My config.
I have succesfully connected my JK BMS to my cerbo.
I use 2P16S LFP batteries, victron smartshunt, cerbo and multiplus ii.
My PV is AC connected to the multiplus out.
I use dynsmic ESS.
I plan to start using DVCC to have the JK BMS controll the MP charger.
I have two questions, hopefully someone can help me.
I have it like this and it works a treat.
I recommend updating BMS to newest firmware as it solves lots of stuff.
Using BMS for charging control is best idea. If you set up parameters in BMS right.
I have Floating mode enabled and Take battery up to 55,2V for one hour. Then it goes down to 53,6V. Also i also have 2x16S battery and each has its own BMS. It is much better that way because you have per cell monitoring.
I have it set up like this. And I highly recommend to calibrate the JK BMS current, in both charge and discharge situations. The SOC will behave much better.
@jkoljo how can you calibrate the current in the JK BMS? I notice a big difference between the current value in the BMS and Smart shunt. The funny thing is that there is only a big different when discharging! At 35A or 55A the values are more or less the same.
Would like to know now to calibrate this. Thanks.
You need the JK BMS app on your phone.
My BMS was about 15A off (too much) when discharging at 70A actual, and 5A off (too much) when charging at 70A actual. After calibration it matches my DC current clamp with max error of about 1A.
This probably is impossible.
Which JK BMS is used? I have the JK Inverter BMS PB2A16S20P hardware version V15A.
Before updating to the last firmware the SOC alwaays was reported too high. After 2 weeks without reaching balancing voltage the BMS reported 50% SOC at 49 V. At 49 V the real SOC is about 10%.
With the new firmware this problem should be solved. And indeed, the reported SOC now seems quite accurate, perhaps even a little to low. But then a I noticed that JK achieved this by using a dirty trick: while - after calibration - the charging current is measured quite accurately, discharging current is reported (and probably used for SOC calculation) with a huge factor. I.e. the BMS reported 18 A discharge, but a reliable independent ampmeter says that there was only 12 A discharge.
Sorry to have to say that: you can’t rely on current and SOC data reported from the JK Inverter BMS. Calibration does not help.
Not sure how your BMS is different from mine, but I updated to the latest FW maybe a month ago. I have the 200A JK inverter BMS. I initially only calibrated during charging, and that did not help much. Calibrating during discharging as well helped.
It helped much in my case. Charging currents are measured very accurately, with only about 1% deviation compared to an independent measuring device.
Well, yes, but as you said the SOC estimation will still be off because discharge is inaccurate. Discharge and thus also SOC estimation became accurate with the extra calibration during discharging.
I think JK is using two different sets of calibrations, one for discharge and one for charge. What’s confusing is that you enter the calibration value by using the same field.
I also use DVCC and my settings are, in general, the same as shown above. The difference is, perhaps, that I set the maximum charge Amps from a flow in Node RED. Based on solar forecast and the time of the day. This way the battery can warm up slowly, and I don”t stress my batteries all too much. And no. I don’t mind if it takes longer to charge them up to 100%.
In all your screenshots above the SVS Shared Voltage Sense is activated, but SCS Shared Current Sense is sometimes activated, sometimes not. Why?
Because they are different users with different setups… 
Ok, in other words: when does it make sense to activate SCS and when not?
Yes thanks, I know that. And according to this documentation, SCS makes no sense when using the JK BMS as the controlling BMS. That’s why I wondered why it is still activated in some cases.
Sometimes I saw cases where users have enabled it, because “if it’s there, why not use it”… 
And because the manual is that thing that collects dust and remembered only if a problem appears.
If remembered were was put… 
Having SCS enabled (by default) in the settings doesn’t mean that it is actually being used. Just look at “SCS status”. If any of the seven external controls is being active, then this feature will be disabled anyway. Disabling it in this condition is then just a redundant procedure.
Also. With a BMV or SmartShunt, both SVS and SCS should be on. Recommended by Victron. Even with a JK-BMS in your (DIY) battery.
