Yep. We'll see in just a few days. It's supposed to drop below freezing overnight this weekend, so hopefully we'll have an answer one way or the other.
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Model 3 Battery Heating?
- Thread starter ratsbew
- Start date
Yep. We'll see in just a few days. It's supposed to drop below freezing overnight this weekend, so hopefully we'll have an answer one way or the other.
Jaguar
Member
It helps to read the Model 3 manual, which says:
"Note: In cold weather, some of the stored energy in the Battery may not be available until the Battery warms up. When this happens, a portion of the Battery meter is blue and the driving distance value has a snowflake image next to it. If Model 3 is plugged in, you can heat your Battery using wall power by turning on climate control using the mobile app. When the Battery warms up, the blue portion on the meter and the snowflake image are no longer displayed."
"Note: In cold weather, some of the stored energy in the Battery may not be available until the Battery warms up. When this happens, a portion of the Battery meter is blue and the driving distance value has a snowflake image next to it. If Model 3 is plugged in, you can heat your Battery using wall power by turning on climate control using the mobile app. When the Battery warms up, the blue portion on the meter and the snowflake image are no longer displayed."
Based on other documentation as to the battery cooling/heating mechanism, the statement in the manual may be a mistake/misworded as far as the technical reason the battery is warming up. Turning on Climate control may also turn on the battery warming system but those are two different systems. Cabin heat is from a resistive heating core that the battery's glycol system doesn't interface with, at least not from all the documentation that is out there. People are reading that statement in the manual and assuming it means that the cabin heat is warming the battery but it doesn't specifically state that.
Jaguar
Member
I assumed the battery heating was triggered by the request to condition the cabin, not that the cabin conditioning heated the battery. Two different mechanisms, same trigger.
But a lot of people are mis-reading it. A lot of people also think that turning on the climate control will always warm the battery, with the goal of having full regeneration capability when they start driving. The battery warming trigger is a lower temperature trigger than the regeneration limitation temperature trigger.
I don't think people are assuming that the cabin heater is heating the battery. Most of us understand that there are two separate systems that are - according to the manual - both activated during remote pre-conditioning.
Correct. Battery heating target temperature is only like 50F, which is just enough to get *some* regen back as well as free up unavailable battery power (indicated by the blue snowflake) due to cold temperature. If the battery isn't below this temperature, pre-conditioning will not activate battery heating. The target temperatures may have changed with the Model 3 ... we won't know until later on in the cold weather season.
How does the battery-heating behave when preheating, driving etc? In my Model S with range mode off batteryheater uses 3-6kW until I have about 30kW-regen and no effect limit. With range mode on battery is only heated when temp is like -5C or lower. All other heating is passive and happends during driving. How does this work on Model 3 when motor is used for heating instead for dedicated heater like in S and X? How much regen is available after preheating? Does car consume extra energy for a while when driving until battery-temp is reached?
It's too early to tell, as North America hasn't really dipped into the single digit temperatures yet.
However, I can provide some information based on what I and others have read.
- Model 3 can use the motor and drive inverter to provide up to 4 kW worth of heat for the battery.
- The heating output is variable, unlike the Model S & X.
- Range mode on S & X appears to stop battery heating entirely, according to Bjorn's -36C overnight test in his X.
- Model 3 does not have a range mode option.
- I hear, but have no way of confirming, that the active heating target temperature on the Model 3 has been lowered from what it was on the S & X (10C).
It can if the computer deems battery heating to be necessary. What influences the computer's decisions has yet to be determined.
Dan Detweiler
Active Member
Thx for reply. 4kW seems like a descent amount. S and X has larger batteries total volume so 4 instead of 6kW max seems fair. In my Model S it seems batteryheater draws 6kW in very low temps, below 0C, when outside temp is around 5C and I have about 10-15kW regen it draws 3kW with range mode OFF. I have tested several times 2 years ago that battery-heater started when outside-temp was -15C and car had been parked without preheat for several hours in range mode. The power draw was 3kW and lasted untill I had about 3kW-regen. I didnt test this last winter so I dont know if firmware-updates has changed this. It could also be different between S and X but I can confirm that range mode previously has started heater when battery was like -10 to -5C in my Model S. I had climate turned off so that would not be a source off error. One thing I noticed is that when temp is that low, batteryheater doesnt start right away, but after driving about 3 minutes it starts. Maybe to save energy on very short trips?
I have seen som canbus-reads from Model S owners who claim that temp target on battery has been changed several times. Some claim it has been 8C and also 12C in other firmwares.
Nowadays I keep range mode off when car is parked, preheat some and turn it on when I drive. Far less consumption on short trips, and I usually get around 15kW-regen which makes me rarely use the brakepedal.
One thing I don`t fully understand is why Tesla completely disables regen when temp is below 0C. According to battery university and several reports I have read, you can charge the battery when below 0C, but you have to do it very slowly. At around 5% of 1C (5kW-regen\chargespeed on a 100kW-battery) it does not cause damage to cells even at -15C. We have Nissan Leaf and Kia Soul as company-cars and even if they have been unplugged in -10C for several days and with no preheating you still have a bit off regen instantly (so no batteryheating can have occured) while driving (about 5kW in Leaf, Soul just shows 1 of 4 bars). Is Tesla just extra careful or does the chemistry in Soul\Leaf allow slow charge\light regen in sub-zero temps?
Kermee
It's Not Easy Being Green
There's no hard confirmed answers, but my guess is it's a combination of both.
1. Chemistry and mixture of NCA in the cells.
2. Buffer and bring extra careful.
Lithium plating due to charging a battery under a certain temperature causes permanent, and potentially catastrophic damage.
I think Tesla would rather disable regen until the temperature of the battery is sufficiently warm enough. For myself, and my sanity, I just put blind faith into Tesla's engineers for the BMS system and accept it for what it is at the moment. A few seconds of charging into a battery that's too cold will instantly cause permanent damage. Safer than sorry.
1. Chemistry and mixture of NCA in the cells.
2. Buffer and bring extra careful.
Lithium plating due to charging a battery under a certain temperature causes permanent, and potentially catastrophic damage.
I think Tesla would rather disable regen until the temperature of the battery is sufficiently warm enough. For myself, and my sanity, I just put blind faith into Tesla's engineers for the BMS system and accept it for what it is at the moment. A few seconds of charging into a battery that's too cold will instantly cause permanent damage. Safer than sorry.
But the evidence from several lithium-battery-chemistries suggest that there is no permanent damage to the battery as long as the charging is slow. But something might be different with NCA as you suggest. Tesla is very careful when battery is below 15C and begins reducing regen. One of the oldest Leafs still ha lost no bars after 7 years and has okay regen. I hope Tesla will improve charging\regen in cold weather for the packs in the future since the competition has a clear advantage now.
I leave my M3 plugged into 240v dryer socket in garage. With climate control off, outside temp 20F, garage temp 50F, house temp 70F, I woke up one morning to cabin temp of 85F. I turned on climate control to LO to cool cabin to 75F and then turned Climate off and unplugged and cabin eventually cooled even more. The car sits in garage several days between usage. Should I not be leaving it plugged in all the time? I keep the battery charged to 183 miles on a 310 battery.