Thanks for all the advancements and making it possible to use the RS solar for DESS. I’ve been using a three phase system now for about a month or so and overall I’m very pleased!
I did want to ask though about the behaviour in trade mode:
With my old system using multiplus units the battery would only charge during lowest prices and ignore pv production before and after that, allowing it to be sold for a higher price (between 9 and 12 in the morning for instance).
Since installing the Multi RS units I see the above behaviour a lot: it tries to catch as much pv production as possible, even though the pv currently is AC connected and selling it would make more sense in trade mode. (I’m planning to put pv directly on the RS system in our new home that is currently being designed, that’s why the PV is currently only AC coupled)
Can anybody comment on this behaviour? Is the Multi considering any pv in the system to bd DC coupled an thus deciding to rather put it in the battery than sell it?
Another strange thing I have been noticing now a couple of times is this: after fully or partially discharging the battery during the evening price-peak, about 15 minutes or one hour after stopping the discharge, DESS suddenly decides on a much higher desired SOC and immediately starts to recharge the battery, this happend at least 2-3 times the last weeks. One of these instances happened on the 2nd of may in the evening. (discharge ended 22:00, charging suddenly started at 23:00 although this was not previously planned, and not at a favourable time).
Any thoughts on this one?
My site number is: 402251. I hope my feedback helps to further improve the system!
Just to add to the above: the second behaviour has just happened again, started at approx. 23:30. DESS suddenly decides to go from desired SOC of 41% to 45%. Any ideas why this is happening?
Today DESS either overshot the discharge target or suddenly decided on a higher desired SoC, different graph, look at the far right, the bottom dot shows the reached discharge state, the top dot the target and the middle dot the current SoC:
This proves that DESS is suddenly deciding on a different SoC, even though no new price information became available (as far as I can see). One hour earlier DESS was planning to discharge to 5% (my minimum) between 00:00 and 01:00 during the night and do a full recharge the next day during low prices. Now it suddenly wants to go to approx. 46% and stay there until the morning. I don’t understand this and it is bad trading since the price differences were more than adequate to discharge to the allowed minimum and start a complete charge the next day.
At this point I disabled DESS… Will re-enable it in the morning.
Today I have some more examples of odd (dis)charging behaviour. After charging to 100% DESS was planning to wait 2h before discharging. It started discharging one hour early though, then pausing the next hour, where prices would have been higher.
There are two reasons I can think of that could lead to this behavior. The first would be that the system has overshot its target. Or, to put it another way, the charging and discharging parameters aren’t set correctly. I’ve had this problem several times with my own system. The second reason, and this is what I suspect in this case, is that the weather forecast changed during the process. This correction within certain intervals is often a great advantage of the DESS, but sometimes it turns into a disadvantage.
Use lower parameters for the system, if these are not set to the systems actually capabilities will be off target. I set the system up without solar connected 1st and tweek settings for a few days, then introduce solar when discharging and charging rates are nice.
