What Happens When the Traction Battery Fills Up?

Thanks for the correction. I noticed the engine braking in D, but did not check to see if it was greater in B. I drive plenty of hills, but haven't had many of the extended low speed hills to worry about brake overheating yet.

 

When driving my car and hitting a few lights after a long 65 MPH commute, my car seems to switch to engine braking in the middle of a slowdown as it isn't totally smooth. Anyone else notice this? I live in Florida without hills but I drive a 10 mile or so stretch of road at 65 MPH and that will usually fill my battery pretty well and then I go back into town and hit a couple lights which seems to fill my battery all the way up. Usually upon hitting the second light, my engine seems to kick on and act as the engine break once my battery peaks out. Anyone else notice this.