Wrong energy calculation when driving through tunnels

Wrong energy calculation when driving through tunnels


I drove during the last weeks lots of kilometers in the Swiss Alps using tunnels and always saw the same error on the "Trip" page of the "Energy app": at the beginning of the tunnel the planned energy graph indicate an higher energy consumption, a peak at the middle of the tunnel and an energy gain from the middle to the end of the tunnel. I understood that the computer use the altitude of the mountain situated above the tunnel instead of the altitude of the road in the tunnel. At the end, there is a light difference (on the good side) between the planned and the used consumption.

Has anybody noticed the same problem and how can I inform the Tesla developpers to fix this bug ?

Greetings from Switzerland !

Alain | 17 août 2015

I don't believe there is any issue. The energy graph is using the actual energy used by the car. It doesn't adjust this for altitude or anything else.

It seems likely the tunnels are slightly higher in the center than at the ends, which would match the results you see. This may be done to avoid flooding in the tunnel (i.e. water runs out rather than collecting in the center).

rxlawdude | 17 août 2015


DTsea | 17 août 2015

Teslatap OP is referring to projected energy use graph. Not actual.

alain.von_bueren | 17 août 2015

TT I am not understand with your answer. I said planned energy graph and not actual. The tunnels I drove through where about 2 km long and always in a steady climb. The planned use energy showed a steep V shape (huge loss and good recuperation) but the actual showed a steady loss, exactly according the actual path in the tunnel.

That is really a bug I guess ... | 17 août 2015

I had to go out to my car to confirm. There is no projected energy use graph. The graph is always actual energy used. There is a projected range number and perhaps that is what the OP is talking about? I'm still doubtful altitude is used in this projected range number, but I have no way to confirm it. I was fairly sure it only used the prior energy usage to project future range.

This is different than navigation, which now uses altitude to determine if there is enough range to get to your destination. | 17 août 2015

Curious, I had to look in the car again. I'm wrong. I was looking at the Consumption Tab, which is only the exact energy used. Sorry for doubting you!

I forgot about the Trip tab which is the projected energy while using navigation. I agree that this likely uses altitude in it's analysis. It does sound like it doesn't use actual road altitude, but uses physical altitude. If true, the altitude works fine except for tunnels, and I suspect bridges too.

This may be very difficult to fix, as the data for actual tunnel/bridge altitudes might not be available from Google or Garmin. Still it is worth notifying Tesla of the issue.

To let Tesla know about this, send the info to Tesla at:

JohnHarte | 17 août 2015

I think Bjørn mentioned this in one of his videos. The projected energy use is for driving over the mountain not through it..

tes-s | 17 août 2015

I agree it is probably inaccurate, but not material in the overall accuracy of most trip estimates. My guess is if road altitude was used the overall estimate would be slightly lower.