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Juraj Nikolov avatar image
Juraj Nikolov asked

ESS and DVCC ignoring max charge current setting

Why VenusOS ignore settings in ESS and DVCC?

In DVCC, I have set the maximum charging current to 100A ... but it charges more and ignores the 100A limitation, can you advise why? I assume that pylontech's BMS is superior (master) to that setting, and if Pylontech has the option to charge 148A, the system will charge 148A if it has that option...
In ESS, I have set the limit for inverter power to 4000W, VenusOS is ignoring this setting...
I also set the Feed In to 3500W and it simply ignores it, sending 4000-4500W + plus idle consumption of the object until the converter overheats...
Have you encountered something similar?All devices firmware update as latest


Thank you |:)

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ESSDVCC
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4 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

We had that topic already a few times, please use the search function.

Do you have DC feed-in activated?

https://community.victronenergy.com/questions/187320/dvcc-feedin.html


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Juraj Nikolov avatar image Juraj Nikolov commented ·

@Matthias Lange - DE thank you, I will look for it

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gazza avatar image
gazza answered ·

The first part of your post is explained in the DVCC section of the Cerbo/GX manual:

6) DVCC charge current limits are not applied to DC MPPTs when ESS is enabled with Allow DC MPPT to export. This is to get maximum output from the solar panels for export.

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Juraj Nikolov avatar image Juraj Nikolov commented ·

@Gazza thanks and it is some way how to sett. that DC charge (A) the battert under ESS ? Intresting is that wokrs fine (this dvcc) up to cca 6kwp ... wtih more kwp get max. output ... That is little supid not ? Or only way is add battery with which can hold battery system charge current and not start to burn :P

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gazza avatar image gazza Juraj Nikolov commented ·

Yes... if you size the battery bank and PV panel array correctly then this problem goes away. But, we all know how expensive batteries are and often we try and get away with the "least" number of batteries to get up and running? ( I would say that this is human nature, despite it sometimes being a false economy!)


So, for now we are stuck with either disabling DC feed in.... so that the DVCC CCL is respected, or sizing the battery bank large enough with respect to the MPTT (s) max charge current output and enabling DC feed in excess. There is another option and that would be disabling DC feed in until the battery bank has reached 100% and then switching feed in ON. This gets over that critical point when the batteries are getting above say 90% (just when they want to start throttling back the MPPT), often late morning when the solar irradiation is getting to its highest!! I have found that with my batteries (Pylon) when they are at 100% I can switch to feed in and the charge/discharge current is minimal even though I may be feeding 2kW to grid. But it is a pain to have to watch it all the time.


If you lower MPPT max charge current (easy to do in Victron Connect) and with my system it does respect this regardless of DC feed in switch position!

Here's an example of a typical "small" system with Multi-2 48V 3000/35/32/GX, 2x MPPT 150/35, 2x Pylon US2000C. So, at max the 2x MPPT could put out 70A which is greater than the 2x Pylon CCL of 50A. By changing the MPPT max charge limit to 25A they will not produce more than 50A...? This appears to be the case (you could lower it further if desired?). Its not a perfect answer... but I believe it does give a limited safety net. With this system it is not restrictive since the inverter is only rated at 2400W continuous anyway so I am not really exporting less than I want to.

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Juraj Nikolov avatar image
Juraj Nikolov answered ·

@Gazza

In connection with this topic, I am solving the topic with connection to pylons (parallel) + 2 x 15 280Ah cells, since I have them unused... It will not be controlled by BMS but by SmartShunt. So +- AutoBus, those cells can easily handle much more than 148A, which in my case is 4xU3000C, so I should be able to handle min. absorb from the MPPT 444A after connecting the given cells... ahem, now they are able to give me MPPT regulators 220A as it is quite brutal for the household and I don't know if I want to have it in the house :D

Yes, I thought of reducing the charging current on the mppt controllers too, but I didn't have to expand the PV array by 5kwp :D
I let the documentation get carried away, where it is nicely described how the mppt regulators will work together :), but yes, I admit. I overlooked the fjuture regarding ESS and DVCC...
For me personally this is a gross failure on Victron's part... it's as expensive as cocaine and they don't offer a solution for this as I've read for years... What can be solved by software.. Don't let anyone tell me it's not possible create an algorithm that will not correlate with what converter is used and how many there are + depending on the SOC. Otherwise, it can't happen that VenusOS alone, based on the data it has in the configuration, sends 200-300A to the battery ... but that's so stupid, that it sends the 200-300A ... : )) Completely stupid question :D system without BMS (BMS is there but not connected from VenusOS) only via SmartShunt, how does it know which CCL to use??? :D
I think that for the money they will earn from it and the law :) they could move their ass and brains as a unit on the market. ;)

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herculess avatar image herculess commented ·
It is possible by adjusting the grid setpoint, but this is done at your own and by software (nodered). but this regulation depends on software and i am not sure if i would trust that 24/7 ;)

i solved that by adding enough battery power.


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h8mecz avatar image
h8mecz answered ·

But what about L2 batteries - now I have 10,65kWh with nominal 100A charge current and peak 110A for 15 seconds. But when I enlarge the capacity - I will have the same charging currents value. So I am in deep sh*t ... :D :( High charge current alarms are usual for me! :(

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