Automatic Generator start/stop

2. How to wire generators with a three-wire interface

In this section:

All above Victron products and devices have a single relay; which will close when the generator needs to starts; and then expect the generator to then keep running until the relay is opened again. Or the other way around.

When having a generator that requires a start pulse and a stop pulse, such as for example Cummins/Onan generators; additional wiring is required.

To start such a genset, the open/close contact needs to be converted into a start and stop pulse. Below solution, using standard available timing relays, does exactly that: when the open/close contact closes it generates the start pulse, and when the open/close contact opens again it generates the stop pulse.

Note that this solution should only be used on gensets that have their OWN control panel monitoring and automatically stopping on loss of oil pressure and other sensors. In other words: do not wire this directly to the starter motor and fuel solenoid.


2.1. Alternative using Assistants

One solution using MultiPlus relay for start stop a three-wire generator. Use k1 and k2 relays and programmable relay assistant.

  • First to close k1 if voltage under 24v (for example)

  • Second to open k1 if AC1 is available

  • Third to close k2 if voltage over 27v (for example)

  • Last to open k2 if AC1 not available