DESS not stopping PV production when energy prices are negative

[wedo (Darryl)]

Hi all,

Last weekend the dynamic energy prices where extremely negative in the Netherlands. The highest negative price was -40 cents/kWh. I’ve multiple systems running with Multiplusses and Multi RS, all in three phase configuration, with PV’s connected to the Multi RS and AC-coupled systems like Enphase with dynamic limiter activated.

Unfortunately I saw on all systems that the PV’s kept producing when energy prices for buying energy are negative. It is obvouisly economically better to turn of the PV and use as much energy from the grid as you get paid for it.

I’ve seen multiple topics about this subject on this forum, but I haven’t seen an answer from the Victron Experts/Developers. Are there plans to fix this? Now I see temporarely fixed to create a flow in Node-Red to switch off PV when buying prices are negative.

Hope to hear from the Victron Experts/Developers

[ron_h]

In node red I activate relay 2 of mine cerbo GX when buy price is negative.
This than turns off mine Enphase system.

[Ton_Gans]

Hi Ron,
How do you do that? I’ve also got Enphase but I turned the breaker off

[ron_h]

If you have an envoy S metered you can set under " Stroomproductie beperkt door envoy" the following:

Envoy has 4 digital inputs, use input 1 to turn on or off the power.

Other way would be to activate sunspec on your envoy, this way you could activate zero export in venus os.

[Ton_Gans]

Thanks.
Can I ask you to share your Node Red flow here?

[wedo (Darryl)]

Using sunspec to control Enphase is what I have now, but it is indeed zero export. I want Victron to switch off the PV production, not reducing it, during negative energy prices

[ron_h]

On Massage:

let price = msg.payload.records.deGs[0][1]

msg.payload = (price <= 0.0) ? 1 : 0
let fill = 'red'
let text = 'Nope, positive price'
if (msg.payload) {
     fill = 'green'
        text = 'Yes! Negative price'

}
text += ‘: €’ + price.toFixed(2)
node.status({fill, shape: ‘dot’, text})
return msg;