- If I'm barely touching the acclerator is it still regen braking? cause I can definitely feel the car still slowing down really fast if I'm barely touching accelerator.
Yes. Green bar under the speedometer is where it's at if you really want some quantification of regen (note the scale is
extremely nonlinear, though).
- If my max % is set to 80% and I drive all down hill to work, is the car really regenerating any electricity?
Yes. It'll go over the max as others have said. (Last I checked it appears to add range in 3-4 rated mile chunks (probably 1kWh, or maybe 1%?), though obviously it's actually doing it continuously; there is some quantization/hysteresis.)
If you are finding that your car complains about limited regen at some point on your descent, set your nightly charge level to a lower level. Otherwise don't worry about it.
It's quite common at 80% charge level in warm temperatures, with a battery that has been sitting, for the car to limit regen AFTER you regen substantially on a large hill (so regen will be rapidly reduced as you regen more). (This is presumably to prevent any lithium plating since the reincorporation of the lithium is probably rate limited. Speculation.) This will be both noticeable from a braking perspective, and it will be
audible. When it starts happen, the car appears to switch to heating the battery (you start to hear a sound similar to the pre-conditioning for a Supercharger - motors become quite whiny). I don't have TeslaFi to confirm this stator warming, but it would make sense that the motors switch over to a less efficient mode (it's only a few kW so you won't notice it in braking power - but it will improve "regen" braking slightly (it would be a combo of battery heating and regen at that point)) and heat the battery in an attempt to restore more regen, rather than heating the brakes. And audibly that appears to be what happens. Speculation.
Anyway, details; if you're not having limited regen messages and you're not using the brake at all, you're doing the best you can, and you should just forget about it. The solution if you have that issue is to lower your SOC as mentioned. The optimal situation (for "slosh losses") is to
minimize both acceleration and regen, with zero use of the brakes (it's a little more complicated than that for overall efficiency since speed also matters).