I have 8.5 kWp PV and a relative huge battery of 56kWh.
When using DESS green mode I expect the system to optimize for self consumption, e.g. only sell that energy that does not fit into battery.
Or try to recharge to 100% SOC during the periods of knowing prices (12-36hrs)
Currently, DESS tries to sell all energy hat highest selling price down to “min SOC”.
This decision is not optimal, if PV is less than consumption after periods of known prices.
The variable minimum discharge SOC should be equal
100% SOC - PV prognosis + consumption prognosis
In my case I have fixed buy price of 39ct/kWh and variable sell price from -5 to + 25ct/kWh. Though selling PV energy and buying back from us suboptimal in any case.
Currently I switched off DESS as my SOC varies between 25 and 80%.
That is indeed, what it is supposed to be - plus a small “uncertainity buffer” actually.
I will have a look at your schedule this evening. I think something irratical may happen due to the “flat” buy price. Don’t have an idea right now, but flat prices already caused strange behavior in other cases as well.
Thanks a lot.
I switched on DESS appr 19:45 today so you can analyze.
The scheduler immediately started discharging the battery.
Within the timeframe of knowing prices until tomorrow 14:00:
SOC will never reach 100%, max is 83%
sell price will never exceed buy price
at the end of schedule SOC will be equal min SOC (50%)
My observation:
DESS schedules to sell as much as possible as long as “min SOC” is not violated.
In this situation ”buy price exceed sell price at every slot” I would expect:
sell as less as possible
plan max SOC around 95-98%. Keep buffer of 2-5% for wrong predictions.
You can switch on and off DESS if you like for you analysis. Just drop me a message whenever you finished. Please do not adjust max battery power as I have to change some fuses to support more than 200A on DC permanently. Bottleneck is the connection between battery shelf and Lynx Distributor connecting the three MP2 5K.