Battery Thermal Management

[gpsman]

I drove 230 miles at 65 mph at 41’F ( 5’C ).

 

[Anonymous]

Can we forced a battery conditioning before recharging on a fast charger in cold weather to make sure that it will recharge at a rate faster than 17Kwh? especially at -17 Celsius?

 

[gpsman]

This was just discussed in another thread.
Basically, yes.

On your way to the DCFC do a few full throttle accelerations followed by a few heavy regen pulses (IE use the paddle in “L”). Do this six to ten times.

The high current will warm the battery from the inside. The battery heating element is less than 1 kw. It is meant to heat your battery while plugged in overnight for 12 hours.

Pull 160 kw out of the battery at 90% efficiency and you are putting 16 kw of heat into the battery. Regen at 60 kw and you are putting 6 kw of heat into the battery.

 

[GetOffYourGas]

Sure, but you also just used that much more of your battery, which now needs to be replenished. I haven't done the math, but I don't feel like it works out in your favor. I doubt you really save any time in the end by doing this.

 

[SparkE]

I think it's more about saving money (if you are paying $15 for 30 mins of charging, it's much better if the first 10 mins are at 50 kW instead of 17 kW).

 

[gpsman]

A guy in Canada with a Tesla cold soaked at -17C was getting 2kw out of a Supercharger.

He “drove it like he sole it” for 4.5 miles over 10 minutes. This warmed the battery.

Came back to the same SuperCharger and the car started charging at 64 kw.

So ya, it works in your favor. More so the colder it is outside.

Funny side note: at -17C it took 2 hands to bend the Supercharger cable to connect to the car. It was very stiff (rigid) at that temperature.

 

[SparkE]

Funny side note: at -17C it took 2 hands to bend the Supercharger cable to connect to the car. It was very stiff (rigid) at that temperature.

For you Fahrenheiters, it's not as cold as you might initially think. -17C is about 1F (still cold, but not -17F cold).

 

[GetOffYourGas]

I think it's more about saving money (if you are paying $15 for 30 mins of charging, it's much better if the first 10 mins are at 50 kW instead of 17 kW).

Same difference. If you use more electricity in order to charge faster, and then get more back, you're "saving money" in the same way that buying that extra item because it's 50% off (and not because you need it anyway) saves you money.

A guy in Canada with a Tesla cold soaked at -17C was getting 2kw out of a Supercharger.

He “drove it like he sole it” for 4.5 miles over 10 minutes. This warmed the battery.

Came back to the same Supercharger and the car started charging at 64 kw.

So ya, it works in your favor. More so the colder it is outside.

Funny side note: at -17C it took 2 hands to bend the Supercharger cable to connect to the car. It was very stiff (rigid) at that temperature.

Now that's an interesting data point. So it's certainly possible that it works out in your favor. However, these is apples-to-oranges. Tesla not only has a different chemistry for their battery (and 2x more powerful motors to really crank up the draw), but they also have different software algorithms deciding how much power to draw. Tesla is definitely more willing to push the limits than GM. GM is ultra-conservative by comparison. This experience may or may not map to the Bolt.

An interesting experiment, though. If someone here lives in a cold climate and has access to a DCQC without connection fees (e.g. a free charger nearby or EVGo's On-The-Go plan), you could replicate the above conditions and determine whether the Bolt acts in the same way.

 

[SparkE]

I think it's more about saving money (if you are paying $15 for 30 mins of charging, it's much better if the first 10 mins are at 50 kW instead of 17 kW).

Same difference. If you use more electricity in order to charge faster, and then get more back, you're "saving money" in the same way that buying that extra item because it's 50% off (and not because you need it anyway) saves you money.

A guy in Canada with a Tesla cold soaked at -17C was getting 2kw out of a Supercharger.

He “drove it like he sole it” for 4.5 miles over 10 minutes. This warmed the battery.

Came back to the same Supercharger and the car started charging at 64 kw.

