Should I understand that you have access and knowledge of the Venus OS, as long as you’ve quoted that piece of code from dvcc.py?
Anyway, try first to update the Cerbo to the latest firmware and see if it solves the problem.
If not you can always revert to the previous version.
Hi not sure if This will help but enabling svs worked in this instance. ( if not already tried)
Hi Dave,
in my system the SVS is “Forced off” and cannot be changed for some reason.
Thanks
Ok yes some managed batteries do that, sorry it didn’t help.
Sorry one other question, when you put say a 3kw load on the system and there is excess pv power available does the RS 450/100 supply that power to the inverter or is it taken from the batteries?
Hi Dave,
when there is a load on the output, the DC PV will supply that power if it is available. It is not coming from the batteries. The only problem I see it is that it doesn’t feed in into the grid when it is needed.
Thanks
Hi @gpatti
If you don’t want to update to the newest firmware in Cerbo, I believe that your old (3.13) dvcc.py script from where you’ve quoted above, in the zone of the batteries quirks, for the Pylontech quirk it looks like the one below.
Try to modify the lines for the 15S batteries like in the picture below and see if it’s working.
The Pylons limit the CCL to 0 (zero) when they are full so the charger is stopped.
We are trying to work around this.
Hi Alex,
just to be sure : to make the change you are suggesting is it ok to just overwrite the python script and reboot the Cerbo GX?
Thanks
You just modify the orange circled part of the code, not the whole python script.
I believe that the original part of the code (on Venus OS v3.13, like you have) looks like:
if charge_voltage > 30:
# 48V battery (15 cells)
return (min(charge_voltage, 52.4), charge_current, feedback_allowed, False)
You’ll change only the above portion of code with:
if charge_voltage > 30:
# 48V battery (15 cells)
capacity = bms.capacity or 100
return (min(charge_voltage, 52.4), max(charge_current, round(capacity/4.0)), feedback_allowed, False)
Don’t forget to make a backup copy of the original dvcc.py file as a precaution.
And yes, after that you reboot Cerbo or for quickness you can just kill the dbus_systemcalc process and the system will reload it with the new modification.
Hi Alex
Unfortunately, this change is not solving the problem. I believe this modification may only affect the charging current of the battery. However, from what I understand, that is completely controlled by the battery’s BMS. My suspicion is that something might not be correctly configured in the process (let me know if you agree). The expected behavior would be for the Cerbo GX to send information to the Smart Solar MPPT 450/100 to attempt to regulate the battery voltage 0.4V higher than the final battery regulation. This way, the inverters can use that energy to feed into the grid.
The firmware has been updated but it doesn’t solve the problem either.
I would like to try the following:
The actual code is:
I’m not entirely sure about the syntax, particularly for the part checking the SOC.
What do you think?
Thanks
First try to see if the increase in voltage is solving your problem.
If you are using dbus-spy, see that in the com.victronenergy.system, you have several keys that begin with /Debug/…
Play a little with SolarVoltageOffset and/or VebusVoltageOffset.
The values are in Volts, so be careful and use values below 1. In other words 0.xx.
Just select the key, hit enter and an input prompt should appear in the lower part of the screen.
This should increase/decrease the charge_voltage variable, in other words /Link/ChargeVoltage.
But just increasing the voltage when the charger is current limited is not enough.
So you may also need to allow the charger to “produce”, so, what I’ve suggested with the code above for charge_current should also be applied.
But you can simulate this by tuning the CurrentOffset on the /Debug/… keys.
So, for starters, if I were you, I will leave the scripts alone, not modify them at all, and, when SOC is 100%, I would set SolarVoltageOffset to 0.4 and CurrentOffset to 30 and see if the feed-in starts.
Beware, raising the DC bus voltage could also influence your battery voltage which is tricky…
But also the point raised by the WhiteCitySolar in the message #4 about grid code is a valid one.
If grid code is properly set, then the feed-in should not malfunction…
Hi Alex,
ok, thank for your suggestions.
Yes, I forgot to reply to WhiteCitySolar , I have checked the grid code and it is correct.
Regards,
Giuseppe.
Hi Alex,
I have tried all possible settings, but nothing works. For some reason, the feed-in from the DC PV is not allowed. What are the possible settings that could prevent the feed-in from the DC PV to the grid?
Thanks
We have about the same setup. I’m on 3phase using Enphase on both ac-in and another one on ac-out, I have pylons and the MPPT RS 450/100.
In another post I raised a question about the MPPT temporarily (1 to 10mins) stopping production once the batteries are nearly full. The multi’s continue charging so we’re not yet at CCL=0 but the MPPTs need to switch to another algoritme maybe ?
It’s quite a complex thing to invert/feed-in the right amount of electricity when the Pylons acting as a buffer for shading are hitting 100%.
Till now I never figured out what makes the MPPT stop and restart. I think it stops at 52,5V battery voltage but have no clue when it restarts as in the restart occurrences the voltage reading were not the same.
Back to your problem. I did not set anything other than what’s mentioned earlier in this thread. I do know that I have never seen the 52.4+0.4=52.8V mentioned earlier. But with a 1min VRM resolution that doesn’t necessarily mean it’s not happening.
In an effort the fix this issue I do remember setting the recommended charger config in the MPPT charger but that did not change anything. I guess the settings are only used if DVCC is not working.
Hello,
I have the same problem here or the same symptom at least.
The setup is a Multiplus-II 48/5000 with a MPPT RS 450 and a DIY 18S Lithium battery running ESS and allowing DC feed-in.
When the battery is fully charged the MPPT doesn’t feed into the grid. At this moment the battery voltage is around 62.5 V (18S battery).
I read this on the MPPT manual :
*******
The Charger set-point (float and absorption) can be set to max 60 V. The output voltage at the charger terminals can be higher, due to temperature compensation as well as compensation for voltage drop over the battery cables. The maximum output current is reduced on a linear basis from full current at 60V to 5A at 62V. The equalization voltage can be set to max 62V, the equalization current percentage can be set to max 6%.
********
So I am not sure if I am having a problem because I am running a 18S battery or because of something else similar to your unsolved problem.
Cheers,
Julien
