Driverless Cars

[prof fate]

Apple car...where they are/will be - what the future options are...

What's up with the Apple Car?! - YouTube

 

[3930dave]

Heating of the EV is not a problem because of the motor(s) and possibly some of the electronics are liquid cooled. In other words there is a waste heat available for heating.

Possibly in some geographies, but not in much of Canada...... just not enough waste-heat available, to melt even an 1/8" of ice on a windshield.

Rgds, D.

 

[Gale Hawkins]

Maybe they will go back the the propane heats of the VW era.

Actually there will always be environments that may rule out year round use of EV's. A Subaru Forester with the winter package sounds nice for winters where you have winter 10 months out of the year.

 

[prof fate]

That's my concern - winter and batteries. Battery capacity always drops in the cold..so what is the range when it's 5F outside? Add in use of lights (winter is dark more than light), wipers and defrosters, interior heat - and then the juice to drive.

I see a MPG drop of 10-20% in the cold/winter months. I suspect it is greater with an EV. What, 50% perhaps? that cold be an issue. I've read nothing about this winter use...

Maybe they will go back the the propane heats of the VW era.

Actually there will always be environments that may rule out year round use of EV's. A Subaru Forester with the winter package sounds nice for winters where you have winter 10 months out of the year.

 

[Jstpssng]

^^^^
I've been asking in various places about lights, heat, and wipers for several years now but have yet to get an answer.

 

[Jchonline]

That's my concern - winter and batteries. Battery capacity always drops in the cold..so what is the range when it's 5F outside? Add in use of lights (winter is dark more than light), wipers and defrosters, interior heat - and then the juice to drive.

I see a MPG drop of 10-20% in the cold/winter months. I suspect it is greater with an EV. What, 50% perhaps? that cold be an issue. I've read nothing about this winter use...

EV is a bit tricky. The discharge rate in cold weather is markedly worse, at least of the types of batteries Tesla uses. Keep in mind there may be ways to mitigate this with other technologies. The current Model X was discharging at double the rate (ie 1/2 the mileage) in 30F. I cant imagine how bad it would be at -15F.

 

[3930dave]

Yep, even 3 months of heavy Winter weather is enough to convince most people of the value of hydrocarbons.

I tend to do my long trip drives in the summer, as most do. Running out long like that, I'll often have at least one full can of extra fuel with me.

It was -25C here this morning. Road closures do happen, for various reasons..... I hate to think about being stuck (on-road, or off), watching the battery voltage that I depend on for heat dropping.....

Heavy Winter clothing/gear in every vehicle is a good idea here...... doubly so in an EV.

Rgds, D.

 

[3930dave]

Yep, even 3 months of heavy Winter weather is enough to convince most people of the value of hydrocarbons.

I tend to do my long trip drives in the summer, as most do. Running out long like that, I'll often have at least one full can of extra fuel with me.

It was -25C here this morning. Road closures do happen, for various reasons..... I hate to think about being stuck (on-road, or off), watching the battery voltage that I depend on for heat dropping.....

Having heavy Winter clothing/gear in every vehicle is a good idea here...... doubly so in an EV.

Rgds, D.

 

[vvanders]

EV is a bit tricky. The discharge rate in cold weather is markedly worse, at least of the types of batteries Tesla uses. Keep in mind there may be ways to mitigate this with other technologies. The current Model X was discharging at double the rate (ie 1/2 the mileage) in 30F. I cant imagine how bad it would be at -15F.

It's actually much less to do with discharge rate of the pack. There's a ton of thermal management to keep the LiIon banks in a happy state(since when they're out of spec it speeds degradation, see why your smartphone capacity drops). Plus under active discharge they tend to generate heat offsetting the cold.

There's basically 3 impacts to winter driving, in order of scale:

1. Dense air. V^2 gets brutal, and even more so when you're talking highway(60+ speeds).
2. Resistive heating is incredibly inefficient, you can mitigate this by warming while charging but def a hit.
3. Colder tires have less pressure and stiffer leading to higher rolling resistance.

I used to do a lot of driving year-round including once a week 300mi roundtrip in a day. When temps started dropping below 30F I'd see a ~30% impact in range. Definitely noticed it but wasn't an issue along my route as there was plenty of HVDC charging. Usually added ~10 minutes to the trip for a quick top-off about 50mi from home or so(packs charge much faster at low capacity).

 

[3930dave]

It's actually much less to do with discharge rate of the pack. There's a ton of thermal management to keep the LiIon banks in a happy state(since when they're out of spec it speeds degradation, see why your smartphone capacity drops). Plus under active discharge they tend to generate heat offsetting the cold.

There's basically 3 impacts to winter driving, in order of scale:

1. Dense air. V^2 gets brutal, and even more so when you're talking highway(60+ speeds).
2. Resistive heating is incredibly inefficient, you can mitigate this by warming while charging but def a hit.
3. Colder tires have less pressure and stiffer leading to higher rolling resistance.

I used to do a lot of driving year-round including once a week 300mi roundtrip in a day. When temps started dropping below 30F I'd see a ~30% impact in range. Definitely noticed it but wasn't an issue along my route as there was plenty of HVDC charging. Usually added ~10 minutes to the trip for a quick top-off about 50mi from home or so(packs charge much faster at low capacity).

Good data.

Looks like your Dec - Feb avg Low Temp is around 31F, with avg snowfall of less than an inch.

Another significant Winter energy burner relates to the road surface. Slippery conditions waste energy with spinning wheels..... doesn't sound like much until you crawl along in traffic for 30+ minutes.

Then there's pushing through snow on unplowed, or just not recently plowed, roads. For many Canucks, that's not just a remote rural issue....... I've driven major roads in Toronto that were full of 6"+ inches of heavy dense snow <- doing that kind of driving takes a ****load of energy.

The above conditions are a Don't Care, if you don't have to deal with them, but for some of us, the Range Anxiety associated with those type of conditions is the Real Deal.....

Rgds, D.