Hello all,
Somehow my vrm decides to discharge my battery at low prices when i add loads like an ev.
I thought it had to do with negative prices before but now i don’t have negative prices but low prices.
I have updated all my software, my prices are marketprice +0.02 euro.
Somehow it’s trying to put my grid at zero even at those prices.
Does anyone has similar issues?
Hi,
This “depends” is the answer. DESS is not a 24/7 always-on EMS deciding in seconds. Generelly your system will be doing ESS, so driving loads from battery is the “default”.
DESS then will just add some managed timeframes to the day, i.e. deciding when to force charge, force discharge - or just idle to favor the grid.
The driving factors behind these instructions are solar- and consumption forecasts.
And your day there is plenty of solar, very little expected consumption - your system quite sure is running in vanilla-ess mode.
Only if the scheduler would see, that there is a need for energy from grid, it will start to apply strategies on certain timeframes, to “direct” grid pull into cheap hours.
As long as you see the scheduler expecting 4 hours of 100% Soc, it won’t encourage energy beeing pulled from grid by adding constraints anywhere.
It will re-evaluate that every 15 minutes, tho. So, by the time the last 100% hour vanishes, it will still allow battery to be used and reduce the amount of bat2grid planed for the evening.
Then, if that all is 0, and your SoC starts to no longer be sufficient through the night - then it may decide to idle the battery during cheap buy-hours or even charge the battery from grid.
My DESS is turned on in vrm and i’m in trade mode so i woudn’t expect this behaviour.
But that’s a good point that it expects to charge to 100% easily today.
I did have 2 cents in my buy/sel formula so maybe it’s avoiding that.
But even then it would be better to charge as fast as possible when energy prices are cheap and export maximum amount of solar at higher rates.
The difference in energy prices today are way higher than the 2 cents.
A, trademode it’s a different scheduling. The scheduler generally decides to keep the battery as empty as possible before the “best buy opportunity”.
So, feeding the ev from battery “supports” that. If you would do the maths on that (can’t see your prices) it will quite sure work out.
If the current buy price is a bit higher than what you will buy for later (after losses and roundtrip costs) - then, spending battery on the ev does make economical sence. It’s then basically “charging ev now and buying later for less money”
It was discharging at 14:00 when prices were at minimum of the day.
Now I’m at 50% soc and prices are rising already:
This means that it will charge from solar that i could sell for an nice price if battery would have been at 100%.
And even now it’s charging only to keep the grid at 0 import. So it’s charging slow when i don’t have enough solar.
So long story short, i must have put a setting wrong somewhere because it keeps the grid at zero way too often.
