i was reasonably ok with DESS the last half year, but this week i regularly see optimal forecasts but lousy application… Why is DESS not charging at full potential during the cheapest two hours? [image] from 12-13 it charges 10 kWh (4.4 from grid at 3 ct/kWh) from 13-14 it charges 7.7 kWh (1.9 from grid at -6 ct/kWh) from 14-15 it charges 9.7 kWh (3 from grid at -8 ct/kWh) from 15-16 it charges 8.9 kWh (3.7 from grid at -1 ct/kWh) and still charging from grid between 16-17 ( 9 ct/kWh, at this moment 10kW to battery of which 6kW from grid…) Battery is now at 83% meaning it can still tak almost 10kWh Why not 10kWh during all 4 periods and maybe less between the more expensive current hour (16-17). I’m worried what will happen tomorrow when we have prices of -35 eurocent per kWh between 13-15 hr… Forecast for tomorrow: [image]

[image] marcelmol: Why is DESS not charging at full potential during the cheapest two hours? Because DESS (Trade) will only buy what it knows it can sell profitably upto the end of the known day ahead prices schedule. And automatically attempts to reach ‘MinimumSoC’ at that same “end of schedule” moment.

As i sort of expected DESS does not start to charge the battery now the price is very favourable, and we are already 10 minutes into the hour. So i just switched off DESS and set the ESS setpoint to 6000W to force it to charge

[image] Jan: is trivial easy to see this flaw play out in full force/glory, simply because low to negative prices remove that upward SoC bias (no I’ll check out your suggestions later Jan, and play with it. I’m running DAO in homeassistant as shadow manager and beginnig to think to swith to it…

had no time to look into it Jan. You mention doing this virtua EV in the VRM console, but do not see how. Or do you mean in Node-Red. (I lost my cerbo a few months ago (suddenly stated to make clicking sounds and stopping all funtionality) , loosing all my node-red setup (no, no backups…), just got a replacement after over 4 weeks wait. ) SO if you want to share the node-red setup fot this, I’m happy te try out the viirtual EV hack (maybe call it somethin like ‘rightDESS’)

Jan, it may be helpfull to show 2 pictures each time you change teh virual EV load. One showing what DESS plans without the EV load and then one showing what it does after adding the EV load. So users can easily see the real difference!

Pretty shocking to see that a cheap Chinese Vevor Hybrid inverter can handle this and Victron fails to fix this,

I can see the effect of the extra load you pose on it in the forecast, but to see what is actually happening the price and energy graphs should also be shown… hopefully vitron staff will then care to omment too :wink:

Vevor has a Dess trial project for a future firmware upgrade. One of the developers shared a vlog about it, but it was later taken down.

So you’re comparing an imaginary product that you haven’t tested to one that does exist, albeit a work in progress? Do they have a community forum with a good grasp of English and where engineers try to answer questions where they are able? It is always easy to pick fault, show me a Chinese manufacturer where you have a vague hope of interaction like can be done here, and I fully appreciate that interaction may underwhelm some expectations, but for the most part it helps an awful lot of people.

Right. I myself have not used the product, and I have no intention to do so. But the hardware is available and can be ordered worldwide. But we are talking about software, and yes it is hard to communicate with China people. In English. Fair point. Luckily Chine has license and patent pools so I guess that it won’t take long before other companies will introduce this feature as well. I would like to point out that I am very happy with the hardware, and the forum et all. Really. But not so with Victrons implementation of DESS. I do have high hopes that everything gets sorted, but for now it is not something that I can use.

Why not charge at full speed during cheap hours/

Q&A and troubleshooting DESS

Pim57 (Pim) 5 May 2026 05:52 25

This is working as designed and will be addressed in a future update.

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Why not charge at full speed during cheap hours/

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