Lack of battery heater may cause very slow SuC charging speed

[outdoors]

Without know the actual battery pack temperature this is all very speculative and guesswork. Ambient temperature doesn't say too much about battery temperature.

So how would one suggest getting these temps? My dogs cower in the corner when the vet comes in the room. They know what's up. Like you want me to go take its temperature? Wouldn't sitting in the cold for multiple days make the car come to some temperature where they would both be able show one car has a battery heater one does not. Or to see which one does what. Then maybe at battery consumption level. One would lose more than the other.

Is there another way? I mean really. I am willing to get a FLIR cam so we can see what's going on.

 

[David99]

So how would one suggest getting these temps? My dogs cower in the corner when the vet comes in the room. They know what's up. Like you want me to go take its temperature? Wouldn't sitting in the cold for multiple days make the car come to some temperature where they would both be able show one car has a battery heater one does not. Or to see which one does what. Then maybe at battery consumption level. One would lose more than the other.

Is there another way? I mean really. I am willing to get a FLIR cam so we can see what's going on.

Looking at the CAN bus data where you can read the temperature inside the battery. Unfortunately I don't know anyone who has hooked up a M3 to data logger, yet. It'll happen soon. I've been looking at the battery temperature vs ambient temperature on my Model S for alomost 2 years and from this experience it's just impossible to use outside temp as a gauge for battery temperature. So as of now it's just guesswork.

 

[mongo]

Couple words of advice for anyone new to FLIR: FLIR relies on emmisivity so bare aluminum will read differently than black anodized. Pieces of tape placed on the metal help with accurate readings (or verify the setting on the camera for the material type you are measuring)

Ideally, the exterior pack temperature will not be the same as the cell temps so external measurement will have questionable quantitative value, but qualitatively would show differences in heat leakage and potentially heater cycling (possibly time lagged).

 

[brkaus]

Could the interior temp be explained by better power management of the computers inside the car? I believe there have been some thermal imaging cameras showing significant heat coming from the dash of the S when parked.

 

[mongo]

Could the interior temp be explained by better power management of the computers inside the car? I believe there have been some thermal imaging cameras showing significant heat coming from the dash of the S when parked.

Good point, the 3 pack integrates a lot of the stuff that would put waste heat in the cabin. HVJB, charger, 12V converter. One less display (some TFTs have built in heaters). With the new setup, there should be less heat/ loss when charging the 12V battery.

 

[scaesare]

Good point, the 3 pack integrates a lot of the stuff that would put waste heat in the cabin. HVJB, charger, 12V converter. One less display (some TFTs have built in heaters). With the new setup, there should be less heat/ loss when charging the 12V battery.

Your point is well taken (lots o' stuff in the cabin), but the 12V DC-DC converter is outside the cabin, no? In my early S it's behind the passenger side wheel well. In newer models I believed it got moved when they also moved the 12V battery, but I thought it was still outside the cabin in the frunk area...

 

[mongo]

Your point is well taken (lots o' stuff in the cabin), but the 12V DC-DC converter is outside the cabin, no? In my early S it's behind the passenger side wheel well. In newer models I believed it got moved when they also moved the 12V battery, but I thought it was still outside the cabin in the frunk area...

May very well be, that would make sense with the 12V battery location.

 

[worldburger]

Looking at the CAN bus data where you can read the temperature inside the battery. Unfortunately I don't know anyone who has hooked up a M3 to data logger, yet. It'll happen soon. I've been looking at the battery temperature vs ambient temperature on my Model S for alomost 2 years and from this experience it's just impossible to use outside temp as a gauge for battery temperature. So as of now it's just guesswork.

@David99 Where would you go to inform yourself how to log CAN data from an S or X?

 

[mspohr]

Looks like ~40 mins to get the battery up to temp for full charging.

I don't know that I've ever started a charge with my car that cold, although I've driven it at those temps.

How long would it take a Model S that's been cold-soaked to ~16 degrees to do the same?

My S can take 45 minutes to heat up to Max charge rate when it's cold.

 

[rhyd]

It is a physical feature of Lithium batteries that plating can occur if charged at very low temperatures so Tesla are just being responsible. It just means that you have to allow a little extra time if charging a cold car. I think it is a sensible move forward to lose the weight and extra parts complexity of a dedicated battery heater. The model S will delay charging to heat the battery first, but the dedicated heather just works a little quicker. Telsa Bjorn has shown that if you are in a rush, it is best to drive a cold-soaked car 60miles before charging. If not in a rush then just charge the car overnight and let the BMS do its thing.

In the Renault Zoe they use the motor as a transformer for 43KW AC charging, maybe that is next for the model Y; to have the motor act as motor/generator/heater/transformer

 

[johnanniegibson]

Good Morning, when we ordered our S in 2012 and took delivery in 2013, the manual, service center, and Elon advised us, it is good practice, to keep our cars plugged in when they are not in use; specifically during cold weather, and/or not going to be driven for an extended period of time (vacation, work traveling,etc). it was relayed to us by keeping your car (battery) plugged connected to even 110V, attributed to battery "health" during the cold and additionally cell balancing. there are many existing threads for this topic and Elon's statement came during a Q and A session.

