Offgridtec LiFePo4 Smart-Pro

[patman15]

Hi @fl4p,
I have implemented a working addition to your repository, so I can readout the Offgridtec LiFePo4 Smart-Pro series of batteries. Unfortunately, I have no idea which BMS is used inside the battery (and I do not want to disassemble it) and I also do not know how to figure it out. Nevertheless, readout works, but the data is scrambled by some key derived from the serial number.
Long story short, in case you are interested, I can spend some more hours to figure out how this is done so my implementation can be used with any battery and not only mine.

Btw. I also found a few minor issues in the main class (BtBms) in case you want some more thoughts. :)

[fl4p]

Hi @patman15 ,
definitely interested in adding this to batmon.
Also let me know what you found in BtBms

Cheers
Fabian

[patman15]

Hi @fl4p,

definitely interested in adding this to batmon.

Ok, I will take a bit of time, I need to figure out how the general algorithm for the data scambling works. :-\

Also let me know what you found in BtBms

BtBms: Shouldn't that class by default read the BT device info? That could give all devices a unique name and probably some additional information.

For the class BmsSample I have troubles with the capacity/SoC calculations together with my BMS. I'm not sure how the different parameters charge, capacity, cycle_capacity are defined by you. In the end, my BMS delivers a SoC, a factory capacity (what is written on the battery) and a current charge in Ah.
If I provide capacity (factory) and charge (current contained energy), the SoC in percent is "wrong" as it is calculated against the factory capacity and not the cycle_capacity (which I assume it the currently available full charge value which is lower than the factory capacity). see also https://www.biologic.net/topics/battery-states-state-of-charge-soc-state-of-health-soh/
If you look at

batmon-ha/bmslib/bms.py

Lines 54 to 55 in 01fabc0

	if capacity > 0 and (math.isnan(soc) or (isinstance(soc, int) and charge > 0)):
	soc = round(charge / capacity * 100, 2)

I guess the line should read
if capacity > 0 and ((math.isnan(soc) or isinstance(soc, int)) and charge > 0): (note the brackets)
as otherwise if you provide no soc and no charge, SoC will run into the assert.

I hope I remembered the issues correctly from my whole tryouts. I'll come back with a PR for my BMS as soon as I have figured out the general solution for descrambling.

[fl4p]

I missed your reply.
You're right aber the soc computation and the assert. I removed the assert in the meanwhile.

This is my definition of charge, capacity and cycle_capacity:

        :param charge: The charge available in Ah, aka remaining capacity, between 0 and `capacity`
        :param capacity: The capacity of the battery in Ah
        :param cycle_capacity: Total absolute charge meter (coulomb counter). Can tell you the battery cycles (num_cycles = cycle_capacity/2/capacity). A better name would be cycle_charge. This is not well defined.
        
        

cycle_capacity increases when both charging and discharging.

[patman15]

Ok, thanks, then I got it right.

[gkathan]

hi,
I am currently trying to get my offgridtec smart pro Akku from my van integrated to my HA instance in the van ... is your work already in the latest batmon build ? would love to use it => why battery type do I have to choose if it is already in latest build ?
cheerz from vienna

[patman15]

hi, I am currently trying to get my offgridtec smart pro Akku from my van integrated to my HA instance in the van ... is your work already in the latest batmon build ?

No it is not yet integrated. I couldn't (yet) figure out how the scrambling is related to the serial number. Thus, I cannot provide a general solution that would easily work for everyone.

would love to use it => why battery type do I have to choose if it is already in latest build ?

You need to have a battery with a serial number Bxxxxx then we probably can make it work by trial and error (16 possibilities).

cheerz from vienna

Same here!

[fl4p]

@patman15 If its only 16 possibilities, we can just brute force it. You want to create a pull-request so we can integrate it into upstream? Doesn't need to be perfect and 100% tested.

