Cold weather - where'd the power go??

[Carsinmyblood]

Overnight we had a cold snap. My GOM showed that I lost about 20 miles in range and a corresponding drop in %.

So, where'd it go? Is that energy still in the battery? If the temperature climbs back to normal does the battery find it and make it available again? Is it a change in the battery's chemistry?

What's the science behind the cold weather loss?

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[DevSecOps]

Overnight we had a cold snap. My GOM showed that I lost about 20 miles in range and a corresponding drop in %.

So, where'd it go? Is that energy still in the battery? If the temperature climbs back to normal does the battery find it and make it available again? Is it a change in the battery's chemistry?

What's the science behind the cold weather loss?

Since I'm not a batteryologist I'll defer your to a good article on it. It's not gone forever it will return with the warmer weather.

https://www.recurrentauto.com/research/how-temperature-affects-ev-range

 

[Carsinmyblood]

Since I'm not a batteryologist I'll defer your to a good article on it. It's not gone forever it will return with the warmer weather.

https://www.recurrentauto.com/research/how-temperature-affects-ev-range

Yea, I know range capacity isn't deleted forever. I'm really wondering how the battery sheds the energy pumped into it. You could put a fully charged car in a garage and leave it until it's gone dead. Normally, it's called vampire loss in an older car. (clock, old wiring, failing insulation, etc.)

In an EV, it's something else. .....What?

 

[DevSecOps]

Yea, I know range capacity isn't deleted forever. I'm really wondering how the battery sheds the energy pumped into it. You could put a fully charged car in a garage and leave it until it's gone dead. Normally, it's called vampire loss in an older car. (clock, old wiring, failing insulation, etc.)

In an EV, it's something else. .....What?

I'll pull in @Mach-Lee. His battery wisdom is quite amazing.

 

[BMT1071]

Overnight we had a cold snap. My GOM showed that I lost about 20 miles in range and a corresponding drop in %.

So, where'd it go? Is that energy still in the battery? If the temperature climbs back to normal does the battery find it and make it available again? Is it a change in the battery's chemistry?

What's the science behind the cold weather loss?

The GOM change makes sense. The change in % does not. ?

 

[Mach-Lee]

Overnight we had a cold snap. My GOM showed that I lost about 20 miles in range and a corresponding drop in %.

So, where'd it go? Is that energy still in the battery? If the temperature climbs back to normal does the battery find it and make it available again? Is it a change in the battery's chemistry?

What's the science behind the cold weather loss?

I'm not an expert on the GOM algorithm (still somewhat of an enigma), but can speak about the science.

Energy from the battery comes from a chemical reaction, the rate of which is governed by demand and also temperature. You may remember from chemistry class that the rate of chemical reactions is proportional to temperature (rate approximately doubles for every 10ºC increase in temp). This means in cold temps the reaction slows down, and this effectively shrinks the size of the battery (you'd need a larger battery to get the same current with the same voltage drop as before). The same amount of charge is still stored in the battery as before (same mass, etc), but because it's "harder" to extract the electrons from the battery when cold, the range will go down due to higher voltage drop. This is temporary however. As soon as the battery warms up this range will become accessible again because it was never lost, it was just more difficult to use in the cold. The car should hopefully heat up the battery to an acceptable temperature after you've been driving 10-15 minutes which would restore the lost range.

However the GOM may also be figuring your climate control usage as well, in cold temps a loss of 20 miles due to that energy being used for heat instead of traction seems reasonable. I wonder if it remembers your setpoint or if it uses a set value for the climate range model?

The % drop is probably not much to worry about, the cell voltage will slip slightly in cold temps so that might be having an effect. Displayed SoC is just an estimate anyway subject to some error.

Charging in freezing temps is a different story however, if cold cells are charged too fast the anode can get lithium plated which will permanently reduce the capacity. This is because the normal chemical reaction can't keep up with the elections being pushed through the cells, and this undesirable side reaction develops. This is only a problem when an external force is driving the reaction (a charger). The battery self-regulates during discharge, so driving it cold won't cause damage, it will just be slower. The obvious solution is to warm up the battery before charging, this is indeed what it will do.

So just like you, the battery doesn't like to be too hot or cold to work optimally. In the winter, a warm battery is a happy battery. That's why using remote start, plugging in, and parking in a closed or heated garage helps keep things warm. But if you can't, you'll just have to wait longer for things to warm up and get back to normal.

 

[Gimme_my_MME]

I'm not an expert on the GOM algorithm (still somewhat of an enigma), but can speak about the science.

Energy from the battery comes from a chemical reaction, the rate of which is governed by demand and also temperature. You may remember from chemistry class that the rate of chemical reactions is proportional to temperature (rate approximately doubles for every 10ºC increase in temp). This means in cold temps the reaction slows down, and this effectively shrinks the size of the battery (you'd need a larger battery to get the same current with the same voltage drop as before). The same amount of charge is still stored in the battery as before (same mass, etc), but because it's "harder" to extract the electrons from the battery when cold, the range will go down due to higher voltage drop. This is temporary however. As soon as the battery warms up this range will become accessible again because it was never lost, it was just more difficult to use in the cold. The car should hopefully heat up the battery to an acceptable temperature after you've been driving 10-15 minutes which would restore the lost range.

However the GOM may also be figuring your climate control usage as well, in cold temps a loss of 20 miles due to that energy being used for heat instead of traction seems reasonable. I wonder if it remembers your setpoint or if it uses a set value for the climate range model?

The % drop is probably not much to worry about, the cell voltage will slip slightly in cold temps so that might be having an effect. Displayed SoC is just an estimate anyway subject to some error.

Charging in freezing temps is a different story however, if cold cells are charged too fast the anode can get lithium plated which will permanently reduce the capacity. This is because the normal chemical reaction can't keep up with the elections being pushed through the cells, and this undesirable side reaction develops. This is only a problem when an external force is driving the reaction (a charger). The battery self-regulates during discharge, so driving it cold won't cause damage, it will just be slower. The obvious solution is to warm up the battery before charging, this is indeed what it will do.

So just like you, the battery doesn't like to be too hot or cold to work optimally. In the winter, a warm battery is a happy battery. That's why using remote start, plugging in, and parking in a closed or heated garage helps keep things warm. But if you can't, you'll just have to wait longer for things to warm up and get back to normal.

 

[SeaKayaker4Life]

If you have a Departure Time set and aren’t plugged in it will use battery to pre-condition the cockpit and maybe warm the battery itself. Not sure if that’s the case here.

 

[Kevin P]

The battery doesn't shed much energy, the energy usage goes up when the temperature goes down. The extra usage for heating the battery itself, and the car, is why the range drops, as I understand it.

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