Victron SmartShunt Battery Monitor: Settings & Calibration Guide

Key Takeaways

• Accurate State of Charge (SoC) tracking requires setting battery capacity and calibrating the Charged Voltage parameter to 0.2V–0.3V below charger float voltage.
• Automatic 100% SoC synchronisation occurs when voltage exceeds Charged Voltage and current drops below Tail Current for the duration of the Charged Detection Time (default 3 minutes).
• For lithium chemistries (LiFePO4), adjust the Peukert exponent from default 1.25 to 1.05 and the Charge Efficiency Factor from 95% to 99%.
• The Current Threshold parameter defaults to 0.10A to filter out low-level sensor noise in noisy electrical environments.
• The auxiliary connection supports starter battery voltage, midpoint monitoring in 24V and 48V battery banks, or temperature monitoring.

State of Charge Synchronisation Principles

The Victron SmartShunt measures current entering and leaving the battery bank through a calibrated shunt resistor. To maintain long-term accuracy and prevent drift, the monitor must periodically synchronise to 100% SoC.

Under Section 7.2 of the SmartShunt manual, automatic synchronisation triggers when three specific criteria are satisfied simultaneously:

1. Charged Voltage: Battery voltage remains above this threshold.
2. Tail Current: Charge current drops below the defined percentage of total battery capacity.
3. Charged Detection Time: Both voltage and current conditions persist continuously for the programmed duration (default 3 minutes, adjustable from 0 to 100 minutes).

Battery Chemistry Parameters: Lithium vs. Lead-Acid

Battery settings in VictronConnect must be matched to the installed battery chemistry:

Setting the Charge Efficiency Factor to 95% means 10Ah of charge input stores 9.5Ah of usable energy, whereas lithium cells operate with near-zero losses at 99% efficiency.

Auxiliary Input Configuration & Calibration

The SmartShunt features a secondary input terminal (AUX) configurable for three monitoring applications:

• Starter Battery Monitoring: Tracks voltage on a secondary engine starting battery.
• Midpoint Voltage Monitoring: Measures voltage midpoint on series-connected 24V or 48V battery banks under Section 9.1 to detect failing cells or inter-block imbalance.
• Temperature Monitoring: Connects an optional Victron temperature sensor for thermal compensation.

Before final commissioning, perform a Zero Current Calibration (Section 7.2.13) with all loads and chargers disconnected from the shunt load terminal.