Product Manual

If the low voltage period exceeds tshutdown charging will be disabled on engine shutdown detection.
• Voltage drop across the input cable: As seen in “engine shutdown detection sequence 1→3”, V
IN
will be lowered by Vcable.
When the alternator voltage drops fast (smart alternator) the charge-control needs some time to reduce charge current and
keep V
IN
at V
shutdown
. During this time V
cable
must not trip the voltage lock-out. Therefore, the lock-out value should be: V
lock-out
≤ V
shutdown
– V
cable.
Example: Calculate the input cable voltage drop:
• Distance between starter battery and charger: 5m.
• V
shutdown
= 13.1V. Recommended wire gauge: 16mm2.
• Cable resistance: ~1.1mΩ/m @20°C, thus R
cable
= 1.1mΩ x 10m (2x 5m) = 11mΩ.
• A 12|12-30A Smart Charger will draw about 35A from the input when running at full capacity, resulting in:
• V
cable
= 11mΩ x 35A = 385mV.
• V
lock-out
≤ V
shutdown
– V
cable
= 13.3V – 385mV ≈ 12.9V.
Cable connections, external fuses, temperature, etc. influences the total cable resistance.
Orion-Tr Smart DC-DC Charger Non-Isolated
Page 11 Engine shuthown detection