So ya, it works in your favor. More so the colder it is outside.

Funny side note: at -17C it took 2 hands to bend the Supercharger cable to connect to the car. It was very stiff (rigid) at that temperature.

Now that's an interesting data point. So it's certainly possible that it works out in your favor. However, these is apples-to-oranges. Tesla not only has a different chemistry for their battery (and 2x more powerful motors to really crank up the draw), but they also have different software algorithms deciding how much power to draw. Tesla is definitely more willing to push the limits than GM. GM is ultra-conservative by comparison. This experience may or may not map to the Bolt.

An interesting experiment, though. If someone here lives in a cold climate and has access to a DCQC without connection fees (e.g. a free charger nearby or EVGo's On-The-Go plan), you could replicate the above conditions and determine whether the Bolt acts in the same way.

Sort of my point (story from gpsman). IF you "waste" 2 kWh speeding up and slowing down to warm the battery so that you are able to get 23 kWh in 30 mins instead of 14 kWh in the same time, it's a win. Especially if you can make it safely home after a single 30 min charge after "wasting" 2 kWh to heat your battery; instead of sitting through a 2nd charge session of 30 minutes you have saved not only money, but 30 minutes of your time. Double especially if your wife is in the passenger seat in 10F weather glaring daggers at you while you wait for the car to charge enough for you to leave for home. :mrgreen:

This should only make much a charging speed/rate difference if it were really cold (<-6C/25F).

I also would like to hear stories involving Bolts. (Although the person would prob waste less MONEY if they were using a charge station with no connection fee for the testing.)

 

[bro19991]

I think it's more about saving money (if you are paying $15 for 30 mins of charging, it's much better if the first 10 mins are at 50 kW instead of 17 kW).

Same difference. If you use more electricity in order to charge faster, and then get more back, you're "saving money" in the same way that buying that extra item because it's 50% off (and not because you need it anyway) saves you money.

A guy in Canada with a Tesla cold soaked at -17C was getting 2kw out of a Supercharger.

He “drove it like he sole it” for 4.5 miles over 10 minutes. This warmed the battery.

Came back to the same Supercharger and the car started charging at 64 kw.

So ya, it works in your favor. More so the colder it is outside.

Funny side note: at -17C it took 2 hands to bend the Supercharger cable to connect to the car. It was very stiff (rigid) at that temperature.

Now that's an interesting data point. So it's certainly possible that it works out in your favor. However, these is apples-to-oranges. Tesla not only has a different chemistry for their battery (and 2x more powerful motors to really crank up the draw), but they also have different software algorithms deciding how much power to draw. Tesla is definitely more willing to push the limits than GM. GM is ultra-conservative by comparison. This experience may or may not map to the Bolt.

An interesting experiment, though. If someone here lives in a cold climate and has access to a DCQC without connection fees (e.g. a free charger nearby or EVGo's On-The-Go plan), you could replicate the above conditions and determine whether the Bolt acts in the same way.

Sort of my point (story from gpsman). IF you "waste" 2 kWh speeding up and slowing down to warm the battery so that you are able to get 23 kWh in 30 mins instead of 14 kWh in the same time, it's a win. Especially if you can make it safely home after a single 30 min charge after "wasting" 2 kWh to heat your battery; instead of sitting through a 2nd charge session of 30 minutes you have saved not only money, but 30 minutes of your time. Double especially if your wife is in the passenger seat in 10F weather glaring daggers at you while you wait for the car to charge enough for you to leave for home. :mrgreen:

This should only make much a charging speed/rate difference if it were really cold (<-6C/25F).

I also would like to hear stories involving Bolts. (Although the person would prob waste less MONEY if they were using a charge station with no connection fee for the testing.)

Pretty much was this trip of mine (staring daggers part).
https://bro05.blogspot.com/2017/12/this-is-not-going-to-go-way-you-think.html?m=1