Let me share my setup and I’m open for discussion and improvements:
3x Multi 2 / 3000 / 48V / 230V in parallel with 2 DIY batteries (48V setup; 16x280Ah and 16x304Ah plus 2 JK BMS) and 1 Shunt plus 10 MPPT (based on my roof) with EM24 and Cerbo GX.
These setup runs in parallel of my good old self-pv (1,1kwp) and in parellel of my existing electrical installation. One more - I don’t feed my energy back (only self consumption).
System works perfect but still room for improvment (I guess).
I’m not really sure about the voltages I set in the Victron and/or in the JK BMS. Especially the “last charging hour” and the peak of the voltage (up to 56V) isn’t that good for the batteries.
What is recommanded to avoid a “stress” during charging of my batteries? Victron? JK BMS settings?
The “new” Energy Meter from Victron instead of EM24 (I bought it already) to get a better reaction time of the setup?
New FW? I’m still on 551 and also on an old version on the Cerbo GX.
One more - it’s based on my needs and given old setup but I’m open for some optimizations. I’m not the guy who’s looking for the last kwh but I want to reduce or midigate mid/long term issues in the setup especially with my batteries.
Your setup sounds good to me. Don’t see any points to be worried about. The EM24 might be not the fastest, but still very good. I would assume you will see not difference between an EM24 and the EM540. The delay in the regulation is mostly done by the Multiplus itself.
Regarding your battery charging settings, - a good and common value for the absorbtion voltage is 55,2V for a 16S cell pack. So you have 3,45V per cell. But the 56V (3,5V per cell) is still good within the cell datasheet specification.
Interessting for us would be how high is your max charging current. For this parallel 280Ah+304Ah I would not go over ~150A (depending on your cables as well).
Regarding the firmware, - I’m also not updating the system every time a new firmware is available. I do a MP2 update once a year or so. The Venus OS maybe 2 times a year. In general, when the system is running well, and I don’t have any issues, then I do not touch it.
Especially the voltage of my batteries is on my list . Not 100% sure how and where I have to change that (ok - BMS and Multis I guess ) and I have to check YT, Forums like this and also have to document my current setup.
Charging current is not more than 150 Amps in total. Based on the cables (50mm2), cable lengths (3meters), internal resistance, it’s quite even. Never ever had some big differences between both battery packs (hopefully also in the future).
The good (and bad) thing with my setup and based on the roof, I use 3 directions (East, South and West). Based on this, I don’t have such a peak as I know it from other users (only one direction = South). It’s a smoother charging curve (starts at e.g. 6am with a part of my modules, peak during noon and a smooth phase out during the afternoon except). And to avoid high charging current, I can use the heating element of my hot water tank to reduce the current (and heating up the water).
I’m currently in preparation of the 3rd battery pack (prices are very low) - similar setup.
About FW - ok, so do not touch still a good approach!
One more - I’m still struggeling with Venos OS on a Raspberry PI. As far as I know, it’s the better choice in case of adding external sensors, etc. but should also work with Home Assistant and the VRM plugin, right?
About the batteries - Raspberry PI Gen 3 in place and connected via Bluetooth (“ok setup” not perfect) with the JK BMS to get more insights about the status of the batteries. It’s also connect via Home Assistant.
I can recommend you the YT channel from Andy called Offgrid Garage. He tested very intensive all the battery parameters over years and (I would say) is the god of batteries. The 3,45V per cell is also his recommendation.
Charging from different orientations is very good instead of peaks like you already said.
I did not get your point regarding the RasPi. It has some advantages, but especially regarding sensors it might be worse choise. It depends on the sensors you want to connect. The CerboGX has various inputs that are especially made for sensors, so check what you want to have.
I have a RasPi4 running from the beginning, so over 3 years now without any issues so far, but can’t help you with Home Assistent. The bluetooth connection of the JK BMS is not that stable, I would change this to a cable version in the future.
The limits in the BMS are the max. limits (the so called “last line of defence”) so the BMS should only disconnect the battery in case of real cell over- or undervoltage or temperature. The charging and discharging parameters should never overlap with the settings in the BMS. So set the MPPTs and the MP2 according to e.g. Andy’s recommendation, and the BMS should be wider.
Thanks for the hint I know him but as you already said, I should review his settings again.
About Raspi - I was thinking in the direction of additional temperature sensors in my batteries, close to the Multis, etc. for faster “reaction time” in case of issues. Otherwise - I can use Home Assistant.
Can you share more insights about your Raspi config plus the module you are using for the connection with your BMS?
Well, the most BMS already has temperature sensors that allow to measure 2 up to 4 positions in the battery package. You just need to display this somehow in the victron system.
I have an old JK BMS (not the so called inverter BMS) and use the RS485 communication port with a RS485<->USB adpater to connect it to my RasPi. On the RasPi I have running the SerialBattery script from github. This brings me all the values like charing/discharging currents, voltage, cell voltages and temperatures. This works very nice without any problems.
In your case, as you have more batteries, you will need the so called “battery aggregator” script, that will combine all the batteries to “one” big battery. I don’t know the details, but there are a lot installations running with this very well.
A good and easy way to display more temperatures is to use the Ruuvi Tag sensors. They work over bluetooth and can be directly integrated into the VenusOS. Some people use this to display the batterie temperature. You can use several of them at once. But they are not too cheap.
. Not 100% sure how and where I have to change that (ok - BMS and Multis I guess 
The 3,45V per cell is also his recommendation.