Model 3 Battery Heating?

[diamond.g]

And how do you know the battery is getting colder as it's supercharging?

Model S has a dedicated heater for the battery doesn't it. The Model 3 does not have that.

It would be cool for Tesla to show you how much power is being used to bring your battery up to temp versus charging. Though based on my last post Bjorn makes it appear as though aggressive throttle will warm the battery up faster than even supercharging.

 

[David99]

Why 0 degrees C? 0C only has significance to water as far as I know and I don't believe battery cells contain any water. Is 0C just a convenient number to apply to lithium ion charging?

I trust Tesla knowing a thing about their batteries. I'm not a chemist knowing what is exactly going on inside a cell but I think Tesla has a few of them

 

[David99]

It would be cool for Tesla to show you how much power is being used to bring your battery up to temp versus charging. Though based on my last post Bjorn makes it appear as though aggressive throttle will warm the battery up faster than even supercharging.

I did some tests with my Model S here: Energy consumption for Preheating

Since the Model 3 has a similar sized battery the energy to heat the battery up should be similar.

As for Supercharging with a cold battery, I think Bjorn tried to show that driving the car hard for a few minutes will warm up the battery enough to gt a faster charge rate at the supercharger. When plugging in cold, the charge rate would be slower and you would spend more time. The faster charge speed would more than make up for the few minutes of driving. I don't know if I like the idea to push a cold battery with hard acceleration.

 

[navinsiri]

And how do you know the battery is getting colder as it's supercharging?

Model S has a dedicated heater for the battery doesn't it. The Model 3 does not have that.

I can’t know for sure that the battery is getting cold but the supercharger speed continually drops much faster than it should. Typically it can pull almost 120kW all the way to 50%. But yesterday I plugged in at 30% and it only charged at 65kW and dropped slowly to 38kW before 50% and stayed there until I unplugged.

If the Model 3 was heating the battery (even through the motor/inverter) it should show up on the energy meter while stationary like it does on the S/X. However, when I turn off the cabin heater the meter drops to 0. Unlike the S which would still show power consumption for the battery heater.

 

[Big Earl]

I can’t know for sure that the battery is getting cold but the supercharger speed continually drops much faster than it should. Typically it can pull almost 120kW all the way to 50%. But yesterday I plugged in at 30% and it only charged at 65kW and dropped slowly to 38kW before 50% and stayed there until I unplugged.

If the Model 3 was heating the battery (even through the motor/inverter) it should show up on the energy meter while stationary like it does on the S/X. However, when I turn off the cabin heater the meter drops to 0. Unlike the S which would still show power consumption for the battery heater.

Same happened to my husband last night. He plugged in at 50%, it started out at 35 kW, dropped to 26 kW by 60% and back up to 28 kW by the time he unplugged at 75%.

This issue really becomes a problem for locals who don't have home charging and also don't regularly drive long distances to warm up the battery. These folks will be spending a lot of time at Superchargers in the cold. This additional time spent charging also clogs up the Superchargers.

I suspect future software updates will have more aggressive battery heating. S & X had various updates over the years that changed the target heating temperature by several degrees. I think an elegant solution would be to add a button to the app's climate tab allowing you to condition the battery for charging. This would allow you to precondition the battery when needed, but not waste an excessive amount of energy when it isn't necessary.

 

[derotam]

So just curious and both Big Earl and navinssiri, was the car fully warm when first plugged into the supercharger? Did you have full regen capability..or was the car cold because it hadn't been driven much before plugging in?

 

[Nocturnal]

I did some tests with my Model S here: Energy consumption for Preheating

Since the Model 3 has a similar sized battery the energy to heat the battery up should be similar.

As for Supercharging with a cold battery, I think Bjorn tried to show that driving the car hard for a few minutes will warm up the battery enough to gt a faster charge rate at the supercharger. When plugging in cold, the charge rate would be slower and you would spend more time. The faster charge speed would more than make up for the few minutes of driving. I don't know if I like the idea to push a cold battery with hard acceleration.

Yes, I'm struggling to see the situation where you would be at a supercharger with a cold battery. FWIW I charged on a road trip last week in 15 degree weather with an SOC of under 5% with no issues.

This issue really becomes a problem for locals who don't have home charging and also don't regularly drive long distances to warm up the battery. These folks will be spending a lot of time at Superchargers in the cold. This additional time spent charging also clogs up the Superchargers.

I don't understand anyone that would plan on this method of keeping their car charged. Not good for the battery, but more an issue of wasted time. Spend 20 minutes every other day to sit there while charging? Pass.

