The 717-140A-DVSR is designed for twin engine installations.
It allows the port engine to charge both the port start battery and the house battery when the port VSR is engaged. It also allows the starboard engine to charge both the starboard start battery and the house battery when the starboard VSR is engaged. This gives you a combined charge from two engines into the house battery until the voltage regulators on both engines control the charge. It also allows you to charge the house battery if steaming on one engine.
THE 717 SYSTEM INCLUDES dedicated battery switches for both the port and starboard start banks, the house bank and emergency parallel, and a 710-125A voltage sensitive relay (VSR) for each start bank. The port VSR allows the port and house batteries to be charged at the same time. When the port engine is started, and the port start battery reaches 13.7 Volts, the relay closes, combining the battery banks (port start and house) and allowing them to be charged simultaneously. When the starboard engine is started, and the starboard start battery reaches 13.7 Volts, the
relay closes, Combining the battery banks (starboard start and house) and allowing them to be charged simultaneously. When both engines are running and both start batteries have reached 13.7 Volts the house battery is charged with the combined charge of both alternators. When an engine is stopped and the start batteries voltage drops to 12.8 Volts, the connected relay will open separating the batteries. This system eliminates the possibility of draining the wrong battery and protects sensitive electrical equipment powered from the house battery from harmful engine start up spikes.
The 717 cluster is designed for twin engines without auxiliary outputs with an alternator size up to 100A.