Tesla Motors Club

I have a Tesla Mode 3 long range 4WD for a little over a month and charged it primarily in the garage and didn't have any problems. However, all my experiences charging at superchargers (3 times so far) revealed a slower than expected rate: no more than 40KwH which makes Tesla a barely usable during long trips. I am still not sure: is something wrong with my car; was I unlucky to charge at faulty or not fully functional stations or something else. The charging conditions in all cases were normal: at least 50 degrees, fully warmed car at 20-50% charge, not overcrowded charging stations.
All my attempts to find from Tesla technical personnel how normal it was ended up with non-committal assurances that charging rates vary? how much? they would not answer. I visited a Tesla dealership in Chicago downtown anticipating that I could compare my car charge rate with one that is already there. no luck: they claimed that their stations are old and slow and I would not see much difference. I have a few questions hoping that this forum could help with:

1. How typical this experience is, are my expectations that are under normal circumstances the charge rate ion 135kwh stations should be close to 120kwh which should result in 30 minutes charge for my long range model 3 from 10% to 90% charging
2. What rates people usually observe
3. How to verify that it is not my car fault
4. What pressure I could apply to Tesla to check the car

The other issue: the discharge rate on highways is about 30% faster than the car predicts. I realize that battery depletion depends on many circumstances but I would at least expect that software would detect the existing rate and adapt predictions accordingly. Otherwise, it is an outright unreliable number that one should correct in their head predicting how far she could go before a battery is dead. By exaggerating charge time and underestimating the discharge rate, Tesla plays the way all automakers do. I hoped they would be different for the sake of trust and a good customer relationship. A little disappointed although driving itself and car handling is a lot of fun.