This is my thinking to, the BMS controls when the battery is shut off etc, so the settings in the rest of the system has to be based on those.
I'm wondering how the cut off settings in the ESS work, presumably it will turn off the DC side, but still pass through the grid if these conditions are met.
I'm putting a spreadsheet of all the settings together, then I can easily look up and see what needs matching up.
PS. Be interesting to hear what Victron come back with.
Exactly, if you look at the Pylontech they setup these in the ESS (and including Other Battery Brands as well..) basically I read on the Victron Forum as well just to Flat-Curve the Charge curve in the Dynamic Cutoff Voltages and basically let the BMS do the work. I will post below a snapshot from Pylontech.
Wifey was doing the Dinner last night, so had 1 or 2 hob's induction rings on, plus the Microwave and the Kettle. I looked at the VRM portal and I could see it spike up quite high on the load.. what happened was and based on the Cutoff Voltages etc... then the Multi stopped inverting (Battery was about 55% @ about 52/53V.. cannot remember exactly... but with the high load the voltage would drop while supplying the current). At this stage then the DNO/Grid supply was used untill I modified the Cutoff Voltages - so yes it will turn off the DC Only, this is my understanding as well.
What you can do, download VE.Config then go to the VRM Portal.. then to Devices and then you can Download the config off the Quatro/Multi and amend it off-line with VE.Config and then Upload this.. I did this and changed the 0.005C & 0.25C by 1V.. not much.. WELL all kicked back in and I watched the Inverter do it's stuff.. I also saw how much current was been drained from the battery ( I also have a Monitor on the JK BMS as well but mine is the 4" version).. Current discharge started around 20A and then slowly started to rise up to about 85A.. you should have heard the hum from the transformer .. beautiful.... it then all dropped down to about 45A afterwards.. but not long after..
This is why I started to review the settings and really ask the question.. do we really need to have the ESS setup this way as the way I see it.. if your battery pack is managed by the BMS and is roughly/about 53V @ about 50% then with these settings in the ESS and with a sudden load then the inverter will stop inverting ... it won't power down it will just stop inverting as I saw last night.
Snapshot From Victron with ref to Pylontech:
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5.2 Charge Settings
Charger tab
Parameter | Setting |
---|
Battery type | Lithium |
Charge curve | Fixed |
Absorption voltage | 52.0 V |
Float voltage | 51.0 V |
Absorption time | 1 Hr |
Note: make sure to double check the float voltage after completing Assistants, and if necessary set it back to 51.0 V.
Note For off-grid use: ignore the 'bms assistant required' warning.
5.3 Inverter Settings
In the Inverter tab of VEConfigure
VEConfigure Inverter Parameter | Setting |
---|
DC input low shut-down | 44V |
DC input low restart | 48V |
DC input low pre-alarm* | 48V |
* The pre-alarm setting is dependant on your preference and on site specific requirements. You may wish for this to be activated earlier in an off grid situation to allow time to start a backup generator.
ESS System Settings
If you are using the battery as part of a
grid connected ESS system, please review the
ESS Quickstart guide and
Design and Installation Manual.
The settings that are specific to the Pylontech battery in the VEConfigure ESS Assistant are below:
Select the externally managed Lithium battery option
ESS Parameter | Settings |
---|
Sustain voltage. | 48V |
Dynamic cut-off values | set all values to 46V. |
Restart offset: | 1.2V (Default) |