[patman15]

Hmm, good point, so far I thought I could figure out the dependency from the serial number (as there is some), but actually you are right. Ok, then I need to generate the missing 15 descramble patterns. Need to find some time for that, but I will start with solving @gkathan issue than it's only 14 to go. ;-)

[gkathan]

nice :-) what do you mean with "14 to go" ? ... how long do you think will this take you ? i am eager to get my battery connected in HA :-)

[patman15]

There are 16 different scrambled communication ways. 1 I solved with my battery and one could be yours. Then there are 14 left.

[gkathan]

there is a WEEE registration number printed on the battery ... is that wahr we need?

…

On Sun, Aug 20, 2023, 11:13 Patrick ***@***.***> wrote: hi, I am currently trying to get my offgridtec smart pro Akku from my van integrated to my HA instance in the van ... is your work already in the latest batmon build ? No it is not yet integrated. I couldn't (yet) figure out how the scrambling is related to the serial number. Thus, I cannot provide a general solution that would easily work for everyone. would love to use it => why battery type do I have to choose if it is already in latest build ? You need to have a battery with a serial number Bxxxxx then we probably can make it work by trial and error (16 possibilities). cheerz from vienna Same here! — Reply to this email directly, view it on GitHub <#84 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQJLVT7ACAK3YXBYXTB2RTXWHILVANCNFSM6AAAAAAXDA76AU> . You are receiving this because you commented.Message ID: ***@***.***>

[gkathan]

ok....the smart akku app does not show the detail page in my case ... already reported this to offgridtec ... will search for a serialnumber on the battery itself tonight (it is quite hidden in my van...)

[patman15]

... and what if you press the "scanning" button in the app? Then it should list you the battery, including it's number.

[gkathan]

so....found the sticker on the battery with the serialnumber (checked with offgridtec)
it is:

20210514A16380

...but looking at that ... seems like the manufacturing date
hmmmm

[gkathan]

unfortunately the app shows only SOC, voltage and the detail drill-in is empty

[patman15]

Yep, that was the number I was looking for A16380. Unfortunately, this is an "A" type battery and not the "B" I have and I know that the "A" has different scrambling and different functionality. We would need to intercept communication and figure out how that works. That is a longer project ...

[gkathan]

ok ... once I have fixed the BMS of the battery I can fiddle around with intercepting the traffic ... but it looks like the BMS somehow died in the course of my yesterday's full charging cycle ... in contact with offgridtec already ... looks like I have to file a warranty case and return the battery ... which sucks as I need it in my van ...

…

On Tue, Aug 22, 2023, 17:26 Patrick ***@***.***> wrote: Yep, that was the number I was looking for A16380. Unfortunately, this is an "A" type battery and not the "B" I have and I know that the "A" has different scrambling and different functionality. We would need to intercept communication and figure out how that works. That is a longer project ... — Reply to this email directly, view it on GitHub <#84 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQJLVXMXIMJD2AB5PX4AJ3XWTFSXANCNFSM6AAAAAAXDA76AU> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[patman15]

Did you try disconnecting it (completely) for some minutes and then to charge it slightly? That helped for my battery.

[gkathan]

i was told that I can try to completly discharge it which causes the BMS to reset / reboot .... cannot do this right now because i just did such a cycle which caused the problem ;-) looks like it is somehow broken ... will buy another 200Ah battery ... and once this arrives will send back the broken one ... and when it is fixed use it as second (2x200Ah)
will tell you once new battery is here for testing (curious whether it is an "A" or "B" model

[gkathan]

hi,
got a new 200Ah battery of same type....what shall I do to sniff the Bluetooth protocol?

[gkathan]

...is worth buying such a sniffer ? https://www.antratek.de/bluefruit-le-sniffer-bluetooth-low-energy-ble-4-0-nrf51822?gclid=Cj0KCQjwi7GnBhDXARIsAFLvH4nSqcKhBjXnV8WopCg6yoKl1N6S-W6oOKMZPXgueVaRzfUWKbCDbAAaAp7UEALw_wcB

[gkathan]

or is it "classic" Bluetooth (not low energy) ... Ubertooth One 2.4GHz Wireless Development Bluetooth Sniffer BTLE Hacking Tool Bluetooth Protocol Analysis A https://amzn.eu/d/7nRRN4q

