The time out value i am not defining using modbus. There was a setting for timeout value in the sbs5 battery invertor configuration webpage
How to make your SMA SBS 6.0 Battery Storage Inverter Dormant using the modbus interface and Home Assistant.
I have an Electric Vehicle (EV) which I charge at night using the cheap rate electricity.
Whilst charging my EV I do not want the battery storage system to discharge into my EV, I just want to use the cheap off-peak electricity from the grid.
It is possible to use the “performance profile” on the battery storage inverter to do this but this only allows for fixed times and I needed to make the battery storage inverter dormant WHENEVER I charged my EV so the performance profile was not
an option for me.
I asked SMA for support and received some help that pointed me in the right direction but sadly without enough detail to implement a working solution.
This is what I did: -
First make sure your battery storage inverter has the following parameters set: -
Active/Reactive power measurement: inverter (Not SMA Grid Power Measurement)
Active/Reactive power setpoint timeout: 1800 seconds. {The default value is 30 mins and 60 mins is the most)
The following modbus registers are used: -
44427 is used to enable/disable the communication of the power setpoint (unsigned 32 bit integer).
Enable = 802
Disable = 803
44425 is used for the Power Setpoint value in Watts (signed 32 bit integer)
A positive value means discharge and a negative value means charge the battery.
In Summary to set the battery storage inverter to a dormant state: -
Write 802 to register 44427
Wait 1 second
Write 0 to register 44425
The above command times out after an hour which is typically not enough to charge an EV. I used a Home Assistant script with a WHILE loop to resend the above commands to the inverter every 45 minutes whilst the EV was charging so that longer EV charge times could be supported.
To resume normal operation of the battery storage inverter: -
Write 803 to register 44427
In addition to making the battery storage inverter dormant it is also possible to
force the battery to charge or discharge at a fixed rate.
A modbus register is 16 bits long so two registers are used to represent a 32 bit number.
When editing your Home Assistant script use the following: -
[0,0] for zero Watts
[0,500] to make the battery DISCHARGE at a fixed value of 500Watts
Please note that in Home Assistant setting the value of a signed 32 bit number to
a negative value is as follows for modbus.
[65535,64535] to make the battery CHARGE at a fixed value of 1000Watts.
[65535,63535] to make the battery CHARGE at a fixed value of 2000Watts.
I hope this helps people facing a similar problem…
Steve
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Hi,
On 27/05/'24 a firmware update has occured (2.14.13.R) on my SBS5.0-10.
Since no Modbuscommu. possible.
Any idea when the new update will be released?
Thanks in advance