I have mentioned this here and there, but I’ll create a separate feature request as today is a very good day to demonstrate why this could be useful.
My solar array can produce way more than can be stored in the batteries, and the sell price during the day often drops to zero or negative. So DESS switches off MPPTs when batteries are full, and a lot of potential solar energy is wasted. This is where opportunity loads would help. Things like heating water in the DHW tank or running an electrical heater if it is autumn, could be potential loads.
As you can see in today’s schedule, it is predicted that at about 14:00 batteries will be full and the sell price is 0, so quite a lot of solar will be lost.
Good implementation would be when loads are switched on in advance, not just when the batteries are full, because maybe my configured loads can’t cover peak solar production so loads could then be distributed evenly during the day. DESS knows how much solar is predicted after 14:00 so it can easily calculate when to switch the loads on. Maybe even show those in the graph as a separate color named “Solar to Opportunity Loads” (both actual and forecasted).
i’m having a quite similar situation: During summer, I have more solar than my battery can take and with dynamic feedin, feedin during the day is just not worth it or even negative.
So, not sure if you are referring to “Opportunity Loads” as a general term, or to “Opportunity Loads” as in the feature released with Venus OS 3.80?
But for the later, you can achieve what you describe, I do it like that as well:
My Opportunity Loads has control above roughly 18kW consumers, including the EV - and with a simple Node-Red Flow you could disable DESS in the morning and enable Opportunity Loads.
Needs a bit of playing around with OL-Settings, for me starting loads at 30% Soc and issuing a battery reservation of 8000W at that time (goes down with every % soc gained) always worked out to reach 100% soc (70 kWh) at evening while heating the pool, charging the car, and several smaller loads and close to 0 feedin.
Watching Opportunity Loads OperationalState turning to SleepMode (i.e. no more solar detected to drive any additional load) is a suitable time to switch back to DESS for selling in the evening as this means all Opportunity Loads have been turned off again.
Morning. I’ve been working on this approach for years too, using Victron’s built-in relays. These include the Cerbo’s generator relay, as well as the relays on the three MP2s. It doesn’t work on the basis of forecasts, but instead responds to the situation. I don’t want to explain it in detail, as it’s different for every user. As long as the battery’s SOC is below 30%, all the energy goes into the battery. Above that, loads are switched on when the battery’s charging voltage exceeds a certain level. From 2 pm, the generator relay switches to “quiet mode” and only switches on loads once the SOC exceeds 85%.
