Is it possible to use a shelly pro3em for measurement and another shelly relay to switch on the load?
Hi @anttivaan, no, it must be a single Shelly device providing both.
I propose developing a way to control constant power loads using just a relay.
@anttivaan Noted, thanks.
Why does it even need an energy meter?
Without more details it seems you trying to do it overly complicated.
(Or am I thinking to simple? Iâm not an engineer/software developer Iâm âjustâ an installer for more then 15 years)
You have a grid meter to see if there is surplus/feed-in and you can use that information to switch on a relay.
If there is still more surplus/feed-in â switch on the next relay.
If you tell the GX device how much power each relay activates the GX device can dynamically switch on/off the relays.
Something like that should be the first step IMO.
Adding more complexity with energy meters can be the next step.
Hey @M_Lange, if you only care about ESS where unrestricted feed-in is allowed, then it can be as easy as that. And thatâs what most of our competitors do. But GX Opportunity Loads is really designed to work under all conditions of a Victron system:
- ESS with unrestricted PV feed-in
- Restricted and zero feed-in systems
- Considering âper phaseâ vs âsum of all phasesâ grid metering
- And especially: Systems without grid connection
To make the right decisions when multiple devices are involved â avoiding unnecessary battery or grid consumption, preventing per-phase inverter overload in off-grid, and maximizing the use of available surplus â continuous real-time power measurements of all controllable loads is the only way.
And, being a software engineer, I can tell you that going from simple to complex is exponentially more work than doing it the other way around 
Are there maximum values in seconds that are being enforced in the Opportunity Loads > Device > Minimum Run/Rest?
For instance I can set 600s for 10m or 900 for 15m but are there limitations? If I say want 30m (1800s) or 4hrs (14400s)?
I wouldnât mind just a check box for enable/disable, if excess solar is available, regardless of what it is consuming. e.g. I donât mind if a device can use more than the excess available, to a certain extent.
i wanted to see what is possible at the moment already - but in my system - newest Beta installed - i don´t see the Opportunity Loads Menu
Is there any special hardware needed?
One Shelly Plug S is activated at the moment
It showed in mine under Settings > System Setup
I was digging a bit and eventually found it.
Manual is quite good.
I realize that youâre trying to do something generally applicable (hence the requirement for power measurements of loads) â but on the other hand I know that quite a lot of boats are using the same method for immersion heater switching that I am (ACOUT2 controlled by assistants or node-Red), and it would seem an obvious improvement to bring this into the Opportunity Loads program without requiring them to needlessly buy and fit a Shelly, especially in a hardwired systemâŚ
Mind you, Iâve just checked and a Shelly 1PM Mini Gen3 is only about ÂŁ15⌠
i tried it in another simple system i have remote access - it showed up
but not on mine - strange
Maybe because i have no officially supported PV inverters ? i integrated them with a DBus-Script
Not sure how this will work, but it is a great problem to solve. Need to turn on desired loads when conditions are right, but then optionally let them complete even if the sky darkens. This is important for loads like laundry or baking where EV charging might be on an as available basis.
Hi @kr0815, itâs likely related to the modifications you made to your system. You can do the following to verify it: Go to Settings > General > Support status and click âDisable and reboot nowâ.
Thanks Philipp, but then i´d loose my dbus-serialbattery
Not worth at the moment to just have a look
Sure, I understand that.
As a general note: GX Opportunity Loads can run on a modified system. Itâs just likely that the modifications are the reason why itâs not working for you.
to get a better understanding:
What is neccessary / has to be fullfilled so that this menu point shows up?
Maybe the problem is that my existing Shelly Plug S is already used by NodeRED?
The menu item under System setup should always be visible on supported GX devices from Venus OS v3.80~27.
Hi @natewin, there is no hard maximum limit. But I would question if a setting longer than a few minutes does make sense. The setting is there mainly for things like:
- Prevention of frequent on/off due to fluctuation in solar power
- Assure a minimum startup or run time, e.g. when controlling a heat pump.
Yes, exactly. Our aim is to provide a solution that requires minimal configuration while providing reliable results regardless of the setup. And yes, Shelly devices with power measurement are really not that expensive. Anyways, the recommendation is noted down and we will check if itâs something that can be considered for a future version.
