Hello Victron,
Please explain how “Battery balancing is scheduled for this day” works and how it affects scheduled selling to grid?
Thanks!
I seem to have a problem where DESS schedules Battery Balancing for several consecutive days. I ended up turning it off.
My Lipo batteries charge to 100% and hold there for the absorption and the moves to float after 1hr. The voltage as programmed drops and the charge state moves to 99%.
Last week it stayed at float 99% for over 6 hours. And still called to balance the next day.
Any ideas or should I just balance manually?
This problems seemed to resolve yesterday. The site charge fully and held at 99-100% for over 6 hrs. No battery balancing scheduled for today.
Re-launching the thread a bit, so I don’t have to create a new one.
Is there an option to manually choose which day the battery balancing will be done ?
I’ve got the message that it’s scheduled for today (a cloudy and rainy day with high grid prices) while during weekends grid prices tend to be much lower.
I decativated the schedule. It reported as being due for tomorrow, although the battery reached 100% for the last 5 days, every day…on a schedule of 14days … useless feature.
Well - when it’s enabled for the first time, it will not take into account when battery was on 100% in the past and just assume it never happened.
Starting with September, my PV yield is not enough to fully charge my battery, so I enabled this feature on a weekend and set the period to 28 days because on weekends we have the lowest prices, mostly at night. And there we go: DESS scheduled balance charge exactly during a low-price period and that’s it. No more balancing was performed since.
But being able to set allowed / disallowed days and time slots as well as max price for charging from the grid would be much appriciated.
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Easiest in my case would indeed be to disable and re-enable the feature over the weekend.
A “Don’t balance today, the weather is shite and prices are high” button would be a “Nice To Have”, but maybe a bit overkill as well.
Yes, I would welcome this too!
It would be even better if the algorithm that sets the time to balance battery utilises the solar forecast and energy price forecast around the scheduled battery balancing date. Then chooses the optimum window to balance the batteries, rather than a manual intervention to prevent it.
I appreciate forecasting forward energy prices is hard and will be different in each country depending on the generation mix. Where the mix is high in variable output renewables it should be possible to estimate from the weather forecast and historic data the level of wind and solar energy and hence the energy cost.
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I’ve been pondering about the max price to balance, but in the grand scheme of things I’m not sure if it would really make such a difference.
Let’s say you need to charge 20kWh and the grid price is €0.25/kWh higher than bottom price, then the extra cost of charging would be €5.
Meh.
That’s too much, that’s a beer!
In my case, it did start charging at the bottom energy price of that day, so that’s OK.
With dynamic pricing, there’s only 1 day to look ahead so forecasting further would pretty much be like voodoo or just wild guessing.
The easiest solution I guess is to enable balancing on a saturday or sunday, when energy prices are typically the lowest, and from there on just wing it.
My example was rather exaggerated 
Yesterday DESS started balancing my battery at €0.15/kWh (lowest day price) and finished at €0.23/kWh (highest day price).
The delta was only €0.08/kWh so that costed me like an entire € extra shocked.
I think I can live with that
Yes, sorry…the described behaviour occcured on the second iteration of the cycle…hence, useless.
I did charge my battery to 100% last Sunday and today the balancing kicked in (again). It started in the best hour, but stopped one hour later (same cheap price) at 70% SOC and finished the charging during the second most expensive hour of the day. Also dinner cooking without the battery and expecting a sunny day tomorrow. And yes, 7h later it’s using the battery again.
Setting the balancing to Sunday afternoon would be preferred. It’s typically the best price and on Monday the price is the worst. An automatic full Monday battery would be perfect.
