jk-bms_grafana
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PurpleAlien
Multiple bms's
Qq: I have 3 bmsses connected to the same rs485. Any thoughts on how to address them individually? Love the script!
It's not possible - you have to use separate connections. One of the reasons is that RS-485 is only a hardware interface definition and does not dictate a protocol. The BMS actually only has a TTL (think UART) output that gets converter with a dongle to RS-485, but does not add any protocol as such - it just converts whatever is sent on the TTL side to RS-485 signalling and vice versa. There is no addressing on the BMS TTL side, so no differentiation on the RS-485 side either.
Personally I run four of these BMS. I did away with the dongles and connect to TTL directly with a TTL to USB converter, and hooked them up to a USB hub each with their own ttyUSBx /dev entry.
Hi Johan,
Many thanks for the fast reply. Would you mind sharing your setup (which components, the script you used)? There is a ton of stuff out there but sometimes difficult to see the forest from the trees …
Cheers from NL,
H
From: Johan Dams @.> Sent: Wednesday, September 13, 2023 7:23 AM To: PurpleAlien/jk-bms_grafana @.> Cc: heggink @.>; Author @.> Subject: Re: [PurpleAlien/jk-bms_grafana] Multiple bms's (Issue #4)
It's not possible - you have to use separate connections. One of the reasons is that RS-485 is only a hardware interface definition and does not dictate a protocol. The BMS actually only has a TTL (think UART) output that gets converter with a dongle to RS-485, but does not add any protocol as such - it just converts whatever is sent on the TTL side to RS-485 signalling and vice versa. There is no addressing on the BMS TTL side, so no differentiation on the RS-485 side either.
Personally I run four of these BMS. I did away with the dongles and connect to TTL directly with a TTL to USB converter, and hooked them up to a USB hub each with their own ttyUSBx /dev entry.
— Reply to this email directly, view it on GitHubhttps://github.com/PurpleAlien/jk-bms_grafana/issues/4#issuecomment-1716966132, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AA6NSF2IYAGVC3AY5WEA7F3X2E7LFANCNFSM6AAAAAA4VQFIWY. You are receiving this because you authored the thread.Message ID: @.@.>>
I've attached the script I use to this message (with .txt extension added).
data_bms.py.txt 10.local.rules.txt
It's an expanded version of the one on in git. I never really thought it would be useful for anyone else, but maybe I should add it in any case.
I also added some udev rules which allows to distinguish between the 4 BMS by name even though they all use the same type of TTL to USB converter. The pin-out on the JK is in the Readme on the git repo.
Which ttl to USB do you use if I may ask?
From: Johan Dams @.> Sent: Wednesday, September 13, 2023 10:02 AM To: PurpleAlien/jk-bms_grafana @.> Cc: heggink @.>; Author @.> Subject: Re: [PurpleAlien/jk-bms_grafana] Multiple bms's (Issue #4)
I've attached the script I use to this message (with .txt extension added).
data_bms.py.txthttps://github.com/PurpleAlien/jk-bms_grafana/files/12594977/data_bms.py.txt 10.local.rules.txthttps://github.com/PurpleAlien/jk-bms_grafana/files/12594978/10.local.rules.txt
It's an expanded version of the one on in git. I never really thought it would be useful, but maybe I should add it in any case.
I also added some udev rules which allows to distinguish between the 4 BMS by name even though they all use the same type of TTL to USB converter. The pin-out on the JK is in the Readme on the git repo.
— Reply to this email directly, view it on GitHubhttps://github.com/PurpleAlien/jk-bms_grafana/issues/4#issuecomment-1717138192, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AA6NSF4TVNJ6RR642ULRHL3X2FR6TANCNFSM6AAAAAA4VQFIWY. You are receiving this because you authored the thread.Message ID: @.@.>>
Excellent. Thx! I currently use 3 RS485 interfaces (one for each bms). Similar.
From: Johan Dams @.> Sent: Thursday, September 14, 2023 11:13 AM To: PurpleAlien/jk-bms_grafana @.> Cc: heggink @.>; Author @.> Subject: Re: [PurpleAlien/jk-bms_grafana] Multiple bms's (Issue #4)
Something like this:
https://www.amazon.de/gp/product/B07TFSZ3ZP
— Reply to this email directly, view it on GitHubhttps://github.com/PurpleAlien/jk-bms_grafana/issues/4#issuecomment-1719066202, or unsubscribehttps://github.com/notifications/unsubscribe-auth/AA6NSF5G6MMW7LWFM4XC7O3X2LDBRANCNFSM6AAAAAA4VQFIWY. You are receiving this because you authored the thread.Message ID: @.@.>>