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federico993 avatar image
federico993 asked

Help connecting REC-BMS to Raspberry Venus OS with RS485 cable

Hi, I am looking for some help to write a script that allows the Venus OS to show all the REC-BMS data parameters.

The RS-485 Communication Protocol and the RS-485 instruction set is listed in the REC manual: REC-ABMS manual (page 10)

Can anyone help?

Thanks!

@Kevin Windrem

BMSrs485
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gnagflow avatar image gnagflow commented ·

maybe this helps:

https://github.com/aaronsb/REC-BMSManager


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Kevin Windrem avatar image Kevin Windrem commented ·

Since you mentioned me specifically: Sorry, I am not able to help with this project.

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5 Answers
Joe avatar image
Joe answered ·

Hi @Federico993 !


I might have a rather stupid question, but it's one of my open questions ;) as I will be connecting all together next week.

Components:

- REC BMS 16s (Victron compatible)

- 2 x MulitPlus II 48 | 5000

- 2 x Victron MPPT 150/45 or so


Question:

How to connect the REC BMS with the Venus on the Raspberry? The Multiplus is connected via MK3-Interface to the Raspberry. The MPPTs will be connected via a VE Direct to USB cable to the Raspberry. (I assume)

As the RJ45 port of the Raspberry is busy with LAN connection already, the REC BMS-delivered DB-9 to RJ45 CAN-Cable will not work. Any experience, how to bring the devices together? I assume kind of RS-485 to USB converter (DB-9 or is there a chance to use the REC BMS delivered cable?)

Thanks for a short reply, think this is the last hard one for me...


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johanndo avatar image johanndo commented ·
You can use the optional rs485 USB adapter from REC or make your own RS485 USB adapter using the data pins and ground, do not connect the plus!
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Mike Dorsett avatar image
Mike Dorsett answered ·

The RS 485 on the REC unit is primarily used for programing the battery set points. For integration with the Venus OS, it is better to use the CAN bus output. If you're using a pi, then a CAN hat will be needed. The RS485 is slow compared to the CAN output.

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Kevin Windrem avatar image Kevin Windrem commented ·
USB CANbus adapters are also usable on the Raspberry PI. Avoid sloan-based interfaces however. Hats can be problematic in that you need to insure there are no conflicts between GPIO pins used for various functions: SPI bus, interrupt pins, GPIOs assigned for relay outputs or digital inputs, etc. It is certainly not plug and play.
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johanndo avatar image
johanndo answered ·

Hi, have done this 3 years ago with a python service and highly modified gui / systemcalc.py.

If you are able to program in python and qml, I can send you the source code. My system is quite complex, you need to carve out the parts you need - so it is not beginners friendly.




img-20220503-154549.jpgCell Data

This is the settings page



img-20220601-163458.jpgImage

Settings Page and some more for all parameters

img-20220601-163539.jpgmore settings...

GUI Battery overview

  1. img-20220716-143801.jpg

PM me your email address or messanger, if you want to go down that rabbit hole, you must be able to read and modify code... My system does not use DVCC / CAN integration on purpose, it runs on a Raspberry Pi4b.

Most settings are read only information, but it is easy to make them writeable.


img-20220503-154549.jpg (96.9 KiB)
img-20220601-163458.jpg (107.4 KiB)
img-20220601-163539.jpg (114.2 KiB)
img-20220716-143801.jpg (131.2 KiB)
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Mike Dorsett avatar image Mike Dorsett commented ·
your cockpit is COLD!!
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johanndo avatar image johanndo Mike Dorsett commented ·
Its the fridge for the anchor beer.
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denisdub avatar image denisdub commented ·
Just stumbled upon this @JohannDo , looking for some base python code to talk to REC-BMS through RS485 port. I can code and I am sure you figured out all the message formats, CRC calculation, etc. Any way I can get my hands on your code? Thanks in advance.
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helmutf avatar image helmutf denisdub commented ·
Can someone of you guys share code snippets or complete application, REC BMS application is "not smart" as I want to have. Thx @JohannDo
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smoothfroggy avatar image smoothfroggy commented ·

Hello Johann,

Sorry for digging up this somewhat old thread but I am working on a similar setup and would be interested by the code you have developed. Would it be possible to discuss about it and maybe share it ?

Best regards,

SmoothFroggy

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Joe avatar image
Joe answered ·

puh, thanks mates! @JohannDo I am not able to code - could try to dig in but as you said, more than beginners know-how is necessary!


So when I got it right: I might need to use a CAN --> USB inverter in order to connect to the PI. Any "working example" available w/o coding?


btw....nice work, @JohannDo

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smoothfroggy avatar image
smoothfroggy answered ·

@JohannDo

Sorry for digging up this somewhat old thread but I am working on a similar setup and would be interested by the code you have developed. Would it be possible to discuss about it and maybe share it ?

Best regards,

SmoothFroggy

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Related Resources

Additional resources still need to be added for this topic

Victron VE.Bus BMS product page

Victron 3rd party BMS compatibility page