[fl4p]

you don't need to buy hardware. which OS do you use? on iOS , macos you can use PaketLogger.

also see https://github.com/fl4p/batmon-ha/blob/master/doc/BT%20Sniffing.md

[gkathan]

have android, Linux and windows ... no iOS

…

On Mon, Aug 28, 2023, 14:03 Fabian ***@***.***> wrote: you don't need to buy hardware. which OS do you use? on iOS , macos you can use PaketLogger. — Reply to this email directly, view it on GitHub <#84 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQJLVWZREAMALYXOWZYUJTXXSCIPANCNFSM6AAAAAAXDA76AU> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[fl4p]

for android see this https://stackoverflow.com/questions/23877761/sniffing-logging-your-own-android-bluetooth-traffic

if you have a app on linux or windows that connects to the bms you can use Wireshark

[gkathan]

ok ... and for what shall i look for once the sniffer is active ?

…

On Mon, Aug 28, 2023, 15:07 Fabian ***@***.***> wrote: for android see this https://stackoverflow.com/questions/23877761/sniffing-logging-your-own-android-bluetooth-traffic if you have a app on linux or windows that connects to the bms you can use Wireshark — Reply to this email directly, view it on GitHub <#84 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQJLVXJ2L7L4WUMQALLHO3XXSJYNANCNFSM6AAAAAAXDA76AU> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[patman15]

@gkathan I can tell you how I did it, but again, please note, I have a "B" type of battery which probably has a different BMS.
I used BT debugging on my phone to record the communication between the battery and the app.
Then I wrote a sketch for an ESP32 to emulate a "fake" battery that would reply to BLE request to check which values are shown in the app correspond to the requests. Did a lot of value debugging and trial and error. Finally I wrote an ESP32 sketch to query the battery and show the numbers. Last I transformed the latter into a class for batmon.
I didn't know how to decompile the apk, but that is probably an easier approach. Let me know if you need something for my approach or if you need my sample code (ESP32 or the class for batmon). I can somewhere upload it but as mentioned, currently it's of limited use for users of batmon ...

[gkathan]

...successfully decompiled the offgridtec smart Akku Viewer APK and now studying the source code to find the relevant snippets ... will let you know

[gkathan]

@gkathan I can tell you how I did it, but again, please note, I have a "B" type of battery which probably has a different BMS.
I used BT debugging on my phone to record the communication between the battery and the app.
Then I wrote a sketch for an ESP32 to emulate a "fake" battery that would reply to BLE request to check which values are shown in the app correspond to the requests. Did a lot of value debugging and trial and error. Finally I wrote an ESP32 sketch to query the battery and show the numbers. Last I transformed the latter into a class for batmon.
I didn't know how to decompile the apk, but that is probably an easier approach. Let me know if you need something for my approach or if you need my sample code (ESP32 or the class for batmon). I can somewhere upload it but as mentioned, currently it's of limited use for users of batmon ...

is it possible to get access to your code ... would like to learn how to access the offgridtec battery ...
can you drop me your python code off your working offgridtec type"B" Plugin ?

[gkathan]

hi,
can you let me look at your code / implementation of the "B" type offgridtec akku ... so that I can derive / learn how to access the "A" battery ?
cheerz and thanx

[patman15]

Sure! I'll fork and upload the changes their. Give me a few days to cleanup and prepare.

[gkathan]

would like to understand better how to write a class for batmon ... is reading the documentation of batmon sufficient to get an understanding how to code it ?

