Make Lithium Settings (If Needed) - Victron energy SmartShunt 500 A Manual

This setting sets the function of the auxiliary input, being:
Starter battery - Voltage monitoring of a second battery.
•
• Midpoint - Measuring the midpoint of a battery bank.
• Temperature - Measuring battery temperature via optional temperature sensor.

4.6 Make Lithium settings (if needed)

LiFePO4 (Lithium Iron Phosphate or LFP) is the most used Li-ion battery chemistry. The factory defaults are in
general also applicable to LFP batteries with exception of these settings:
Charge efficiency.
•
Peukert exponent.
•
Tail current.
•
Charge efficiency
The charge efficiency of lithium batteries is much higher than that of lead acid batteries. We recommend setting
the charge efficiency at 99%. For more information see paragraph 7.1.7: "Charge efficiency factor".
Peukert exponent
When subjected to high discharge rates, lithium batteries perform much better than lead-acid batteries. Set the
Peukert exponent at 1.05, unless the battery supplier advises otherwise.
Tail current
Some lithium battery chargers stop charging when the current drops below a set threshold. The tail current must
be set higher in this case.
Discharge floor
This setting is used in "the time to go" calculation and is set at 50% by default. But lithium batteries usually can
be discharge significantly deeper than 50%. The discharge floor can be set to a value between 10 and 20%,
unless the battery supplier advises otherwise.
Important warning
Lithium batteries are expensive and can be irreparably damaged due to very deep discharge or overcharge.
Damage due to deep discharge can occur if small loads slowly discharge the battery when the system is not in
use. Some examples of these loads are alarm systems, standby currents of DC loads and back current drain of
battery chargers or charge regulators.
A residual discharge current is especially dangerous if the system has been discharged all the way until a low cell
voltage shutdown has occurred. At this moment the state of charge can be as low as 1%. The lithium battery will
get damaged if any remaining current is drawn from the battery. This damage can be irreversible.
A residual current of 1mA for example can damage a 100Ah battery if the battery has been left in discharged
state during more than 40 days (1mA x 24h x 40 days = 0.96Ah).
The SmartShunt draws <1mA from a 12V battery. The positive supply must therefore be interrupted if a system
with Li-ion batteries is left unattended during a period long enough for the current draw by the SmartShunt to
completely discharge the battery.
In case of any doubt about possible residual current draw, isolate the battery by opening the battery switch, by
pulling the battery fuse(s) or by disconnecting the battery positive when the system is not in use.
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