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Neil Pavia avatar image
Neil Pavia asked

Need Multiplus to ignore generator AC during cool down

I have an SDMO Silence 6kva generator.

When CCGX send a shut down signal (opens teh relay switch) the generator continues to Run for 60 seconds to cool down - I cannot change this - its programmed this way.

during this time, for whatever reason, the cool down period triggers an overspeed alarm on the generator - but ONLY because the Inverter is still drawing load from the generator.

When I manually flick the MCB off during the cool down period, the generator shuts down without error.

Is there any way I can instruct the Inverter to ignore AC input AC1 when the switch relay is open?

Generatorshutdowngen start
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4 Answers
CM avatar image
CM answered ·

gui mods, ext transfer switch , install that and it will hold the relay until the gen is done

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Kevin Windrem avatar image
Kevin Windrem answered ·

With v3.0 (I think that's the right version) or later, cool-down can be specified in the generator setup in the stock Victron code. During this time, the Multi is told to ignore the AC input. You need to have a recent version of the Multi code however. Not sure which version added that but the latest certainly does.

BTW, GuiMods and/or ExternalTransferSwitch won't help without the latest Multi firmware.

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Neil Pavia avatar image Neil Pavia commented ·
Yeah I updated the firmware to have cool down setting but it didn’t help because at cooldown, the relay ignores AC but keeps the relay switch closed… when after the cooldown period is over, the relay switch opens (to shut down the generator) but then the genset itself does its own cooldown and at this point the AC current it generates is picked up by the Multi and I get my problem.


What I need is a way to simply ignore AC unless the generator start stop relay is closed.

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Kevin Windrem avatar image Kevin Windrem Neil Pavia commented ·

There is actually a short delay at the end of the cool-down period before the ignore AC input is lifted by the GX device. That delay is hard-coded at 15 seconds: WAIT_FOR_ENGINE_STOP = 15 in startstop.py

You could edit the file and change it to say 70 seconds but you'd need to do that after each firmware update. An adjustable post-cooldown delay was considered but no one could think of a good reason to do so. Maybe that's what should be done.

@mvader (Victron Energy) is there interest in Victron adding this?

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Neil Pavia avatar image Neil Pavia Kevin Windrem commented ·
Is this something I could edit myself?
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Kevin Windrem avatar image Kevin Windrem Neil Pavia commented ·

Yes, it is one line near the beginning of the file.

/opt/victronenergy/dbus-generator-starter/startstop.py

After you edit the file, reboot or:

svc -t /service/dbus-generator-starter

to restart the generator service.

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Kevin Windrem avatar image
Kevin Windrem answered ·

I had a few minutes and adde an adjustable post-cool-down delay. It's in GuiMods v8.17.

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mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Nice @Kevin Windrem and thanks for the report @Neil Pavia .


We’ll have another look at this for standars Venus OS as well. But that will be a while before we do.

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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ commented ·
Ps, by the looks of it, having a setting for this + proper explanation in the manual, should be sufficient indeed
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CM avatar image CM mvader (Victron Energy) ♦♦ commented ·
yes please, we would appreciate ,i certainly would
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Related Resources

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MultiPlus Generator FAQ

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Automatic Generator start/stop

 Hybrid Generators

Virtual switch - Generator start/stop

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