Quattro reading lower voltage on DC Bus

DIY
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1

My Quattro inverter 48/5000/70-2x100 120V is now consistently reading ~0.3V less in the DC Bus than actual. This is a new behaviour that was not present before.

I have measured voltage accross the terminals of the Quattro with a digital multimeter and compared against values reported by the Quattro on Cerbo and the Quattro is lower by 0.3V. Kind of problematic because it is pushing the battery cells a bit higher than I have it setup when terminating charge. Other devices in the network, such as MPPT report the correct voltage, only the quattro is reading lower than actual accross its terminals.

DVCC is not enabled in my system. The Quattro uses its onboard DC voltage monitor (which is reading lower) for charging.

MK2 Device MK3 / MK2 11700216 / FWv492

Is there some calibration of the Quattro DC Bus voltage possible? Or is this a hardware failure?

2

If the quattro terminals are slower than they should be under charge would happen, not over charge.

If this was not happening and now it it check terminal torque and any resistance points.

For the MP2 some users have reported that disabled voltage sense can help, otherwise no calibration by the end user is possible

3

Thank you. Yes, it pushes the cells higher (overcharge) because it reads (incorrectly) the battery is at a lower voltage, so it keeps increasing the voltage until it achieves the setpoint, but now the batteries are at a higher level than setpoint. Changing the setpoint by reducing it by ~0.3V could help, but I still wouild have the same issue on the low end with an earlier cutoff.

Terminals were checked to make sure they are secured and clean/no corrosion.

Disabling Voltage Sense is not an option on VE Config for Quattro FWv492. Apparently this was added later. Why would disabling voltage sense help? Victron list this as a “Diagnostic only” feature. Would it use a different circuit to measure voltage?