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hardwic asked

Cerbo with 10 MPPTs losing connection

We have 2 sites with 3 phase 15000 Quattros, Cerbo, FreedomWon BMS battery and 10 smart mppts.

Both for some reason keeping having the MPPTs switch to float and back to remote control. The power then fluctuates wildly.

Both sites have the BMS on the same bus and I see many TX/RX can errors.

We originally tried to have the BMS on the BMS-CAN interface but it would not come up even though the same cable/bms worked on a Octo.

The 1 site BMS does not auto sense the baud rate but the other does, so we will arrange to move the cable to see if it resolves the problem. If that works we will reprogram the other BMS to 500kbs and try again.

Can you confirm this is definitely the issue as both sites are not that accessible.

MPPT SmartSolar
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hardwic avatar image hardwic commented ·

We can confirm moving the 1 BMS onto a separate CAN bus does not solve the problem. Bellow the MPPT state and resulting yield.

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hardwic answered ·

I must just add that most the issues here seem to relate to CAN cable being run in conduit with DC power conductors. Varying DC loads could result in magnetic interference in adjacent comms cables. We have now corrected this and are monitoring.

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michelg avatar image michelg commented ·

Hi Hardwic ! I had such kind of issues with the ET112 and RS485 wiring, even using the Victron cable. By moving it only a few centimeters did solve my issue.

You are probably the right way. Interferences are a nightmare to detect and fix. Good luck.

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ michelg commented ·

Thank you both for the comments. I too have had my fair share of mind boggling troubleshooting issues with these comms due to interference. It is VERY tricky to diagnose, as it can seem to resolve itself, and then reoccur for no good reason.

With all equipment independently testing well and without fault on the bench.

I will update the manuals for both to at least made some reference that there needs to be separation between current carrying conductors and data comms cables. The temptation for an installer (without a warning) is to put them close together for neatness.

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