LiTime BMS

[calledit]

Is your feature request related to a problem? Please describe.

Hi I built a project to request and interpret data from the LiTime BMS:

https://github.com/calledit/LiTime_BMS_bluetooth

I don't have that much experience with venus OS. But would be nice if the LiTime BMS was possible to use with venus OS.

This is basically a request for someone to port that project so it can be used with Venus OS.

The LiTime_BMS_bluetooth system is super simple. There are more or less just 4 parts:

• Connect to the BMS using BLE.
• Send the command: commands.query_battery_status
• Wait for a notification from the BMS then calls the function interpret_data()
• Sleep a while then send the query_battery_status command again and repeat.

Describe the solution you'd like

The solution I would like is if someone with experience with Venus OS and this project could initiate this. It would be nice if someone did the boiler plate stuff. The project does have a bluetooth low energy BMS already tried to look at that but it was a bit more complicated compared to how the LiTime protocol works.

Describe alternatives you've considered

Possible alterantive is that I do it myself from the start but it would take much longer for me since I would need to learn how this project is setup.

Additional context

No response

[mr-manuel]

See https://mr-manuel.github.io/venus-os_dbus-serialbattery/general/supported-bms#addrequest-new-bms.

[mr-manuel]

Did you check the template? If yes and you did not understand it, I will update it to be more clear.

Best would be, if you take the template and start from there

Capacity is Ah, SOC is %.

[calledit]

Yes I checked the template, I understand it but it lacks many variables.

The template only contains 3 variables: (if you exclude the settings)

voltage, current, soc = unpack_from(">hxxhh", soc_data)
        self.voltage = voltage / 10
        self.current = current / -10
        self.soc = soc / 10

And as I stated I have the 16+ variables that I listed. Without proper descriptions of each variable it will be hard to know what variable does what.

The battery.py file has more variables (some I understand should be filled out some should not) the best place I could find with verbal descriptions of the variables is the feature page. But you sort of have to guess what feature correspond to what variable. https://mr-manuel.github.io/venus-os_dbus-serialbattery/general/features/

Variables as listed in the battery.py file.

self.voltage: float = None
        self.current: float = None
        self.current_avg: float = None
        self.current_avg_lst: list = []
        self.current_corrected: float = None
        self.current_external: float = None
        self.capacity_remain: float = None
        self.capacity: float = None
        self.cycles: float = None
        self.total_ah_drawn: float = None
        self.production = None
        self.protection = Protection()
        self.version = None
        self.time_to_soc_update: int = 0
        self.temp_sensors: int = None
        self.temp1: float = None
        self.temp2: float = None
        self.temp3: float = None
        self.temp4: float = None
        self.temp_mos: float = None
        self.cells: List[Cell] = []
        self.control_voltage: float = None
        self.soc_reset_requested: bool = False
        self.soc_reset_last_reached: int = 0  # save state to preserve on restart
        self.soc_reset_battery_voltage: int = None
        self.max_battery_voltage: float = None
        self.min_battery_voltage: float = None
        self.allow_max_voltage: bool = True  # save state to preserve on restart
        self.max_voltage_start_time: int = None  # save state to preserve on restart
        self.transition_start_time: int = None
        self.charge_mode: str = None
        self.charge_mode_debug: str = ""
        self.charge_mode_debug_float: str = ""
        self.charge_mode_debug_bulk: str = ""
        self.charge_limitation: str = None
        self.discharge_limitation: str = None
        self.linear_cvl_last_set: int = 0
        self.linear_ccl_last_set: int = 0
        self.linear_dcl_last_set: int = 0
        # list of available callbacks, in order to display the buttons in the GUI
        self.available_callbacks: List[str] = []

Would be great if the template was expanded so that it documents all variables that could/should be filled out. Which ones are required which are not and so on. If they are expected to be floats or strings and so on. It would make things allot easier.

[mr-manuel]

I reworked a great part of the code today and documented it well. I also remade the battery_template.py. If there are still questions open let me know.

[calledit]

Nice work! Will make it allot easier!

First a question:
What should I do with values that are required like self.max_battery_charge_current or self.max_battery_discharge_current which the LiTime BMS does not repport?

I could fill up the value for my specific battery but that is not a very good solution if other people want to use this and have different batteries.

Then:
I did notice that this line is probably placed in the wrong function seams like it belongs to def get_settings(self)

And after scrolling through the above mentioned init function it seams like self.total_ah_drawn and self.capacity_remain is missing.

[mr-manuel]

I changed another ton of code and added a History() class. The new code should answer all your questions.

[traiannicolau]

I am also very interested on this, but I have 0 coding knowledge. How can I make this work? I have a raspberry pi zero w2 and 2 litime 12v 100ah group 24 batteries. Thanks!