Model S Boston Winter Driving Wish List

[PeterK]

Great subject!

I would like to see an option to not heat the battery during short trips. I'd rather have an option to accept a reduced power limit.

i've recently averaged ~700 wH/mile for a 4.5 mile trip in 14F weather. And, this was just a 60kWh vehicle. That's equivalent to achieving 41 mpg. I estimated at least 1.8 kWh to heat the car for this short low speed trip (700wH/mile-300wH/mile)*4.5 miles = 1.8 kW. If you averaged four such thermal cycles per day, this would be equivalent to driving an extra 24 miles per day at the normal 300 wH/mile. I would expected that the 85 kWh folks might experience 42% greater energy to heat their batteries just scaling on battery cell weight (Equivalent to driving an extra 34 miles per day) ! Sure some of that goes to climate control, however heating a 900 lb battery likely takes far more energy than heating the air and upholstery of the interior. I love my Tesla, but this inefficiency must be fixed before widespread adoption in northern climates.

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I'm taking some time off and doing lots of short school dropoff/pickup runs in this cold weather, and my lifetime wH/mile is steadily climbing as a result. Not the kind of mileage I want to see. There is no point in heating the battery much for a 2-4 mile drive at 35mph max.

 

[Enadler]

Great subject!

I would like to see an option to not heat the battery during short trips. I'd rather have an option to accept a reduced power limit.

i've recently averaged ~700 wH/mile for a 4.5 mile trip in 14F weather. And, this was just a 60kWh vehicle. That's equivalent to achieving 41 mpg. I estimated at least 1.8 kWh to heat the car for this short low speed trip (700wH/mile-300wH/mile)*4.5 miles = 1.8 kW. If you averaged four such thermal cycles per day, this would be equivalent to driving an extra 24 miles per day at the normal 300 wH/mile. I would expected that the 85 kWh folks might experience 42% greater energy to heat their batteries just scaling on battery cell weight (Equivalent to driving an extra 34 miles per day) ! Sure some of that goes to climate control, however heating a 900 lb battery likely takes far more energy than heating the air and upholstery of the interior. I love my Tesla, but this inefficiency must be fixed before widespread adoption in northern climates.

My understanding is if you keep the HVAC on Range then the battery warmer does not kick in. I never get the message Battery Charging when in this mode even when the temp was below 10 degrees and regen was severely limited.

 

[Robert.Boston]

My understanding is if you keep the HVAC on Range then the battery warmer does not kick in. I never get the message Battery Charging when in this mode even when the temp was below 10 degrees and regen was severely limited.

That's right. On the Controls/Settings menu, change Range Mode to "ON". The HVAC will now show "Auto Eco" (or "Custom Eco"). The battery heater will not kick in.

 

[seanmccutchan]

That's great to know! I'll give that a try tomorrow. Perhaps that should be default, or at least more obvious. I can see lots of potential confusion over this for the "turn key" user.

 

[PeterK]

That's right. On the Controls/Settings menu, change Range Mode to "ON". The HVAC will now show "Auto Eco" (or "Custom Eco"). The battery heater will not kick in.

Ironically, I had left it in range mode after my last trip but went back to normal because I read that it would preheat the battery on shore power when heating the cabin via the app. But I guess I really don't need to heat the battery much anyway for such short runs.

 

[Robert.Boston]

FWIW, I find it really annoying to drive without regen. The car feels incredibly heavy, having to use the friction brakes at every speed-bump and 4-way stop that litter central Boston. If I've got my brain engaged, I leave the car in normal mode when plugged in, to get the battery heated from shore power, but then flip it over to range mode on battery to disable further heating from battery power.

 

[PeterK]

FWIW, I find it really annoying to drive without regen. The car feels incredibly heavy, having to use the friction brakes at every speed-bump and 4-way stop that litter central Boston. If I've got my brain engaged, I leave the car in normal mode when plugged in, to get the battery heated from shore power, but then flip it over to range mode on battery to disable further heating from battery power.

That seems the best solution, Robert. It would be nice to have a setting that automatically did that.

 

[Enadler]

That seems the best solution, Robert. It would be nice to have a setting that automatically did that.

Actually I think this is a programming design floor. It is would be much more efficient if the program would engage the battery heater when the car is preheating and attached to shore power regardless of whether or not range mode is engaged.

 

[Doug_G]

Agreed, but only because I've found some thin leather gloves that still work with the touchscreen.

I have yet to wear gloves in the car this winter. I lost one of my gloves and haven't bothered getting a replacement. The steering wheel doesn't feel that cold even when it's cold in the car.