ESS "partly" working

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spithost asked Jul 26, '22

ESS "partly" working

System is a Multiplus II 5000/48 with a BYD B-Box pro 10kWh Lithium set connected to VE.Can on my Cerbo GX with the Can-speed set to high.
I have two PV-sets. One connected through a SmartSolar Charger VE.Can 150/70 connected to the second Can-bus on my Cerbo GX at normal speed. The second PV-set is connected through a BlueSolar Charger MPPT 150/35 rev3 connected to VE-Direct.
The loads are covered by the batteries with both chargers working at top performance and the batteries are charged of course.
That works ok until...... the batteries are at 100%. Then the set connected to VE-Direct keeps working at top performance, covering the loads and bringing the excess to the grid.
But the set connected by VE.Can is switched off, not doing anything anymore:-(
And, as that PV set is normally producing the most power, this is kind of a bummer.... ;-)
Of course at the end of the day, if the set connected to VE-Direct isn't able to cover the loads on it's own, and the batteries are depleted a bit, the VE.Can MPPT kicks in again and start producing again until the sun goes down completely.
I changed an older VE.Can MPPT for the VE-Direct one and then a new menu-item appeared called Networked operation?!
With the VE.Can MPPT it says Group Master and at BMS controlled it says Yes.
With the VE-Direct MPPT it says Slave at Network status, Ext. control & BMS at Mode setting and Yes at BMS controlled.
I'm not sure if these screens have anything to do with the problem, but as the menu-item appeared after changing an OLD VE.Can MPPT for the VE-Direct one, I thought it could have to do with these problems. Before changing the OLD VE.Can MPPT, BOTH MPPT's were shut off when the batteries were full, bringing no power to the grid at all...
Is there one of you who had this problem and/or may have a working solution?

MPPT Controllers ESS VE.Direct VE.Can

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Alexandra ♦ commented · Jul 26, 2022 at 06:38 PM

@Spithost

Is everything up to date firmware wise?

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spithost Alexandra ♦ commented · Jul 27, 2022 at 08:11 AM

yup. The only thing I don't regularly update, is the MultiPlus II itself. The process for this is quite "invasive". The rest I keep updated. So the MPPT's are all updated to the last version and the Cerbo GX updates itself automagically through internet.

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Modifications Space

Node Red Space

Answer 1 · 2022-07-26T18:55:17Z

nickdb answered · Jul 26, 2022 at 06:55 PM

Make sure you haven’t configured smart networking (blueteeth).

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spithost commented · Jul 27, 2022 at 08:12 AM

Ehm.... How/where can I check that?

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nickdb ♦♦ spithost commented · Jul 27, 2022 at 10:42 AM

Make a local blueteeth connection with VC app. Under settings a networking option will appear at the bottom of the list. Just make sure you haven't joined or created any smart networks.

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spithost nickdb ♦♦ commented · Jul 27, 2022 at 06:44 PM

No "smart" networks there. Only the possibility to create one ;-)

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Answer 2 · 2022-07-27T09:06:46Z

nhuillard answered · Jul 27, 2022 at 09:06 AM

I have a new MPPT RS 450, with 2 trackers, which behave the same way. When reducing PV power on battery full, one of the trackers shuts off, then restarts when needed. Since it restarts fast enough in the evening, and apparently does not occur everytime, I didn't investigate.

Obviously, both trackers are connected the same way to the GX device (VE.Direct).

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spithost commented · Jul 27, 2022 at 12:11 PM

So apparently it is a problem that occurs more often. Hope someone knows of an answer ;-)

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nhuillard spithost commented · Jul 27, 2022 at 01:30 PM

Well, this is not a problem for me, since I don't export the surplus to the grid. I guess it's even more like a feature, ie. the idle MPPT tracker is just cooling...

Which brings me to the possibility that one of your tracker is aware that you want to export the surplus, while the other just notices that the battery is full, and stops there.

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nickdb ♦♦ nhuillard commented · Jul 27, 2022 at 01:34 PM

As long as they are both under external control with DVCC enabled their actions will be coordinated. Mppt's aren't perfectly load balanced so if demands are low, one can go to sleep while another supplies the load. There is usually a good a reason if a charger is supposed to be on but isn't. Trick is finding it.

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spithost nickdb ♦♦ commented · Jul 27, 2022 at 05:00 PM

As I understood from ESS, that all connected MPPT's would be "switched" to max output and the MultiPlus II feeding ALL excess power to the grid if the batteries are full. And THAT is the situation I want ;-)

I see this as "unlimited" demand from the grid ;-)

I wouldn't know what reason there could be to switch one MPPT off (not doing anything) when ESS is active?
I have tried with limit feed-in set to 2000W, 3600W and also no limiting, but the MPPT (mostly generating the most PV-power) isn't coming to life. It only switches on again, when the least producing MPPT can't manage the loads anymore :-(
Then it kicks in as long there's sun, and then the system manages the loads from the batteries until the next day.

The BMS signals the MultiPlus II that it doesn't need anymore power by limiting the Charge current to 0, but I don't see how this should effect the output of this particular MPPT as they are supposed to be "under control" of ESS.

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spithost spithost commented · Aug 20, 2022 at 02:28 PM

Today I kept an eye on the system reaching full batteries.

When the batteries reached 100%, the BMU of the BYD's changes the Charge Current Limit to 0A and it is at that exact moment, that the VE.Can-connected MPPT switches off.

The VE-direct-MPPT keeps running happily at full throttle, covering the loads and pushing the excess PV to the grid.
I would like the VE.Can-MPPT do the same and have that one push all of IT'S excess to the grid as well....

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Answer 3 · 2022-08-25T14:58:22Z

Argch... and when you find the culprit, you feel soooooo stupid....:-D

When I asked Victron for some insight in the code of ESS, to maybe discover a bug somewhere (I'm a programmer by profession) they asked me to first install a beta firmware on my Cerbo as there have been some (not publicly available yet) improvements to this part of the code....
Installed the beta but that didn't help :-(

Probably as frustrated as I was, a Victron expert dove into the logs of my system and discovered that there was an "Remote input connector" switching of the VCan-MPPT....

As I'm just an advanced user, and didn't install the system myself, I didn't know my installer had made a wired connection from the BMU of the BYD-batteries to the MPPT's to "turn off" the MPPT's when the BMU tells that it doesn't need anymore current because the batteries are full.

As these kinds of wires are actually meant for combinations of BMU's and MPPT's that DON'T talk to each other by some communication-bus, these are kind off "overkill" in my situation.

Both the BMU and the MPPT's (one through VCan and one through VE-direct) are talking to the Cerbo and MultiPlus II. So when the batteries are full, the MPPT's are switched off through these busses aa well.

So when I cut this wire between the BMU and the VCan-MPPT and short circuited this wire (the relay in the BMU is a NC-type) the VCan-MPPT kept on working full-throttle when the batteries were at a 100% :-D

At that same moment, the current to the batteries dropped (regulated with ESS by probably the Cerbo in combination with the MultiPlus II) and the battery-voltage stabilized.
ESS now keeps the batteries at 100% by checking the batteries and sometimes pushing some Watt's to them, covering the loads and pushing the rest to shore.

So..... I'm a happy camper now, pushing about 1000W or so to shore at this sunny weather with both MPPT's working full-throttle, making my electric bill a bit lower.
And with the soaring energy-prices, because of that stupid war, every kWh counts ;-)

So if you have a comparable problem as I had (MPPT's switching off at full batteries and under ESS), check if there's a wired connection between BMU and the MPPT's that may be obsolete and overruling the bus-communication...

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