The most misunderstood aspect of the Toyota hybrid synergy drive system

Well, I found my cruise control applying about 13 kW of regen, as I went down a particular hill in Indiana.

I'm pretty sure if I had canceled cruise and pressed the brake pedal, more than 13 kW of regen would have happened, up to whatever the power management control ECU was reporting for the charge control value at that time. The gen 3 repair manual gives a normal value for that as "−33 kW or more" (where they're saying "more" because it's a negative number, so, for example, −27 is 'more" than −33). The ECU can adjust the charge control value to "more" (i.e., gentler regen) if it finds the battery to be hot or tired.