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The cold hard truth about electric vehicles in winter

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Re: The cold hard truth about electric vehicles in winter

#21

Post by ajross »

Tostino wrote: post #2

That is interesting to see the difference the manufacturers bake into their battery designs as far as software control goes. Tesla seems to quite tightly control pack charge and discharge through their bms, and limit things in software rather than hitting chemical limits of the batteries like some other manufacturers seem to be allowing.

It's not a chemical thing, it's just temperatures. Cold batteries have lower cell voltage, so the current available drops into the non-linear ("off") range at a lower state of discharge than a hot battery. The energy is still there[1], you just can't get it out without warming it up.

Teslas[2] (and a handful of other models) have heat pumps to warm the batteries. It's as simple as that. The same system is integrated with navigation too, because even on warm days unused/empty cells will be colder, and you want those to be warm when you reach the supercharger.

[1] Which is to say this isn't strictly a change in "range", if you can drive somewhere warm you can keep going to the rated distance.

[2] Ones built over the last three years anyway -- older ones didn't have this. I think Y's and all but the oldest 3's have heat pumps, but older S/X models might not. Something to be aware of when buying on the used market.

Re: The cold hard truth about electric vehicles in winter

#22

Post by rightbyte »

linsomniac wrote: post #9

Range impact of cold weather does seem to be a real thing, I can't speak personally because I own a Tesla which has some of the lowest impact. Another thing to keep in mind is: Charging speeds of cold temps. While the Tesla seems to do great at range, charging at cold temps is not great. When it's below freezing, home charging can be tough to impossible. A few days ago (when it was merely "cold", before the huge cold…

> I own a Tesla which has some of the lowest impact.

I have a suspicioun those cars that seem to have no impact on range due to temperature just increase the deepth of discharge in colder weather.

I.e. Tesla and Jaguar.

Re: The cold hard truth about electric vehicles in winter

#23

Post by aetherspawn »

Tostino wrote: post #2

That is interesting to see the difference the manufacturers bake into their battery designs as far as software control goes. Tesla seems to quite tightly control pack charge and discharge through their bms, and limit things in software rather than hitting chemical limits of the batteries like some other manufacturers seem to be allowing.

Hitting the chemical limits of the batteries is what causes 1/ rapid aging and 2/ catastrophic cell damage and/or short failure and runaway, so if what you say is true (I don’t think it is) then the other manufacturers have implemented poor state of function control (SOF) and it would be a good idea to avoid.

Proper SOF control is loosely required for ECE R100 which most manufacturers would have, but OTOH I am convinced that it’s possible to fudge that certification.

Source: battery controls engineer.

Re: The cold hard truth about electric vehicles in winter

#24

Post by gambiting »

rcarr wrote: post #16

There's a long distance motorcycle travel series with Ewan McGregor and Charlie Boorman called "Long Way Up" where they go from the bottom of South America to LA on electric motorcycles. They had a lot issues with both range and charging the motorbikes in the first few episodes when they were dealing with the cold winter climate in Tierra del Fuego. Once they got far enough north into warmer climates the bikes were c…

The entire series of Long Way Up felt like it was filmed maybe ~5 years too early. So many of the issues were caused by the bikes just being prototypes.

Also the solution is easy - when the car is plugged in, just heat the battery so it charges at optimal rate and is ready for your journey. Some cars already do this(the new BMW i4 and I guess the iX too)

Re: The cold hard truth about electric vehicles in winter

#26

Post by api »

thrashh wrote: post #20
rcarr wrote: post #16

There's a long distance motorcycle travel series with Ewan McGregor and Charlie Boorman called "Long Way Up" where they go from the bottom of South America to LA on electric motorcycles. They had a lot issues with both range and charging the motorbikes in the first few episodes when they were dealing with the cold winter climate in Tierra del Fuego. Once they got far enough north into warmer climates the bikes were c…

Hopefully we discover a new battery chemistry We seem to stumble on new chemistries that get to production every few decades so cross your fingers

Or just more range. If you have 350 miles of range and it drops to 300 in the winter that’s not noticeable for 99% of drivers.

We have a 220 mile Nissan Leaf that drops to 180-200 in the winter. We also live in Cincinnati which is a metro area about 75 miles in diameter at the widest span. Most drives are 10-30 miles. The range drop doesn’t matter unless you are doing a road trip.

Recharge time does matter more but any drop there due to slower chemistry is somewhat offset by less thermal down-ramping since everything is cold.

What we need most of all is more fast chargers between cities. There are enough in California and several other coastal states but nowhere near enough between cities in the US interior.

For some reason they put a bunch of DC chargers in the city and none between which is the inverse of what you really need. Is there a grid capacity problem in small midwestern towns or did they just get the priority wrong?

Re: The cold hard truth about electric vehicles in winter

#27

Post by justahuman74 »

d_watt wrote: post #19

Anecdotally last winter, had a Model Y up in maine for a trip home. I arrived at a backwoods house with ~60 miles left. It was around 10 farenheit the next day when I hooked up a 110 volt line to the car. Over the next 30 minutes the mileage dropped to 55 as it took more energy to heat the battery than the line could deliver. I unhooked it and planned to drive 20 miles to the nearest charger, but after 1 mile of trav…

The 115v lines just arent enough, it may have been quite ok using a 240v though (from say a dryer plug)

Re: The cold hard truth about electric vehicles in winter

#28

Post by brianglick »

d_watt wrote: post #19

Anecdotally last winter, had a Model Y up in maine for a trip home. I arrived at a backwoods house with ~60 miles left. It was around 10 farenheit the next day when I hooked up a 110 volt line to the car. Over the next 30 minutes the mileage dropped to 55 as it took more energy to heat the battery than the line could deliver. I unhooked it and planned to drive 20 miles to the nearest charger, but after 1 mile of trav…

You wouldn't really need a heated garage (at home, anyway) if you had a 220 volt charger. That should be able to overcome any charging challenges in extreme cold, anyway. Relatively easy to get that into your garage.

Also - if you arrive at your friend's place in the winter and park overnight, you won't lose a ton overnight if the car's just parked there.

Re: The cold hard truth about electric vehicles in winter

#29

Post by jackmott »

d_watt wrote: post #19

Anecdotally last winter, had a Model Y up in maine for a trip home. I arrived at a backwoods house with ~60 miles left. It was around 10 farenheit the next day when I hooked up a 110 volt line to the car. Over the next 30 minutes the mileage dropped to 55 as it took more energy to heat the battery than the line could deliver. I unhooked it and planned to drive 20 miles to the nearest charger, but after 1 mile of trav…

You only need a 220volt plug, then its fine.

You can also leave it overnight just fine. I think plugging a 110v during the cold is kind of an edge case, the car tries to charge but it makes thing worse. Maybe a software update would cure that.

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