low-voltage battery & cold weather

[yurmix]

I hope you read the (somewhat biased) article from the NYTimes on the weather struggles people had this week with their Tesla.
(TL;DR: apparently people don't pay enough attention to how to operate their vehicle in extreme-cold conditions...)

In any case, they interviewed a former Tesla employee and a current EV advocate, Albert Gore III, which mentioned that a big issue with cold weather is that the 12-volt battery can lose charge:

Why does cold weather drain electric vehicle batteries?​

Unlike cars with internal combustion engines, an electric vehicle has two batteries: a low-voltage and a high-voltage. In particularly cold weather, the lower-voltage, 12-volt battery can also lose charge, like it does in traditional vehicles.
When that happens, the E.V. cannot charge at a fast charger until the low voltage battery has been jump-started, said Albert Gore III, a former Tesla employee who is now the executive director of the Zero Emission Transportation Association, which represents automakers including Tesla and has released a tips sheet for operating electric vehicles in cold weather.

My questions:
1. Do you think this is really the issue? (I mean, this guy isn't an engineer).
2. What does that mean for the 48v Li-ion in the Cybertruck?

 

[Supcom]

I hope you read the (somewhat biased) article from the NYTimes on the weather struggles people had this week with their Tesla.
(TL;DR: apparently people don't pay enough attention to how to operate their vehicle in extreme-cold conditions...)

In any case, they interviewed a former Tesla employee and a current EV advocate, Albert Gore III, which mentioned that a big issue with cold weather is that the 12-volt battery can lose charge:


My questions:
1. Do you think this is really the issue? (I mean, this guy isn't an engineer).
2. What does that mean for the 48v Li-ion in the Cybertruck?

The 12V battery in an older Tesla, like my M3, can certainly cause a failure. Like any lead acid battery, extreme cold or heat can trigger a battery failure. If that occurs, then the high voltage contactors for the main battery cannot be activated and the car sits dead. Healthy batteries do not just 'lose charge' unless the car sits for a very long time (months?). The problem comes when the battery is nearing the end of its useful life. ICE cars have the same issues with starter batteries.

Newer Teslas, including cyber truck, use a lithium ion low voltage battery that should be more reliable than the lead acid batteries.

 

[yurmix]

The 12V battery in an older Tesla, like my M3, can certainly cause a failure. Like any lead acid battery, extreme cold or heat can trigger a battery failure. If that occurs, then the high voltage contactors for the main battery cannot be activated and the car sits dead. Healthy batteries do not just 'lose charge' unless the car sits for a very long time (months?). The problem comes when the battery is nearing the end of its useful life. ICE cars have the same issues with starter batteries.

Newer Teslas, including cyber truck, use a lithium ion low voltage battery that should be more reliable than the lead acid batteries.

Interesting, I never realized newer vehicles with v12 already have a Li-ion battery. Mine (Match 2021 MY) is just a few months older than the cutoff. Luckily I live in warm climate

 

[MY1stEV]

The story around the incident in Chicago was heavy on FUD and short on FAQs.

I dont think the issue these people were facing was related to the 12v battery. If the 12v battery was zapped by the cold, they wouldn't have been able to get into their cars in the first place.

I didn't see anyone say that the supercharger was offline and that is why these cars wouldn't charge, so my suspicion is that the majority of these people either live in apartments or in homes with street parking and no access to at home charging. They headed out with their HV batteries already at a low state of charge, very cold, and drove straight to the closest supercharger without preconditioning the battery.

The batteries in an EV wont charge if they are too cold. When you plug into the supercharger with a stone cold battery, the first thing the supercharger is going to do is supply a small amount of power for the car to use just to warm the battery. (It runs the motors disengaged from the wheels and dumps the waste heat into the battery.)

On the Out of Spec Review YouTube channel, they did a test with a Tesla that sat outside all night in similar temperatures. It took 45 minutes plugged into the supercharger -- just warming the HV battery -- before the car even began to charge.

Someone online also said that these cars appeared to be older Teslas, which would have resistive heating and not a heat pump. I don't know if that is true or not, but if true, then the people waiting to charge were probably further depleting their batteries and not doing anything to warm the HV battery up.

And please don't get the impression I am blaming or shaming the people this happened to. It was a terribly aggravating situation on an already miserably cold day.