Figured I would share in hopes of saving the next guy some time. My setup is completely off grid with generator backup for these lousy short, sunless Winter days. Been looking for a way to control my generator through my CerboGX, but as you know, Victron does not support momentary signal for start/stop generator control (which mine requires). By default, CerboGX will open/close a relay based on set parameters to run the generator. If any of you, like me, have a 2-wire or 3-wire momentary switched start/stop generator (I have a Westinghouse 9500DF), the solution is to use two separate timed relays that take the Cerbo’s latched open/closed circuit and convert it to a momentary pulse. Pictures below. Hope this is useful to some of you off-gridders out there!
I am interested to learn more. I have seen a few iterations of using these time delay relays but they all appear to be using them differently. Yours is the first I have seen with 18 on both relays tied together. I am having trouble researching this topic of adding time relays to gain generator (Onan QD) control via Cerbo. The old community archive search feature appears to be dead (get same results no matter what is searched) and not finding a lot in the new community yet. Any more details would be appreciated.
guystewart
(Guy Stewart (Victron Community Manager))
3
Nice solution.
I did also see someone achieving the same effect with the 2 built in relays using node red.
Did you look into that pathway at all? The advantage being no extra hardware is required (potentially).
Hi Kevin,
My generator is a two-wire momentary start signal, and uses the same two wires for a momentary stop signal. In my setup, the first (start) relay takes the NO side of the CerboGx relay and when the Cerbo relay closes, the timed relay closes pins 15/18 for 3 seconds (timing is selectable on the relay dials). The second (stop) timed relay is connected in the same fashion to the NO side of the CerboGX relay, but the setting on the third dial of the Stop relay will close pins 15/18 for 3 seconds when the CerboGX relay returns to its ‘open’ status.
Pardon that I am not an electrician, but here’s a “schematic” of my relay wiring:
A1: +12vDC
A2: -12vDC
S: Connected to CerboGX Relay 1, NO circuit, with +12vDC on the common leg of CerboGX
15: Generator Ground
18: Generator +5vDC (taken to ground for 3 seconds to initiate start/stop)
I believe your generator is a 3-wire setup, with a separate wire for start and stop. In this case, in my wiring, I would unbond pin 18 and have two separate wires for start/stop.
My system works perfectly when it is left to do everything automatically. My only downfall which I have yet to figure out is that the Cerbo is not accurately detecting when the generator is running due to a manual start from the generator itself. If the CerboGX then decides to “start” the generator based on set parameters, it will actually shut the already running generator off (would love to have a 3-wire generator for this reason).
Thank you Tyler for the details on why your wiring is as shown and also why it would differ from my needs and my genset. Very helpful.
I happened across the following that shows how the cerbo is integrated and applies to the 3-wire setup you mentioned. I am posting here so others can find it in the new community forum as well. I am hopeful, when my relays arrive I can make the same work for me.
Got mine wired up today successfully with a small change to the pvcampbell drawing above.
Cerbo GX, Onan QD6000.
Used two GRT8-M1 relays and 50’ 3-conductor 16awg cable from genset wires to the relays. The difference to above was relay programming was “B”, not “H” or “F”. My generator requires a hold-to-start and no additional signal wiring, so H and F did not help, but B was the ticket with these relays and wiring.
With this setup has anyone figured out how to write a script that can leverage this setup and programmatically start/stop the genset? I have tried several things but ll have failed. Would love a script that works on android and other devices, so a web solution would be good. Thanks!
