Victron energy Orion-Tr DC-DC Manuel page 14

5. Smart alternator compatibility
The engine is running detection is based on the voltage of the
starter battery. The charger is not always able to measure the
exact starter battery voltage because of voltage drop over the
input cable. The voltage drop is determined by variables like
current, cable length and cable gauge. The "engine on detection
sequence" (see figure 7) will perform periodic tests to determine
the exact starter battery voltage during charging. The test result
determines if the engine is running and charging can be enabled.
This feature is only active in charger mode and when "engine
detection override" is not activated. In converter mode the "input
voltage lock-out" determines when the output is active.
Configurable with VictronConnect
Figure 7: Engine on detection sequence
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