The roadmap indicates an intendet discharge to grid.
The system retrieved a proper schedule to do so starting at 07:00.
The system responded to be in the proper discharge mode and applied the desired dischargerate to the battery.
but the system didn’t do it.
I will see, if I can figure out why. Something seems to prevent it from discharging at that time.
Strange thing on top:
The window 19-20 yesterday was also a scheduled discharge to grid. (Same settings as in the morning hours)
Your system did nothing upto 19:36 - and then started to discharge as scheduled, but ofc. didn’t manage to reach the intendet discharge-volume in only 24 minutes left.
Thanks @dognose for your time and feedback. Appreciated. There is an second topic on this subject, in which I stated that I found the solution. An firmware upgrade to the Multi RS Solar resets the Grid code, hence the system was not allowed to return any power to the grid. I configured the Grid code correctly again and it seems to be working again. For now, no action required.
Well, the original issue I started, why is the PV returned to grid instead of into the battery, seems to be still open and applicable! It is still happening. @dognose this is maybe still interesting to investigate.
The energy pricing is going to a low price, battery is discharging (only small power), but there is 1.3kW returned to the grid. Why is this not going into the battery so it can be sold later at a higher price!
An hour or so later, the PV power is put into the battery! As I’m expecting. So maybe the previous situation was still because the energy price was high enough.
Energy price at the lowest today. My expectation is that the battery is being charged with max amps/power! But this is unfortunately not happening. There is even power returned to grid! Why is this happening. The power should go 100% into the battery and at this low price, the power should be pulled from the grid at maximum rates! See screen shots. @dognose suggestions?
There is something still not working as expected with your system it seems.
The Schedule was to buy 3 consecutive hours 13-16 here. (Applied chargerate was 7500 Watts as to your most recent configuration changes)
Actually, 1 hour was scheduled, but DESS keeps postponing that as your system does not charge during that hours as expected. Currently requesting to charge with 7500W in the 4th hour.
didn’t happen. System reports to be in charge mode, but the actual chargerate of the battery is not even matching your solar-excess…
From 13 to 13:20, it charged with 3000 watts (instead of requested 7500) and then dropped to 855 and continiously lower… (orange line)
What are the specs of your battery? What Charge-Voltage settings do you use?
Currently, your BMS is requesting a chargevoltage limit of 55.2V, battery is at 53.62 with 50% Soc.
At least I can tell, the Issues are not related to DESS itself. It is requesting charge / discharge as scheduled, but the system does not properly fullfill that job.
Do you have enabled DVCC in the local GX? Any chargevoltage limits applied here?
Is BMS controll enabled?
Even at ~16:00, when you disabled DESS temporary - the chargerate of the battery didn’t increase. So, even Regular ESS Mode couldn’t make the battery charge at that time.
Seems like the BMS is refusing that for whatever reason. Can you check the BMS for any Error / Warning Logs if the JK has some interface for that?
Your Inverter is now reporting “float”. So, that seems like you disabled BMS-Charge-Control and the Inverter is falling back to it’s values set in VEConfigure.
You should enable DVCC, and set the control to the JK BMS. BMS knows best what It currently can handle:
Thanks @dognose for your support. I’m not at home at the moment, cannot check the BMS charging details/settings. Will do this on Sunday. I’ve copied the setting from the Off-Grid-Garages website: JK Inverter BMS (JK-PBxx Series)
well, thats for the cerbo / GX ui. Do you have one? Else I would need to check how that’s configured on the multi-rs
This then should resolve your issues. It seems, like you have configured the Non-BMS-Chargesettings to low:
The battery was charging with only 3000 watts, indicating a way to low chargevoltage,
By the time the battery reported 53.8V for a split second, the inverter switched to float (i.e. lower charge voltage setting, leading to an almost 0 charge rate.)
You could change this settings as well - but delegating that stuff to the BMS is just easier and the BMS has more parameters (temperature, Cell balance, etc.) to determine a suitable chargevoltage / current dynamically.
Thanks again @dognose. I’ve changed this configuration remotely. DVCC is enabled and the JKBMS is selected. I will continue monitoring the situation again.
Hey @dognose - not to go off topic but are you able to share how you graphed this diagnostic data? I can see it’s in grafana, just wasn’t sure if these data items are easy to pull from VRM. It’s super helpful.
Some of your problems come from (green) DESS not working the right way.
When scheduled, it discharges/charges every hour to a certain percentage.
It reaches that percentage normally in 45-50 minutes. When it does reach that, the system doesn’t go back to normal operation, but stays in a certain state where it uses grid or sells to the grid, but exactly in the wrong way.
So sell solar when cheap, buy the power needed for loads when expensive.
This is just a bad way of functioning from DESS. Not only because of this problem, but also because you loose every hour 10-15 minutes of charging or discharging at the best prices.
They should just change that to let it discharge till a certain percentage over a few hours and when it is reached, return directly back to normal operation.
Also, it would be useful to have a separate minimum SOC for (green) DESS, so you have not the problem that when you use a bit more power than expected, it starts using grid power at the highest rate because the minimum SOC also means stop using battery.
I wrote about this in a Vrm topic, but didn’t get any answers from the victron staff. @dognose
This is not correct. DESS schedules the maximum charge according to your maximum configured chargerate.
That means, if your battery is capable of charging for example 8 kW, the schedule will calculate the targets, so 8 kWh will be purchased in that hour.
If your system reaches the target SoC early, it is an issue with the BMS reporting a incorrect SoC-Value, not a schedule problem.
Basically saying your BMS then reports to have 8 kWh charged as scheduled - but in reality hasn’t.
To work around this issue, you could set a maximum chargerate beyond your batteries capability (for example 12kW).
Then, DESS will schedule to purchase 12 kWh in the cheapest hour and the system will charge the battery at it’s maximum rate, trying to achieve that purchase.
Exagerating the rate by 50% will most likely cause your system to not reach the intended target, but cause a non-stop-charging accross windows and not hurt all too much, the schedule will adapt.
You could play around with that value to see, what compensates your imprecissions caused by soc-values of the BMS best. Missing the hourly target by about 1% would kinda be the best tradeoff between seeing continious charging and having dess to do only minor corrections for the next hours.
Having it too high will cause DESS thinking it could be achieved in 2h, while in reality it needs 2:30h - then the missing half hour may drop into no longer optimal prices or even be omitted cause it’s no longer benefitial to keep buying.
On a side note: You should try the new beta. Here this behaviour has been addressed by keeping up the current chargerate, when the target is reached early, but within the last 10% of the window and the next hour schedules another charge as well.
This may not kick in for your 15-min early fullfillment, but avoids drops to 0/idle of upto 6 Minutes between windows with the current schedule size.
@dognose why is the system returning the solar engergy still back to the grid? We are heading to the lowest energy price, I would expect that the solar goes into the battery. See screenshots.