…

On Tue, Aug 29, 2023, 19:11 Patrick ***@***.***> wrote: @gkathan <https://github.com/gkathan> I can tell you how I did it, but again, please note, I have a "B" type of battery which probably has a different BMS. I used BT debugging on my phone to record the communication between the battery and the app. Then I wrote a sketch for an ESP32 to emulate a "fake" battery that would reply to BLE request to check which values are shown in the app correspond to the requests. Did a lot of value debugging and trial and error. Finally I wrote an ESP32 sketch to query the battery and show the numbers. Last I transformed the latter into a class for batmon. I didn't know how to decompile the apk, but that is probably an easier approach. Let me know if you need something for my approach or if you need my sample code (ESP32 or the class for batmon). I can somewhere upload it but as mentioned, currently it's of limited use for users of batmon ... — Reply to this email directly, view it on GitHub <#84 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQJLVSUMHP4IE5ZUA37C5LXXYPCTANCNFSM6AAAAAAXDA76AU> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[patman15]

Probably @fl4p has better experience than me, I simply threw the git repository into the addon folder and installed it as local addon. That way I can simply edit the files and then rebuild to test. I'm pretty sure there are more sophisticated methods than that. 8-)

[fl4p]

You can just run the add-on stand-alone, that's how I usually do it. Install the requirements, and create options.json where you put the BMS address. see doc/Standalone.md.
it'll work without mqtt set up, just see the command line logs

[patman15]

@gkathan just had a look into /sources/com/yscoco/smartbattery/utils/EncryptUtils.java which seems to be the code for this scambling stuff. Looks like the A type batteries just differ in the way the EncyKey is derived from the serial number. Which would mean, with the right key you should be able to access your battery with the rest of my code if you can figure out which registers are available from /sources/com/yscoco/smartbattery/activity/DeviceInfoActivitiy.java

[gkathan]

ok ... now found some time to read your code ... some questions:

• the _CRYPT = b'\x29\x28\x2B\x2A\x2D\x2C\x2F\x2E\x21\x20\x58\x5B\x5A\x5D\x5C\x5F' is coming from where ? is this the same "key" when you refer to the type A battery encryption key which is derived from my serial number ?
• I cannot find the conv.py file in your oft branch ... am I blind ;-)
• so you mean with just tweaking / understanding the encryption from the decompiled java classes ... all I need to do is to define the "correct" _CRYPT byte array ?
  thanx

[patman15]

* the   _CRYPT = b'\x29\x28\x2B\x2A\x2D\x2C\x2F\x2E\x21\x20\x58\x5B\x5A\x5D\x5C\x5F' is coming from where ? is this the same "key" when you refer to the type A battery encryption key which is derived from my serial number ?

Yes.

* I cannot find the conv.py file in your oft branch ... am I blind ;-)

Did you use the links in my first post / made sure you are on the OGT branch?

* so you mean with just tweaking / understanding the encryption from the decompiled java classes ... all I need to do is to define the "correct" _CRYPT byte array ?

That would be my assumption for the ideal case.

[gkathan]

hi,
just found some time to suceesfully get my DEV environment together and tried to get your fork/branch with ogt support running ... currently i get in the logs the following:

looks like this error indicates that something fundamental is missing on my side
exec: fatal: unable to exec bashio
: No such file or directory

Batmon
s6-rc: info: service s6rc-oneshot-runner: starting
s6-rc: info: service s6rc-oneshot-runner successfully started
s6-rc: info: service fix-attrs: starting
s6-rc: info: service fix-attrs successfully started
s6-rc: info: service legacy-cont-init: starting
s6-rc: info: service legacy-cont-init successfully started
s6-rc: info: service legacy-services: starting
s6-rc: info: service legacy-services successfully started
exec: fatal: unable to exec bashio
: No such file or directory
s6-rc: info: service legacy-services: stopping
s6-rc: info: service legacy-services successfully stopped
s6-rc: info: service legacy-cont-init: stopping
s6-rc: info: service legacy-cont-init successfully stopped
s6-rc: info: service fix-attrs: stopping
s6-rc: info: service fix-attrs successfully stopped
s6-rc: info: service s6rc-oneshot-runner: stopping
s6-rc: info: service s6rc-oneshot-runner successfully stopped

[gkathan]

ok ... somehow i came a step further ... have now your branch/fork running on my raspi in the van where my "a" type battery is running ... current log shows that encryption has to be adapted ... now i can try to hack this :-)

[7wells]

@patman15

Further, I wrote a native BT integration for HA that automatically detects my battery and adds it.

