Victron energy Lynx Smart BMS 500 Manual page 18

This setting is automatically configured upon initial power-up and after a "Reset to defaults". It is enabled by default.
• enabled: recommended setting. A visual or audible device linked to the programmable relay is activated in case of a pre-alarm.
• disabled: If disabled, it will ignore the discharge current limit at pre-alarm setting.
Older Victron Lithium Batteries Smart manufactured before 2019/2020 do not have the pre-alarm signal.
Nevertheless, the Lynx Smart BMS also generates the pre-alarm signal for these batteries with the restriction
that the threshold for this is derived from the undervoltage alarm setting (in the battery) of 2.6V - 2.8V. The
undervoltage alarm then occurs with a fixed delay of 30 seconds after pre-alarm.
Set the Relay setting:
The programmable relay has two operation modes: Alarm relay and Alternator ATC.
• When set to Alarm relay mode, the Alarm relay setting becomes active and continuous or intermittent operation can be
selected. In intermittent operation the relay switches on and off every 0.8 seconds.
• When configured for Alternator ATC mode, the relay will only activate when the contactor is closed. Before the contactor
is opened, Alternator ATC is opened first and 2 seconds later the contactor. These 2 seconds ensure that the alternator is
switched off before the battery is disconnected from the system.
DVCC settings:
DVCC is forced on and cannot be turned off. However, a few settings can be changed, which are described below.
Please note that these settings only affect compatible DVCC devices such as Victron inverter/chargers and Solar MPPT chargers.
• Discharge Current Limit at pre-alarm (default "No"): if set to "Yes", the discharge current limit is already set to 0A in the event
of a pre-alarm, while the ATC contact remains closed. In this way it's possible to save some battery power for essential DC
loads, for example on boats such as lighting, bilge pump and navigation.
• Absorption time: is set to 2 hours by default. This can be adjusted if necessary.
• Repeated absorption interval: in days at which a new full charging cycle is started, if the battery SoC does not fall below the
SoC threshold. The default is every 30 days and can be adjusted if required.
• SoC threshold: is set by default to 70%. This is the threshold at which the Lynx Smart BMS starts a new full charging cycle.
This can be adjusted if required.
A new charge cycle means that the CVL (charge voltage limit) is increased from 13.5V (for a 12V battery) to 14.2V.
In addition to the SoC threshold, a new charging cycle is started after a firmware update, when the battery voltages are below
12V/24V/48V (3V per cell) or when a low cell voltage is detected.
Battery monitor settings:
Unlike other battery monitors, the Lynx Smart BMS battery monitor settings are mostly fixed settings and are not customisable.
The reason for this is that the Lynx Smart BMS is always used together with Victron Lithium Batteries Smart and a lot of battery
monitor parameters are therefore known because they relate to the battery type.
The following settings are adjustable. A full list of all settings used can be found in the
• Charged voltage: the voltage at above which the battery monitor synchronises and resets the SoC to 100%. For
synchronisation to happen, the tail current and charged detection time conditions need to have been met as well. The default
is set to 14.0V and can be adjusted if necessary. In case the system voltage setting is changed, the charged voltage setting
needs to be adjusted as well.
• Tail current: the current at below which the battery monitor synchronises and resets the SoC to 100%. For synchronisation to
happen, the charged voltage and charge detection time conditions need to have been met as well. The default is set to 4% and
can be adjusted if needed.
• Charged detection time: is the time passed after which the battery monitor synchronises and resets the SoC to 100%. For
synchronisation to happen, the charged voltage and tail current conditions need to have been met as well. The default is set to
3 minutes and can be adjusted if necessary.
• Discharge floor:* this parameter has two functions:
• Its primary use is to set the minimum SoC to determine how far you want to discharge the battery.
A limited depth of discharge is good for battery health, but also provides backup power to keep the system running, e.g. until
sunrise for solar systems.
Loads are disabled via ATD or DVCC when the set discharge level is reached, but the contactor remains closed, AUX
remains ON and the ATC contact remains closed as well to allow recharging the battery. At the same time, a Low SoC alarm
is issued.
Setting the discharge floor to zero (not recommended), disables this feature.
Page 15
Lynx Smart BMS
Appendix section 10.3. [34]
Configuration and settings