I would use node red- switch it to keep batteries charged using soc switching and back to optimised when the desired soc is reached off grid charging.
Leave it disabled in the ve config.
Sorry, I do not understand how you prevent charging with this.
As far as I understand:
- Keep battery charged still charges the Battery until 100%SOC
- Optimized also charges the battery
- There is no maximum SOC I can set
- I can set minimum SOC to prevent discharging when AC-IN ist connected
Why to change between āKeep chargedā and āOptimizedā?
Do you have any modded or custom controls or code in your system?
Since you want zero current in some cases and current in others maybe manipulate the charge current assistant. (Using a relay from the GX)
The only other way is through d bus mqtt or modbus.
I only want zero load current from AC-IN. MPPTs shall work.
Or disable the internal charger of multiplus which seems to be only possible via VEConfigure,
You mean to switch off AC-IN to prevent charging from AC-IN?
This is also what I am considering. I just do not like that switching the relays on and of may reduce lifetime of the relays.
On the other hand it may be better just to set grid current limit to 0.
Thanks for pointing me to the VeConfigure assistants. I will look into it.
You can configure the Multi with a Charge Current assistant.
With that you can dynamically change the charge current based on a variable voltage on an Aux/Temp input. Switching between two fixed values (0 and max for example) can be done with a (solid state) relay, for instance one on the GX that you drive from Node Red.
The option to actually disable the charger (instead of setting 0A) is there too.
Hmm. I seem not to understand this option,
I do not want to restrict DC charge. Instead I want to switch the internal AC charger on or off.
The assistant says that the internal charger will be only disabled when DC charge ist set to zero.
Or did I get this wrong?
You read that right. Setting the charge current to 0A will limit the internal charger to approximately 0A (due to measurement/rounding errors). Checking the box in the next window will actually turn the internal charger off if itās set to 0A - just as if you would disable the charger in the āChargerā tab.
What works best for you (limit the internal charger to 0A or completely disable it) is something you need to test to see what works best for you.
The assistant gives you the option to switch between settings (using an external switch or relay) without having to use VE Configure to make the change.
Now that Iām thinking of it: with a PV inverter on AC Out maybe itās not a good idea to disable the internal charger of the Multi.
Scenario: sunny day, the grid is out but PV inverter and MPPT/batteries are supplying power to your loads.
Then you turn a large consumer off.
The PV inverter, that might be running at full power, canāt throttle down immediately so for a short while the excess PV energy needs to go somewhere.
If the Multiās internal charger is disabled and this happens, things go boom.
@herzigwi : what are you actually trying to accomplish ?
You can set the assistant to have zero current.
Open ve config in demo mode and run through the assistant yourself.
Thanks for all your input.
Happy to learn with you.
I had an interesting thing happen today. The system began charging today from ac sources even with the charger disabled. Exactly as you experienced- regardless of ess battery mode chosen. I am not sure what changed from the other day when i took a few minutes to play with it.
How proficient are you with modbus and node red?
There is an old forum thread i was looking at with some options. I think with newer Node red it may be easier. If i do get time will look into it more.
I remember that Iāve read somewhere that there is a āforced chargingā with low currents when SOC stays too much below a certain levelā¦
Maybe those conditions were met or I am talking nonsense?
There is a sustain charge yes.
Our batteries always charge to 100% during the day. We have way too unstable power and solar during rain season to gamble with not doing so.
No, it didnāt hit that point in the system was still way above at 62% soc and above all the trigger voltage. So it an interesting thing.
Thanks.
The problem with maximum charge power is that it will also reduce MPPT charging. When sun comes up you do not know how to set the charge power. Too low and the MPPT reduces charge. To high and I charge via AC-IN too much.
What I have programmed and tested with Node-Red in the last two days is the following.
Adjust node āVE.BUS System Control/Multiplusā to set āActive input current limit (A)ā:
- LOW If the external PV inverter (value via modbus/TCP) should be restricted to load the Multiplus battery.
- HIGH if I sun is down and I want the Multplus to discharge
āActive input current limit (A)ā restricts the current of multiplus on on AC-IN.
LOW can be 0A or 1A if there are loads on AC-OUT and multiplus battery SOC is minumum. HIGH is for example 16A or 32A.
If I set to 0A the internal charger is no longer in use for AC-IN. But the MPPTs can charge as much as possible. Setting so some higher value like for example 1A allows to use some of the external PV inverters load.
Today sun is shining. Seems that it is working as expected.
Thanks for the insights and help.
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