When we received our X, we were instructed the same by the service center as our S would be spending more time idle than before.

I am unfamiliar with the Model 3 car/battery characteristics; however, i would humbly suggest, since you have "cold" battery data, attempt the same scenario with the car plugged in. The results will indeed help all of us Tesla family members.

have a good day drive safe

 

[Bill25cycle]

Normally, a motor is converting electrical energy to mechanical as efficiently as possible, so it doesn't heat up much. Torque is usually related to current, current causes heating in the motor windings due to resistance, P=I^2*R. So the motor is built so that the heat generated during operation can be removed such that the max temp of the windings/ bearings is not exceeded. This is the limit to how much heat you can reliably get from the motor.
To generate heat instead of motion, the inverter sends a stationary field instead of a rotating one (or if the car is moving, both an additional acceleration and deceleration field). But since the motor is not spinning, there is no back-EMF voltage to counteract the inverter drive, so the inverter needs to be able to throttle way back in terms of total power and pulse width to the motor.
AC motors also generate heat in the rotor due to the induced (hence inductive AC motor) field, DC motors are primarily generating heat in the windings.

So its basically like stalling a motor, but with a low enough power level that it doesn't burn up. If the motor is normally 95% efficient, you can only get 5% of power capability out of it in the form of heat. (less if the motor runs it's own cooling pump)

Hope that helped.

Not on the model 3. That car has a permanent magnet motor and has no rotor currents therefore no rotor current losses.

 

[mongo]

Not on the model 3. That car has a permanent magnet motor and has no rotor currents therefore no rotor current losses.

Ah, this is the Model 3 forum so I could have been more explicit in calling out the difference and that the 3 is a PM brushless motor.

AC motors also generate heat in the rotor due to the induced (hence inductive AC motor) field, DC motors are primarily generating heat in the windings.

 

[scaesare]

My S can take 45 minutes to heat up to Max charge rate when it's cold.

So it looks like the Model 3 may be on par with the S in terms of heating time.

Despite the lesser heating energy available the car may be able to heat that pack at about he same rate.. perhaps to lesser pack mass, different insulation properties, etc...

 

[scaesare]

It is a physical feature of Lithium batteries that plating can occur if charged at very low temperatures so Tesla are just being responsible. It just means that you have to allow a little extra time if charging a cold car. I think it is a sensible move forward to lose the weight and extra parts complexity of a dedicated battery heater. The model S will delay charging to heat the battery first, but the dedicated heather just works a little quicker. Telsa Bjorn has shown that if you are in a rush, it is best to drive a cold-soaked car 60miles before charging. If not in a rush then just charge the car overnight and let the BMS do its thing.

In the Renault Zoe they use the motor as a transformer for 43KW AC charging, maybe that is next for the model Y; to have the motor act as motor/generator/heater/transformer

The early Roadster designs based on the AC Propulsion intellectual property went this route. They ultimately abandoned it in subsequent designs...

 

[brkaus]

Next time the temp drops (darn, I missed opportunity last week), I'll leave my S out and then look outside/inside with a FLiR imaging camera. Might see hot spots or a warm floor.

I have found it odd that I have never observed the cabin temp below ~40. Never investigated.

 

[scaesare]

Next time the temp drops (darn, I missed opportunity last week), I'll leave my S out and then look outside/inside with a FLiR imaging camera. Might see hot spots or a warm floor.

I have found it odd that I have never observed the cabin temp below ~40. Never investigated.

While charging?

I've had my app report much colder than that in the cabin...

 

[navguy12]

I guess I didn't realize that was the case. Do you have a link to that? Because under normal freeway driving (cruising), it would take about 30 minutes or so to warm up the pack. It would be an incredibly efficient motor if it was unable to provide sufficient heat to the battery pack!

Just going thru this whole thread today, I can add a data point: Test drive at Kingston ON supercharger 15 days ago, -20C, You You's TM3 had just completed a 90 minute run at speeds over 100 kph. He had "about 5%" when initially plugged into the supercharger and 1+23 later, had "about 65%".
Whatever plan is being used to heat a TM3 battery so it can take a fast charge.......it doesn't work (as of 15 days ago, anyways)

 

[jsmay311]

Another testing opportunity!

Someone who owns both an S (or X) and a 3 who lives in a cold climate and lives relatively close to a Supercharger...

When there's going to be a cold (well below freezing) day, get both vehicles' batteries drained down to a similar level -- let's say 20%. Let them cold soak unplugged outdoors for ~12+ hours overnight. The next morning, along with a partner, drive them to the Supercharger in the morning and plug in. Record and compare charge rates.

(If you could access battery temps and record those too, that'd be even better.)

 

[jsmay311]

Test drive at Kingston ON supercharger 15 days ago, -20C, You You's TM3 had just completed a 90 minute run at speeds over 100 kph. He had "about 5%" when initially plugged into the supercharger and 1+23 later, had "about 65%".

"1+23" = 1 hour 23 minutes, I take it? (Never seen that format before)