# BMS Communication goes offline after a few hours: VE.CAN TEC 128 Error-Passive

**URL:** <https://community.victronenergy.com/t/bms-communication-goes-offline-after-a-few-hours-ve-can-tec-128-error-passive/60769>\
**Category:** Node-RED\
**Tags:** node-red, ekrano\_gx, pylontech, expert, cerbo\_gx, cerbo-gx\
**Created:** [23 July 2026 09:33 UTC](https://community.victronenergy.com/t/bms-communication-goes-offline-after-a-few-hours-ve-can-tec-128-error-passive/60769 "2026-07-23T09:33:28Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![walterw](https://avatars.discourse-cdn.com/v4/letter/w/e95f7d/32.png) [@walterw](https://community.victronenergy.com/u/walterw)\
**Post date:** [23 July 2026 09:33 UTC](https://community.victronenergy.com/t/bms-communication-goes-offline-after-a-few-hours-ve-can-tec-128-error-passive/60769/1 "2026-07-23T09:33:28Z")

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Hi,

we installed a new system, where we use a Victron Ekrano as a master BMS to collect information from several batteries (400 kWh) via serial.  
In node red, this information is then packed into pylontec CAN msgs and sent via socketcan VE.CAN port 1 to a Victron cerbo GX MK2 (where all the Multiplus are connected to.) The cerbo (Firmware V.3.80~39) is receiving it on VE.CAN port 2, (BMS LV 500 kbit/s). Connection is done with a CAT7 cable, Terminators on both ends. Works fine…

except after a few hours, the Cerbo CE.Can port 2 goes into Error-passive, TEC:128, and a handful of new dropped packages on TX. This results in “BMS Lost” Error.  
After disabling the can port and enabling again, system runs again for 2-10 hours without any issue.  
I can also get it working by disabling and enabling the CAN port on the Ekrano side.

Any idea why this is happening?