the issue lies somewhere there.
You can change balancing to once every 30 days, or turn it off if your system already reached 100% by itself often enough (that’s what I do).
Make sure you use Trade mode (for this year, next year switch to green mode when salderen is gone).
Don’t remove 20% of the selling prices, there already is an internal percentage for this which defaults to 90 (you can change it using eg node red). If you want a minimum margin (in cent per kWh), you can use the battery price for that.
Then it should mostly be fine, except for some stupid self consumption which DESS does ( therefore I have my own logic in node red using the Victron provided schedules).
Yeah, I turned it off, as it keeps balancing at wrong times. Plus, it doesn’t reach 100% anyway. Something I will adress at my installers adress soon. He sais it’s normal, a software error.
Prices; well, in my experience, (in winter) it does not work with any losses. We saw it planning to sell for 4 or 5 cents ‘profit’. Which is wrong, as those 4 cent are your losses already. This bahavior is in green as well as in trade mode. We always have it on green mode, trade makes no sense at all.
Now, in summer the system (green mode) makes more sense. Including the self consumage. Like this evening : solar was less then predicted. To it took away the selling, does sell consumage while prices are high tonight, tomorrow it predicts lot of sun and plans to dump all at the even higher prices then tonight.
Our system is : 3 x Victron Multiplus II 5000 48/70-50, a Victron Cerbo GX controller, and 4 x 11,7kwh battery
We mostly have Dess set at green. Or, switched off when we don’t agree with Dess. Especially in winter it happened we switched it off day after day, as it wanted to trade for just a few cents.
Battery details : wel, done by the victron installer, I sure may hope so. They went trough it again lately, all should be ok
Pricing:definitly. But sell and buy the same as it doesn’t seem to work with these figures when it comes to planning. I sure hope that they will change this in 2027,otherwise Dess will be useless in the Netherlands.
I have no experience with green mode, as it’s ment to optimize usage of solar energy and not profit. Which makes no sense as long as ‘salderen’ (buy=sell) is possible.
The trade mode schedules are perfectly fine as far as I am concerned (unfortunately the local scheduler does not always stick to the plan).
Just make sure your system efficiency is set to 80%. Messing with the prices is not needed. And use the battery cost for the the minimum profit you want to make.
My main concern is in winter. In summer, or like now, it works acceptable. And salderen, yeah, sure, but if trade mode uses simular low margin as it did in winter, it really doesn’t make sense. Must say, I never tried battery costs, to let the system decide when to buy or sell.
A few things about the screenshots of your parameters. Is it true that your house connection can only deliver a maximum of 17 kW? I’m used to higher power outputs in Germany. How did you arrive at the charging and discharging power values? Did you enter them yourself, or did your installer? Also, regarding your forecast graph: Why does the planned battery state of charge (SoC) drop so drastically in the evening without any calculated consumption? Is the system planning to feed power from the battery into the grid?
I am not in Germany, but in the Netherlands. These figures are entered by the installer. And yes, this is the max, based on the electricity connection we have
Not sure what you mean with calculated consumption, but yes in the evening it sells the solar energy, in most cases leaving enough for the evening or even night. So to take the own consumption from battery untill the sun is delivering again next day.
I know you’re from the Netherlands, you mentioned it. So the installer entered the charging and discharging capacities? 10 and 12 kWh respectively? For which technology? Which Multiplus model?
Yes, that was what he did. Plus, he told me that the settings there are only for Dess to calculate with. Does makes sense, as in the console are the system settings.
We have a 3phase Victron Multiplus II 5000 48/70-50
Okay, 3 x 5000 mAh batteries could be about right. Please monitor whether these values are roughly correct. Observe whether the average discharge power is roughly correct when the system is discharging. Similarly, observe when the system is charging from the mains. Please ensure that this is the actual power output and not some theoretically possible maximum power. Could you please send your battery costs again via screenshot? Your malfunctions must be coming from somewhere.
Perhaps a little more explanation as to why the charging and discharging power is so important. DESS uses this value to calculate its schedules. Many people enter the maximum power from the datasheets here. However, the actual power is lower because a BMS limits the power, the MP2s overheat and reduce their output, or the wiring has some kind of bottleneck. What happens then? The DESS calculates 10 kW of power and starts accordingly late, assuming it can achieve 10 kW. But in reality, for example, only 7.5 kW is reached, and the schedule is already off. THEREFORE, it is absolutely essential to enter values that are as close as possible to the actual achieved.
The charging power is quite high, that’s 4kw per multiplus, which can only charge 70a max, approx 3600 watt, but with a very low efficiency (below 90 for charging only).
I optimized mine to 3000w for both charging and discharging (I have the MP 5k also) that would make 9kW if you have 3 mp’s.
Also, if you don’t update the systemefficiency to a more realistic number than the 90% default that Victron uses, you will definitely loose money, especially when margins between sell/buy are tight.
You could ask your installer to set it to a more realistic 80%.
Battery costs are not a percentage, so that does not work the same as efficiency. At lower prices the impact of efficiency losses is just a few cents, the higher the price, the larger the impact.
