regen on long downhills

regen on long downhills

I have a 2018 Model X 100D delivered early Dec 2018. we have frequent trips from Denver home to Winter Park home. On long down hill runs in temps ranging from -20 degrees F to plus 93 degrees have times lasting from seconds to a few minutes when regen is limited usually but not always with the yellow triangle ! sign. usually after curves but can occur on long straightaways. In Winter I thought maybe battery was getting cold. now wondering if regen generator is overheating. anyone else notice this or have ideas of cause or a fix?..if necessary.

mbirnie51 | August 5, 2019

First, you must start your trip with a conditioned battery pack (BP), by that I mean at optimal temperature. Second, you must only have approximately 80% charge on the BP to get full advantage of regen, and third, you must set your regen to STANDARD to see maximum regen.

So, if you start out your trip with a cold BP at any level of regen; if you start out with warmed BP and 90 to 100% regen; if you start your trip with a warm BP and 80% charge but REGEN set to minimum...very little regen. These conditions of BP is true for all outside temperatures.

Bobblec | August 5, 2019

Sorry. tried to be brief. heated garage, warm battery pack. often charged to 90 % but have full regen up and over pass then briefly reduced as described. always on standard regen and in chill mode. again occurs in both hot and cold seasons, like today at about 90 degees--no cold battery here. regain 12 to 18 miles in trip down, but would be more if not reduced regen. how is this inappropriate? it is a real experience.

mbirnie51 | August 6, 2019

Other than starting out at 90%, I can't see anything that would keep you from getting optimal SUPPORT with your concern using as much detail as you can with ODO readings if you have them. With odo reading they can zero in on your vehicle to see if it is functioning as designed regarding your concern. Operators note: If you press and hold the sterring wheel "TALK" button and first say "BUG REPORT" while you lack regen, then your concern it also goes to Support with your odo reading, logging it into your file for alert to service.

I have had some success sending emails to Tesla Support. They answer me next day with somewhat appropriate answers. These emails also go into your file so the next time you go to a Service center, it will be documented as a concern.

On one trip I left Silverthorn with a 75% charge and got down to Denver with +20 miles regen, more than enough to get to Limon.

David Trushin | August 7, 2019

Limitted regen often continues for a number of miles after the indicators go away. My guess is that the threshold for when the indicators go off is the same as or close to the low regen level. I.e. regen limit indicators stay on until the system is regenerating as if in low regen, then they go off but the car increases regen to the standard level. There I'd also a max charge limit on regen so if the charge exceeds this it goes back to limited. At what charge level do you see limited regen come on? It should be somewhere around 290 miles of charge plus or minus 5.

Bobblec | August 7, 2019

Thank you all. I will first do the bug report next time. one last thing to add is usually charge with silver wall charger at WP for home trip to balance more supercharger charges and in the Winter be sure to have heat if accident delay on way home--90 %, but % in summer then often only need early Sat AM charge for typical week. also start Denver bound trip with 2400 climb over 13 miles. Appreciate the thoughtful ideas.