4.2. Temperature compensation
The Victron
Phoenix Smart IP43 Charger
range will automatically compensate the configured charge voltage based on ambient
temperature (except for Li-ion mode or if manually disabled).
The optimal charge voltage of a lead acid battery varies inversely with battery temperature; automatic temperature-based charge
voltage compensation avoids the need for special charge voltage settings in hot or cold environments.
During power up the charger will measure its internal temperature and use that temperature as the reference for temperature
compensation, however the initial temperature measurement is limited to 25°C as it’s unknown if the charger is still warm from
earlier operation.
Since the charger generates some heat during operation, the internal temperature measurement is only used dynamically if the
internal temperature measurement is considered reliable; when the charge current has decreased to a low/negligible level and
adequate time has elapsed for the charger’s temperature to stabilise.
For more accurate temperature compensation, battery temperature data can be sourced from a compatible battery monitor (such
as a BMV, SmartShunt, Smart Battery Sense or VE.Bus Smart Dongle) via VE.Smart Networking - refer to the 'Operation -
VE.Smart Networking’ section for more information.
The configured charge voltage is related to a nominal temperature of 25°C and linear temperature compensation occurs between
the limits of 6°C and 50°C based on the default temperature compensation coefficient of -16.2mV/°C (-32.4mV/°C for 24V
chargers / -8.1mV/°C for 6V chargers) or as configured.
The temperature compensation coefficient is specified in mV/°C and applies to the entire battery/battery bank (not per battery
cell).
Phoenix Smart IP43 Charger
Page 8
Operation
