question

thaelian avatar image
thaelian asked

Very slow refresh on Pylontech BMS info on VenusOS 2.9

@Kevin Windrem I hope you can assist, I have just upgraded to VenusOS 2.92 and installed VeCANSetup and configured the Waveshare single channel 8 MHz Pi HAT.


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The problem I am experiencing is that when a load is placed on the inverter, the BMS info on the landing page for the Pylontech BMS takes up to 3 minutes to refresh.


Here is the entry in the config.txt file:

[all]

dtparam=spi=on

#### begin CAN overlay

# Waveshare 1-channel CANbus Hat 8 MHz crystal

# instantiates as can0 ONLY !!!

# use udev rules to rename

[all]

dtparam=spi=on

dtoverlay=mcp2515-can0,oscillator=8000000,interrupt=25,spimaxfrequency=1000000

#### end CAN overlay


Is there a parameter I can set to improve the refresh rate? Or perhaps a version of VenusOS you could recommend where this doesnt happen?

Thank you


Venus OS
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5 Answers
Kevin Windrem avatar image
Kevin Windrem answered ·

Sorry, I have no idea what might be going on.

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bathnm avatar image
bathnm answered ·

It might be worth looking at the CAN Network statistics in the Venus GUOI to see if there are any stats that might help identify issues, such as bus resets. Also any logs in dmsg that might help. Could be any number of things, including CAN bus speed, hardware, kernel, drivers, etc.

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thaelian avatar image
thaelian answered ·

I am still experiencing this issue with VenusOS 3.11

Any advice?

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thaelian avatar image
thaelian answered ·

Looking at the CAN Network on VenusOS, I see 26% errors and overuns on the RX side. This makes the data refresh for the bank very very slow due to all the retries.

This worked perfectly using the same hardware on VenusOS 2.73 and only became an issue when going to version VenusOS 2.90

Rolling back to VenusOS 2.73 fixes the issue.

Any sugestions would be appreciated.

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telekatz avatar image
telekatz answered ·

Change the config.txt and increase the SPI frequency to 10MHz:

dtoverlay=mcp2515-can0,oscillator=8000000,interrupt=25,spimaxfrequency=10000000

This reduced the RX overruns on my Pi to 0.03%.

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Related Resources

Victron Venus OS Open Source intro page

Venus OS GitHub (please do not post to this)