Would you mind sharing details about this? Thank you so much! 👍

[patman15]

@7wells There is a screenshot above what else would you like to know?

[fl4p]

@patman15 yes, porting batmon to the HA integration API is my intention, haven't started it yet.
let's try to join our efforts here.
I haven't dig much into the integration API.
It would probably make most sense to have a separate repository that can be added to HACS.
And having everything under bmslib/ in a git submodule or a pip module, that can be used by both the integration and the add-on.
What are your thoughts?

[patman15]

@fl4p thanks for answering!

let's try to join our efforts here.

Yep, I'd love to!

I haven't dig much into the integration API.

Well, I'm done, it's working for my BLE battery. My current state is, battery is automatically added as soon as it appears on the BT adapter. As sensors I currently only add those types that are available native in HA. (Could be changed, but I wanted to follow KISS principle ;-)) I'd really like to keep it minimal and do the rest extra. So it depends on how you want to handle, e.g. energy meters (which I would see outside, as there are solutions for that)

It would probably make most sense to have a separate repository that can be added to HACS.

Agree, I'm just preparing one (will take a few days more) with an initial starting point that works with the OGT battery of mine to make gkathan happy. :-)

And having everything under bmslib/ in a git submodule or a pip module, that can be used by both the integration and the add-on.

Yes, I do agree to that. Submodule can be done as long as it is HACS, if you think even on going to HA directly, then a pip module would be required. I'm good with both, just noticed that there are still only very few basic BLE integrations in core. Wonder why?
My current integration expects a very simple API. It calls the submodule constructor with an BLEdevice. Then only one method is required async def update(self) -> dict. The return value is expected to have the format {"sensor_key": value}. A sample would be: {'temperature': 21.0, 'voltage': 13.229, 'current': 0.0, 'battery_level': 56, 'cycle_capacity': 219.73369, 'runtime': 3932100}
So the only thing left is refactor the classes under bmslib/ to that interface and allow the integration to detect and instantiate different type (which is simple).

@fl4p should we start a new discussion on that? My plan is to publish the HACS integration on my github account so everyone can have a look. I'm especially interested which functionality of your current solution you expect to be there later. E.g. MQTT, or stand-alone working etc. Probably, aligning on the (interface of the) submodules in bms-lib/ and re-using them for the two work-flows is even better?
Let me know your thoughts how to take it from there and how I can support you. Excited to join forces!

[fl4p]

@patman15
Yes, let's start a new discussion, its getting a bit messy here otherwise.

I have little time at the moment for batmon.
I think best is to use an intermediate interface, like batmon already does with e.g. BmsSample. We can then publish data of this data structure to HA via MQTT (add-on) or the integration API. This way we have a modular approach and we split the sources (BMS) from the data sinks (MQTT, HA integration API)

I will get back as soon as I have more time

[patman15]

possible that I can get access to try ?

Sure, let me refactor a bit and then I will try to publish my first HACS integration. Just wanted to give you some heads-up that things are progressing (even with long voids in between)

[patman15]

Unfortunately noticed that the "A" type batteries not only have a different encryption but also a different frame format. Need to have a look again. "B" type does work now.

[7wells]

@7wells There is a screenshot above what else would you like to know?
Ah, sorry, I might have misunderstood your "wrote a native BT integration for HA that automatically detects my battery and adds it". At least from your screenshot I do not understand what you meant by "native BT integration...".

[patman15]

@7wells In contrast to the batmon addon, I did an integration that uses HA bluetooth stack and does not require MQTT (addon). Does this answer your question?

[7wells]

Sorry that I might have overlooked the obvious, but do you offer your integration code somewhere?

[patman15]

Give me some days to prepare a repository for a HACS integration and then I will publish. Just finished testing today, batteries of type A and B are working now.

[patman15]

@7wells, @gkathan I now published my current beta version here: https://github.com/patman15/BLE_BMS-HA feedback welcome.

