ECR is a fluctuating player statistic that limits the amount of Dark Energy Crystals that can be earned for a given Ranked battle.
A player's Energy Capture Rate (ECR) gradually diminishes every time they play a Ranked battle, then regenerates with time.
When ECR is full, it is at 100%. The average battle will cause the ECR to be reduced by about 1%, which can cause ECR to drop significantly when many battles are fought in a single sitting, resulting in reduced DEC earnings per win.
ECR regenerates at a rate of 25% every 24 hours, or 1.04% per hour. To maximize your potential DEC earnings, it is recommended to play no more than about 25 Ranked battles per day.
At 50% ECR, you will earn exactly 50% of the Dark Energy Crystals you would earn if your ECR were at 100%.