the USB GPS needs to be unplugged (again) for both BMV’s to get recognized after reboot. (ve-direct, as battery monitor on the inside connector, as DC system on the external connector on mp-ii 5kVA GX
USB GPS could indeed be EMI as you said in one of the other topics. Did that also happen in prior versions? Ie. can you reproduce that in v3.63?
Yes and no.
I had issues before when I a second BMV was connected by USB with a duppa.net isolated usb-to-rs232 adapter (both single and quad). That turned out only to be manageable by using the shortest USB cable possible.
I ended up moving the 2nd BMV to internal VE-Direct to free the USB port for the GPS and noticed it had issues with longer USB cables just as well. And issues with both the ve-direct connected BMV’s during reboots when the USB GPS is connected. So all that points to EMI, not much that can be done about it I’m afraid.
So it seems to be USB hardware possibly driver and signal timing related, not GPS nor rs232 nor ve-direct.
Also medium level difficult to reproduce: the use of a 2 meter (good and shielded) USB extension cable pretty much guarantees USB issues during reboots and/or high inverter power.
Not unimportant: all this on MP-II 5000 GX where the cerbo unit is mounted inside the MultiPlus
Ah understood.
I’ll close this one then.
I don’t know a solution either - sorry.
I guess it’s more an issue to create awareness of this issue for other people to understand the limitations of the current hardware and advise the to try keep USB cable short and/or possibly try use a good (powered) hub of sorts.
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I ordered a powered USB hub for further testing:
- It is now possible to use a shielded 2 meter USB extension cable between the hub and the USB GPS. Before the GPS would either not be recognized or disconnect within a short period if time.
- Unfortunately this does not solve the 2nd VE-Direct connected BMV not being recognized after (beta) firmware update with a/the USB device (hub, gps or otherwise) connected
- A plain reboot, not unplugging USB, did resolve getting the 2nd BMV recognized. Not unimportant in remote update context.
Update after more trail and error testing (unavoidable with intermittent issues):
- The 2nd VE-Direct connection inside the housing of the MP-II 5000 GX seems to be affected more (or even only) by the ‘not recognized after firmware upgrade / reboot’ issue.
- Moving the 2nd BMV connection from the 2nd VE-Direct, back to a USB to VE-Direct (duppa, quad isolated USB to rs232) connection, but behind the powered USB hub this time, resolves all reconnection issues (for now).
Preliminary advisory for MP-II xxxx GX devices:
- Do not rely on the internal VE-Direct connection
- Do not use long cabled USB devices directly connected to the GX device
- Do use a good powered USB Hub with a short USB cable to the MP - GX
- Do use good isolated USB to VE-Direct cables from Victron or build one based on the duppa rs232 debug boards (single/quad) that have been reported to provide good results by multiple persons, me included.
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