Two brand new Quattro 48/5000/70 instantly trigger battery BMS Short Circuit when connecting DC

Q&A and troubleshooting
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1

Hello everyone,

I have a very unusual issue with two brand new Victron Quattro 48/5000/70 units.

System:

  • 48V LiFePO4 battery (FIDUS Plus 16kWh)
  • Both Quattro units are brand new and have never been powered on.
  • Battery works normally with a Victron MultiPlus.
  • Cerbo GX, Lynx Distributor and battery are operating correctly.

Problem:
The moment the positive DC cable touches either Quattro (even with the front switch OFF), the battery BMS immediately reports “Short Circuit” and disconnects.

Tests already performed:

  • Same result with both Quattro units.
  • Direct connection to the battery (Lynx completely bypassed).
  • AC IN and AC OUT completely disconnected.
  • Correct polarity verified.
  • Same battery powers a MultiPlus without any issue.
  • The Quattros never get a chance to boot because the BMS trips instantly.

Has anyone experienced this with the Quattro 48/5000/70?

Could this be related to capacitor inrush current or a failed pre-charge circuit?

Tomorrow I will measure the resistance between DC+ and DC− on both Quattros before attempting a manual pre-charge.

Any suggestions would be greatly appreciated.

2

On the right track. You need a better way to pre charge. If you look around the forums, this is a common issue with the first power on.

I have found a decent 5W resistor does the job.

Other have come up with ideas.

3

Theres also a victron precharge cable if you only need to do this a couple times

If you want to permanently install a precharge resistor, a 20 to 30 ohm power resistor and a pushbutton will do fine.