When my system is at 100% SoC an erratic discharging/charging control loops starts to occur when in absorption charging, There is plenty of solar feedback into the grid available, thus discharging is absolutely uneccesary.
See example here:
The charge/discharge currents are very low, between 0.8/2 amps. I would expect a constant constant absorption charge
I would expect a very low charging current, and an eventual ‘idle’ state where no charging is happening anymore or when the absorption time limit has exceeded ( victron setting ). However this is not the case, it keeps toggling between charge/discharge until there is no solar available anymore and permanent load is put on the system.
I could find quite a lot of related issues/topics on the internet, but all without any solution or clear answer on how to prevent this behaviour. Or is this behaviour intended from the ESS system? Up until now I could not find any clear documentation.
Fairly normal for some batteries, the bms is trying to balance. It can be exaggerated by diy bms’s which will need to be tuned…
This bms is unsupported so it will need some trial and error.
Thanks for your response @JeroenSt . Is this peak shaving also occuring while there is only feedback into the grid? There is absolutely no need for the system to do this peak shaving, since there is only feedback towards the grid.
Peak shaving only applies if you have set a low input current limit and are drawing more load than that.
In your case your loads are small.
The numbers in that pic doesn’t stack up. 1300W PV, 44W to battery, but 963W load and 1100W being fed back.
If you aren’t trying to draw more than 40A, it wouldn’t be trying to discharge the battery.
Some batteries will naturally fluctuate as a result of balancing. For the OP it doesn’t appear that peak shaving should be a factor.
When peak shaving is disabled due to minimum soc the charge discharge flipping doesn’t occur.
It is the victron that starts discharging for a short time when a load is switched on and starts charging for a short time when a load is switched off.
I think the regulation loop is triggered when the current changes before the maximum current is reached to be fast enough when the current limit of the grid exceeds.
Again, on minimum soc when peak shaving is disabled this behavior doesn’t occur.
Unfortunately there is no setting to disable peak shaving permanently.
These numbers indeed do not make any sense. It looks like the calculation from AC-loads is wrong.
Grid data is coming trough the P1 port into the dbus.
At least the ESS system is working perfecly fine, it’s regulating nicely to the grid setpoint.
Currently there is nothing connected to my AC-out port of the multiplus II.
Here an example where you could see the AC loads beiing calculated wrongly, actual AC loads should be around +/- 300 watts.
It doesn’t look like your meters are configured right. If they aren’t victron gear and are third party ones with OS mods, that is something important to mention.
Until the system is reporting right, drawing any conclusions on why things are behaving the way there are is premature.
