I’ve started to build my ESS system consisting of Multiplus-II, Cerbo GX, and two Pytes ebox 48100R yesterday. I have a PV system connected to AC-In (parallel installation).
I updated the Multiplus and Cerbo to the newest version.
So far, everything seems to work, BUT:
When I set the Multiplus to “Charge only” mode, it does exactly charge only once. When PV surplus stops, the Multiplus stops charging (fine!), but when there is PV surplus again, it’s feeded to the grid. When I set the Multiplus to “on”, everything works as expected, and charging starts as soon as there is enough PV power.
Furthermore, but I don’t know if its linked to this issue, the Cerbo GUI V2 webinterface shows “external control” as Multiplus status, although ESS is set to “optimized with battery life”…
Thank you for your answer.
I would expect that the system acts exactly like in “on” mode, just without the “inverter” part: Charging, when there is excess-PV, idling, when there is no feed to the grid. For me, it’s not clearly understandable why it doesn’t (or does it only once) charge in charger mode when there is enough energy…
In an ESS system, how i have understood it, the ‘charger mode’ is keep batteries charged setting in ESS and Charger only is more for other systems where depth of discharge cannot be controlled.
Possibly since you are not feeding back through the inverter things are a little different to expected.
“keep batteries charged” in ESS does something different for me: It starts charging immediatly from the grid to the desired SOC. That makes some sense for me.
In my opinion, setting anything for the Multiplus shouldn’t affect the behaviour of the ESS. So, when setting the Multiplus to “charge only”, the system should exactly behave the same as in “on”, just without the inverter part. I would expect that when setting to “inverter only”, the ESS works identically like in “on”, but just for the inverter part. In my opinion, any other behaviours are hard to understand and don’t make sense…
The point of ESS is to mix grid and solar while power assisting loads and reserving a desired amount of battery in the on state. See the introduction in the manual.
The other option is to use min soc at 100%. That also changes the behaviour from keep batteries charged.
Switching it to charger only is for systems that are non ess ir not allowed ess. In this state it still allows power to pass through and solar to assist loads without discharge on the battery.
By switching to charger only with a system designed to self manage is messing with the program.
The point of ESS is to mix grid and solar while power assisting loads and reserving a desired amount of battery in the on state.
Yes, that’s clear and that’s the goal. I’m still in testing phase and for me it was not obvious, that Multiplus-Settings and ESS are connected in this way. My intention was to fully charge the batteries for the first time, so the BMS can do it’s things.
The other option is to use min soc at 100%. That also changes the behaviour from keep batteries charged.
That’s maybe the solution I’m looking for. Good idea, I will test this. Thank you
The other option is to use min soc at 100%. That also changes the behaviour from keep batteries charged.
That’s maybe the solution I’m looking for. Good idea, I will test this. Thank you
Answering to myself: No, at least not exactly. When using this approach, ESS starts charging the battery from grid as soon as the desired SOC is at least 5% bigger than the actual SOC (“recharge” functionality in ESS manual 4.3.10/“auto-recharge” in ESS manual 10.12 - why isn’t it possible to deactivate this behaviour?).
Possible, running ESS in “mode 2” may be the solution. I still have to work on this. For me, switching from mode 1 to mode 2 is still not completely clear, as according to the manual (1.1 off ESS mode manual) the “grid power setpoint” isn’t available in mode 1 - but I can see it in Cerbo - maybe I’m already in mode 2?
But I’ve found the solution for my “problem”: Instead of changing the Multplus modes, I can just set “limit inverter power” in the ESS menu to 0 for a “charging only” mode. That does what I want (and that’s one of the parameter Victron mentions when they speak about mode 2).
For a “inverter only” mode the setting “limit charge current” in the DVCC menu does the thing. So I can adjust exactly the parameter I wanted.
I have often heard complaints that this limits solar production and charging as well. Have you experienced that?
Have not had enough PV power yet, but I don’t know how this even could affect AC coupled inverters. But we will see, if there is anything I will update here
