I have a 3 phase system (3x MultiPlus-II 48/6k5/100-50) with a 32 (2x16) KwH battery behind it.
Yes i know, maybe a bit much for just 32 KwH on battery, but it was installed so that i could expand on battery capacity later without having to upgrade everything…
Over the last few days (with high electricity prices throughout the day I noted that the system does not optimise correctly.
For example yesterday it pulled 45.2 KWH from the grid (and got 2.1 KWH solar), of which my own consumption was 12.9. It delivered 19 KwH back into the grid and battery SOC went from 11-39% ie. 28%32 Kwh = 8-9 KWh into the battery. that means 45.2+2.1-12.9-19-8= 7.5 kwh own use. With a lowest buy price of 38 cts that means 0.38*7.5 = about 3 euro in ‘operating cost’.
I with a high sell price of 48 euro cts I earned 10*19= 1.9 euro which means thessytem ran at a loss.
Of course,if it hadn’t stored power out of the grid and pushed it back in, it also would have burned some energy and hence there is also a cost to idle, but I hope you get the point. Reading the topics, this might have to do with the DES efficiency factor (which indicates to the system how much energy it will use for storing and selling a KWH. mine currently stands at 90% in the system. but given the fact over the last months the systems own consumption is 25-30% of the amount that is delivered to the grid, i get the feeling that my DES efficiency factor might be too high (which means the system thinks less energy is needed (and hence less cost are incurred for running the trade.Am I correct in this assessment and if so, given the figures above, what DES efficiency factor should go into the sytem for the system to realise it operates at a loss.