 

[navinsiri]

So just curious and both Big Earl and navinssiri, was the car fully warm when first plugged into the supercharger? Did you have full regen capability..or was the car cold because it hadn't been driven much before plugging in?

I had been driving for 1.5 hours before I plugged in and there was no limit on regen. But I was stuck in a lot of traffic so it might not have been fully warmed to the point where it can accept the max charge rate. But still having the charge rate slow down as you’re charging (with SOC <50%) shouldn’t be normal

 

[Big Earl]

So just curious and both Big Earl and navinssiri, was the car fully warm when first plugged into the supercharger? Did you have full regen capability..or was the car cold because it hadn't been driven much before plugging in?

Sorry, I should have clarified. He's been making short trips all week, so the car was not warm. Temperatures below 50F.

 

[Big Earl]

Yes, I'm struggling to see the situation where you would be at a supercharger with a cold battery. FWIW I charged on a road trip last week in 15 degree weather with an SOC of under 5% with no issues.


I don't understand anyone that would plan on this method of keeping their car charged. Not good for the battery, but more an issue of wasted time. Spend 20 minutes every other day to sit there while charging? Pass.

Plenty of people who live in condominiums, town houses and apartments with off-street parking are buying Model 3s. I'm not one of them, but there are a few in our local EV group. There are also the cases of being out of town on a business trip, visiting family or going on a vacation to places without level 2 charging.

 

[derotam]

Yeah a cold or cool battery definitely could cause reduced charge rate. Not saying this was exactly the cause but it could be at least part of what happened. That much reduction does seem excessive, but depending on outside temp in that stop and go traffic, who knows.

 

[Rocky_H]

These descriptions about it being cold in the mornings could have made sense as far as a slow charging rate to start with. But this behavior of it starting off semi-slow, and getting slower as it progresses doesn't make any sense. Standard S/X behavior would be that it always continues to increase the charging rate as the charging and battery heating warm it up, and the 3 should be pretty similar.

 

[Nocturnal]

Plenty of people who live in condominiums, town houses and apartments with off-street parking are buying Model 3s. I'm not one of them, but there are a few in our local EV group. There are also the cases of being out of town on a business trip, visiting family or going on a vacation to places without level 2 charging.

It's hard for me to understand somebody going through this much extra effort and wasted time relying on SCs.

 

[Rocky_H]

It's hard for me to understand somebody going through this much extra effort and wasted time relying on SCs.

As opposed to driving a gas car? Some people would like to switch to an electric car but live in a place where they can't install an overnight charging connection. You think they're inconveniencing themselves on purpose to be masochists?

 

[Jeff N]

There is some general background on the cold charging issue in this article I wrote recently although it is not written specifically about the Model 3:

https://electricrevs.com/2018/10/23/frigidity-and-the-challenge-of-high-power-coupling/

 

[Nocturnal]

As opposed to driving a gas car? Some people would like to switch to an electric car but live in a place where they can't install an overnight charging connection. You think they're inconveniencing themselves on purpose to be masochists?

I think it's a poor choice and also places extra burden on the SC network for travelers. To each his own though.

 

[Rocky_H]

I think it's a poor choice and also places extra burden on the SC network for travelers. To each his own though.

THIS again? It's 2018. "the SC network for travelers" hasn't been a thing for the past couple of years. Tesla has been very clear for quite a while that Superchargers are also for apartment dwellers' regular and only charging solution if they wish.

 

[Big Earl]

I think it's a poor choice and also places extra burden on the SC network for travelers. To each his own though.

That's the whole purpose of urban Superchargers.

 

[Big Earl]

Same happened to my husband last night. He plugged in at 50%, it started out at 35 kW, dropped to 26 kW by 60% and back up to 28 kW by the time he unplugged at 75%.

This issue really becomes a problem for locals who don't have home charging and also don't regularly drive long distances to warm up the battery. These folks will be spending a lot of time at Superchargers in the cold. This additional time spent charging also clogs up the Superchargers.

I suspect future software updates will have more aggressive battery heating. S & X had various updates over the years that changed the target heating temperature by several degrees. I think an elegant solution would be to add a button to the app's climate tab allowing you to condition the battery for charging. This would allow you to precondition the battery when needed, but not waste an excessive amount of energy when it isn't necessary.

It might be helpful for people to like or retweet my tweet about battery conditioning for charging.

 

[Nocturnal]

THIS again? It's 2018. "the SC network for travelers" hasn't been a thing for the past couple of years. Tesla has been very clear for quite a while that Superchargers are also for apartment dwellers' regular and only charging solution if they wish.

Still stupid. And all the people complaining about busy SC locations likely agree.