[patman15]

Just merged the latest and greatest changes. Please verify that you have version tag 5a29ef2.
Wish you a relaxing weekend, weather is supposed to be nice. 😄

[gkathan]

hej .... you are just PLAIN AWESOME 🤘🤘🤘 .. just reinstalled my HA raspi in the van and did looots of upgrades first, installed your HACS integration ... AND ... it just WORKED out of the box without a single glitch ... detected by offgridtec battery and all values are online now
fantastic work
and best greetings from Austria
c

[patman15]

@gkathan thanks for the nice feedback and I'm happy it works! Was quite some effort for 2 users and a product that is not sold anymore. 😁
Greeting from Austria as well!

[gkathan]

you also from Austria ? where ? I live in Vienna and currently in Steyr

• we should meet - the only 2 customers 😂😂

[fl4p]

So cool to see your integration working @patman15 !

[gkathan]

ok one question ... it looks like since I connected HA with your integration to the smartbat ... the offgridtec app no longer sees the battery to connect to it ... looks like only one connection to the bms is allowed ... true? cheerz gerold kathan :: +43 699 1973536

…

On Sat, Mar 30, 2024, 14:43 Fabian ***@***.***> wrote: @patman15 <https://github.com/patman15> Yes, let's start a new discussion, its getting a bit messy here otherwise. I have little time at the moment for batmon. I think best is to use an intermediate interface, like batmon already does with e.g. BmsSample. We can then publish data of this data structure to HA via MQTT (add-on) or the integration API. This way we have a modular approach and we split the sources (BMS) from the data sinks (MQTT, HA integration API) I will get back as soon as I have more time — Reply to this email directly, view it on GitHub <#84 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQJLVUO2A2XM63JUVW4JETY22XONAVCNFSM6AAAAAAXDA76AWVHI2DSMVQWIX3LMV43SRDJONRXK43TNFXW4Q3PNVWWK3TUHM4DSNJZGQ3DK> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[patman15]

Hey! Correct, the BMS allows only one connection at a time. In order to keep it logic, I decided to permanently keep the connection open within the integration. There is the possibility to change that (integration tries to connect, reads data, disconnects every 30s) but this would mean that it is "random" when the app gets data and when the integration. You can disable the device then it should disconnect after some time and the app work again.
patcalc@buerotiger.de if you want to contact me per PM.

[patman15]

@gkathan thanks again for testing the integration! If there are further issues please raise one for my integration or contact me directly to not mess up things here.
I will wait for Fabian to come back to me to continue discussions on joining efforts in #213 and close this topic now.

[gkathan]

one last thing:

• the only thing missing compared to the app is to have an indication when the battery is charging (boolean and/or the amount of amp which is going into the battery)
• or am I just missing it?
  cheeerz

[patman15]

Hi! Current sensor should be available, showing negative values for supply and positive values for charging. If you are looking for a separate binary sensor stating charging/non-charging I would need to implement it. Nevertheless, this would be a "sign indicator" of the current, as the BMS does not deliver charging indication natively.
It's even in your picture here #84 (reply in thread), 2nd from top current

[gkathan]

hi just created an issue in the repo * the Current and Power entities/sensors are both always zero in my case regardless whether it is charging or discharging patman15/BMS_BLE-HA#2 if you need Support for the type-A battery please let me know how I can assist cheeerz and thänx so much gerold kathan :: +43 699 1973536

…

On Mon, Apr 1, 2024, 11:06 Patrick ***@***.***> wrote: Hi! Current sensor should be available, showing negative values for supply and positive values for charging. If you are looking for a separate binary sensor stating charging/non-charging I would need to implement it. Nevertheless, this would be a "sign indicator" of the current, as the BMS does not deliver charging indication natively. — Reply to this email directly, view it on GitHub <#84 (reply in thread)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABQJLVREHCVLEANTPP6XIELY3EPRHAVCNFSM6AAAAAAXDA76AWVHI2DSMVQWIX3LMV43SRDJONRXK43TNFXW4Q3PNVWWK3TUHM4DSNZQHA2TI> . You are receiving this because you were mentioned.Message ID: ***@***.***>