Alarming Energy Display Following Body Shop Visit

[berkeley_ecar]

My 90D got grazed in a parking lot, and spent 31 days in a Tesla-approved body shop for repairs. The day I dropped it off at the shop, I noticed a short time later (in the nearby car rental agency) that my iOS app could not connect to the vehicle; I called the shop and they explained that they always immediately disable remote access to prevent someone from causing a mishap (by opening the rear hatch at an inappropriate moment, for example).

When I picked my Model S up two evenings ago, I was startled when I first placed the vehicle into drive, as an energy display with an alarming yellow warning triangle appeared, unbidden, for a brief time at the right of the driver's console (image 01_Dash_warning.jpg). I put the car back into park and pulled up a full energy display on the MCU (image 02_energy_5mile.jpg shows the usage for the past 5 miles, summarizing most of the 6 miles it was driven while in the shop). I also displayed the energy usage for the past 30 miles, showing my usual energy usage pattern preceding the shop visit (image 03_energy_30mile.jpg). The next day I displayed an update for the 30 mile data (image 04_energy_next_day.jpg).

The huge spike in energy consumption shown in the 2 miles prior to my pickup could perhaps represent some totally benign artifact related to the service visit, but I'd feel happier if I had a good clear explanation. Obviously, I am hoping it does not represent some sort of abuse of the vehicle. Before taking it up with the shop next Monday, I thought I'd ask if anyone had seem something similar, or perhaps had a knowledgeable explanation. Please -- let's stick to well-founded information and avoid wild speculations in this thread. My thanks in advance for any useful thoughts.

 

[Sorabh]

I have noticed spikes like this when I run climate for a while and then drive. It shows astronomical rates then flattens out after a few km's

Hopefully that is what it was.

 

[bmah]

The first picture is what you could expect to see if your regen is limited by cold temperatures or a full battery. No comments or opinions on the other screens.

Bruce.

 

[croman]

I have noticed spikes like this when I run climate for a while and then drive. It shows astronomical rates then flattens out after a few km's

Hopefully that is what it was.

That's exactly what it is. Running heat without accumulating miles.

 

[75Shappyt]

Bruce is right,

 

[berkeley_ecar]

Ah, both of these explanations make perfect sense. I drive in a moderate climate (and hence have no need for cabin pre-conditioning), and only charge above 90% when departing shortly for a long trip (so very rarely get into situations where my regen is limited), so have not observed this behavior before. It's probably not the regen. explanation in this case, as the state of battery charge was under 90% (I was remiss in not including the state of charge in my original description of the problem). This also suggests to me that the energy display could be improved by factoring these effects into the presentation of information in the graph: the vehicle knows when it is using HVAC and not in drive, and also knows when regen. is limited. Many thanks for the helpful comments.

 

[TMeister]

Before taking it up with the shop next Monday, I thought I'd ask if anyone had seem something similar, or perhaps had a knowledgeable explanation. Please -- let's stick to well-founded information and avoid wild speculations in this thread. My thanks in advance for any useful thoughts.

Ok, I'll speculate. You should ask for the dyno plots the shop ran while they had the car.

RE: the other speculations that cabin heat does this... I use cabin heat every day in our winter climate. Usually 15 minutes prior to getting back to the car. My energy display never shows such behavior. The car heater only consumes on the order of 5kW. And why would cabin heat be on in Berkeley anyways? Gotta be in the 50s or higher.

 

[drklain]

My experience after service and when my car was in the body shop for several months was that I saw something similar. My theory is that this is because the chart is showing all energy used over a given distance and does not discriminate for time. When a car is in the body shop for weeks without moving, even vampire drain usage, combined with powered up time when a door or doors/hatch are open leads to power usage. The result is that the car may lose more than 50% of charge while in for that extended repair period (Took my car in at just under 90% charge, got it back from body shop 8 weeks later at 20% charge.

The energy usage chart puts all that usage against zero miles traveled (or 1 mile) and it gives you a spike in energy usage that promptly goes away once you've driven 30 more miles. My guess is something similar happened to your car (and happens to all Teslas).