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Hi, is there a possibility to limit the amount of discharge from the battery (e.g.40A) without limiting the inverterpower from the mppts? I want full invert power when the sun is shining and reduced when the battery provide power. My Multiplus II 48/5000/70 can draw to much power from the batteries. When I limit the Multiplus it is also limiting the inverterpower from the mppts which would not be required. Thanks
There is not a direct setting for setting the battery discharge, but rather a workaround. You can limit the inverter power so it does not draw from the battery. Note this will only work if you are connected to grid though.
So in your case you would limit your inverter to 48v (or whatever you battery voltage is nominally) x 40A, so 1920Watts. Then if it cannot make the power from the mppts, it will draw from the grid rather than battery.
If you are running ess this works well. Keep your grid set point down, then ess will manage it dynamically.
If you are inverting, then unfortunately the power must come from somewhere. If you are not producing then the battery is the source.
When the MPPT can't supply those 1920W, the inverter will still use the battery for the power difference.
He wants something else.
You would have to dynamically adjust that inverting power limit, based on momentary MPPT power.
The other way is to tell ess to keep batteries charged or set minimum SOC to 95%, then whatever you are not producing on solar comes from the grid. Then it may pull a few watts every now and then, but not load the battery at all really for the higher loads.
Unfortunately even the inverters that have a specific setting for the discharge limits I have seen do not actually adhere to the setting as expected. The simple fact is if you are using the power it must come from somewhere the best you can do is tell the inverter which sources to prioritize.
@skykay @Alexandra I wrote a script to dynamically adapt the grid setpoint in order to reduce load on the batteries. Whenever the load in batteries gets > 50W i raise the setpoint. This allows PV to step in. This assumes you are connected to grid.
https://community.victronenergy.com/questions/113114/software-attenuation-for-home-excess-pv-charging-o.html
Are there some news around this topic? I am looking for exact the same Feature.
I am using my solar system with grid connection but without sending energy to the grid. (Victron ESS setup) My battery is small so i have to limit the maximum inverter power. In winter times this is not a problem but on a sunny day, my PV is generating more power than the limit. So i am not able to use this additional power because of the inverter limit. In that case the MPPT have to reduce the amount of PV power and this is not my prefered solution.
I did not have a look at the solution of @Bogdan Nedelcu but it would be great to have an additional parameter in the config. My Cerbo showing exactly where the power comes from, so all the relevant data sould be still there.
Cheers
bb
Ess pretty much does what you are wanting to do.
It uses solar as much as possible for loads. Draws the power set the grid set point. With keep batteries charged setting it then does not have heavy loads on it to draw it right down, but would rather draw from grid when cloud cover comes over.
Sorry, but i can not follow you. And i did not understand what kind of information will be shown in your image. Do you have set a limit to your inverter?
Maybe my current setup is completly wrong: What i have to do to save my battery from overload? Should i limit my inverter?
Here is an example with some numbers, maybe it will be easier for my to understand:
I limit the inverter to 1000W to save the battery.
Now i have a load of 3000W, PV would be able to produce 4000W i would expect something like this:
- Inverter only generates 1000W because of the limit
- PV will be capped by 1000W, because of full battery, and no input to the grid
Is this correct?
Hi, there were no infos for a while and i am not sure the reason for it. Maybe my example doesn´t make sense at all or is unclear? Is there no solution for my problem? Maybe there is no problem and my config is completly wrong.
It would be great to give some answers or some keyword to search for. Currently i am completly lost with this topic.
Thx
bb
I apologise I did not see your reply. using the @username helps with notifications.
There is not way to limit what comes out of the battery if your loads need it and PV production is down, there is not grid, it will pull from the battery.
If you have stable grid, then you can set the system to keep the batteries charged (so it does not draw from them except when power assisting for a few seconds if you starting up a big load. (this is user controlled loading so it is up to you how you use your system)
If your PV production is high enough to cover your loads (as shown by the picture I posted then nothing comes out of the battery and nothing comes out of the grid.) The battery is shown as idle.
Here is an example with some numbers, maybe it will be easier for my to understand:
I limit the inverter to 1000W to save the battery.
This will work. It will pull from the grid what is over that (with posibly small amounts of assist from the battery depending on loads starting up)
Now i have a load of 3000W, PV would be able to produce 4000W i would expect something like this:
- Inverter only generates 1000W because of the limit
- PV will be capped by 1000W, because of full battery, and no input to the grid
Is this correct?
Yes you are correct.
In all cases the MPPTS will only produce what is demanded by the system, up to the maximum of PV in the working conditions or the limit you have set.
Thank you for your response. Hopefullly now you get informed. I am not very familiar with using boards like this.
Ok, so for me the only solution to prevent battery from overload is to change the inverter limit by load. I will have a look into the victron api, maybe this is possible.
