Babysitting our ex 06 Civic Hybrid for a bit. The hybrid battery (replaced about 6 months back) seems to be performing fine, going up and down through the upper half of range uneventfully, good! Then I started fiddling with the vent mode, set it to heat/defog. A few minutes later, noticed no green bars (regen) when going downhill, applying brakes. Some consternation. Then something in memory clicked, I set it back to Auto (and switched AC off). Green bars immediately reappeared. Set it then to High/Low mode, still ok. So: Heat/defog seems to lock out regen. I guess that's by design? Can't remember.