Quick question, the Battery SOC Is 60%, there is enough solar power and charging from grid is also possible (at low energy prices), what could cause the fact the Multi RS Solar stays in Float mode? Which settings should I check?
A little bit more info about the system will be nice…
Which battery? Does it have a BMS?
Do you have a Cerbo-like device in the system?
If yes, is the battery connected to Cerbo? Is the DVCC enabled?
If not, which are the set voltages for bulk, absorption, float in the Multi RS?
Etc…
Otherwise is just like this below. Hope you won’t mind… 
As well as the list above, what is the actual battery voltage and are the cells balanced. SOC is a calculation and is sometimes wrong, voltage is the key.
Vallid comments of course, I need to provide more details indeed. I was still in the office had had some challenges getting all the details.
Voltage of the battery: 53.43 V
SOC Battery 67%
Currently charging with 117Watt and 2A.
LifePO4 MB31 314Ah battteries, 16x
JK BMS is connected via the CAN bus to the Cerbo.
Cerbo is controlling the system. DESS is enabled and was working good for the past month.
DVCC, I’m not aware of this functionality so it is disabled.
Other battery charging settings will be provided in an hour or so.
DVCC info here: 11. DVCC - Distributed Voltage and Current Control
If DVCC is disabled, then the chain BMS → Cerbo → MultiRS is not controlling the charging.
Therefore the values set into the battery section of the MultiRS are taken into account.
The current 53.43V is indeed pretty close with the 53.6V set at Float voltage.
One observation, your storage voltage setting is higher than float, it should be lower. However, I do not expect this to be the issue, but you should set it to the same value as float.
A key parameter not shown is the rebulk voltage offset, the battery voltage has to drop this much below float to start a new bulk cycle, has it dropped below this.
From the manual
- Re-bulk voltage offset: Set the voltage offset that will be used over the float voltage setting that will determine the threshold that the charge cycle will restart.For example, with a Re-bulk voltage offset off 0.4V and a float voltage setting of 54.0 V, the voltage threshold that will be used to restart the charge cycle will be 53.6 V. In other words, if the battery voltage drops below 53.6 V for one minute, the charge cycle will restart.
WIth the sentence:
If DVCC is disabled, then the chain BMS → Cerbo → MultiRS is not controlling the charging.
Do you mean the MultiRS is controlling the charging of the batteries? I assume so, that is where I configured the battery parameters as per screenshot above.
My current battery config settings:
And I just noticed there is a firmware update for the Multi RS Plus, so I changed now to version 1.22.
Yes.
When DVCC is not enabled, then the inverter/charger - in your case the Multi RS - is controlling the charging.
But…
It’s better to let the BMS to tell the Multi RS which are the charging parameters.
Therefore, it could be better to study the DVCC docs and then enable it.
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SO on your settings, the charger will only go back into bulk if either
- if the battery voltage drops below 53.0V (53.6 - 0.6 float - rebulk offset) so you will need to check your history to see if this has happened or not.
- 7 days have elapsed since the previous absorption (repeated absorption), how long ago was your last absorption.
If you want a more frequent absorption then reduce the rebulk offset and/or the repeated absorption period.
Thanks @pwfarnell for your suggestion. I recently changed the minimum SOC percentage in the DEESS config from 30% to 15%. This could be the reason why maybe the voltage dropped below 53.0V. The 4 days history pictures shows that the battery voltages dropped under the 53.0V multiple times.
Seems like the float issue is not occurring anymore, not sure if I can say it is solved as I’m having some DESS challenges right now. See topic