We start from a dataset describing the energy delivered and received by the battery.
There are no "proper" round trips, which go from 100% charge to 0% and then back to %, and would allow us to directly compute the Round-trip efficiency (RTE).
Since we do not have round trips, we estimate the RTE from the next best thing:
segments of the State-Of-Charge curve that start at a local maximum, discharge and then recharge reaching the original SOC.
We call such segments trips:
Eventually, using the data in BESS_op_data.csv:
Average RTE over 16 trips = 86.33%
Average RTE over 16 trips (weighted by each trip's Δ SOC) = 86.27%