Information about the Model 3 battery vs Model S\X

[taraquin]

Being the geek that I am, technical stuff has always been interessting. Getting my Model S was like moving into geek-heaven. There are several aspects of Teslas that interests me, the battery and BMS is one of them. If other with more knowledge than me are willing to contribute with info and correct me I would appreaciate it, perhaps this could be interessting for fellow geeks If anyone has gotten CANBUS-read on temp-targets etc it would be great if you post it.

Pros of the battery and BMS of the Model 3 vs S\X:
+ Better for the environment due to less use of cobalt and more use of silicon.
+ Cheaper to build, parts due to using less cobalt.
+ Easier maintenance accesible below back-seats due to most components being integrated (charger etc), on S and X battery must be removed from car.
+ Better performance at low temperatures, from what I have read\heard from other users, without preheating\charging, battery allows for some regen down to about -5C. In Model S and X 0C is the limit for regen, and below 5C regen is very limited.
+ Less complicated since motor can heat battery (2.4-4kW of waste heat?) instead of using an external element (up to 6kW heat on S and X). After my batteryheater on my S became unstable and did not start every time before I got it fixed at service I really missed having different heating-options.

Cons:
- No way to control battery-heating like in S and X where you can use range mode to disable\enable. If range mode is ON, then battery will heat if temps are about -10C or below. In S and X: If range mode is OFF, battery will heat up to around 10C (differs with SW-versions) and you then have about 30kW of regen. On short trips without preheating this causes horrible consumption so many owners use range mode ON on short trips. When batterytemp is around 16C or higher, which is done with waste heat, you will get the full 70kW-regen. This is a bit complicated, and I understand why Tesla would make it less complicated, but some degree of user-control would be most welcome in 3.
- Supercharging in winter is not optimal since the battery takes a lot longer time to heat than the S and X. If Tesla would start motor to generate waste heat during supercharging this could help a lot (maybe new SW has improved this?). There will be longer waiting-lines at SCs in the future if this is not improved.
- Battery can to my knowledge only be heated by waste heat from drivetrain during driving since motor only can generate direct waste-heat when standing still.
- You need around 90% or less SOC in order to gain max regen even if temp is ideal. Performance on high SOC is worse than S and X. On S and X you can get full regen above 95% SOC if temp is good, after full charging in summer I have seen full regen even at 98% SOC in my S.

Overall I like what Tesla has done with 3s battery. They have reduced cost and enviromental impact compared to S and X. Performance at low temps are improved. Biggest issue seems the lack of user control wile preheating and supercharging. A more aggressive approach, possible to control by user like in S and X which can improve regen\charging capabilities while preheating\precharing would be great. For short trips there is no problem, but going on long road-trips at least starting motor to make waste heat to improve charging speed would be most welcome.

Some of this might be incorrect, I apologize if some of the info is wrong. I don`t have a Model 3 myself so all of this comes from reading different articles, talking with owners, watching youtube-reviews etc. I might have missed some importat differences as well, feel free to correct me and leave feedbacks. I will update this post from time to time

 

[remlemasi]

Good info. First suggested update: CTRL-F “engine” and replace with “motor”

 

[taraquin]

Good info. First suggested update: CTRL-F “engine” and replace with “motor”

Will do if I am able to, appears I can`t edit my post anymore, spend a few minutes now on finding out how and it turns out I can edit my own post. I have to ask a mod to help me :/ I really like the TMC-foum, but not being able to edit my own posts is a thing I really dislike about it...

 

[cbutters]

Will do if I am able to, appears I can`t edit my post anymore, spend a few minutes now on finding out how and it turns out I can edit my own post. I have to ask a mod to help me :/ I really like the TMC-foum, but not being able to edit my own posts is a thing I really dislike about it...

Also it is Cobalt; not "Cobolt"

 

[ohmman]

mod note: some typos/words edited for @taraquin by request.

 

[taraquin]

mod note: some typos/words edited for @taraquin by request.

Thank you

 

[BestHand]

Biggest issue seems the lack of user control wile preheating and supercharging. A more aggressive approach, possible to control by user like in S and X which can improve regen\charging capabilities while preheating\precharing would be great.

I think that Tesla gave less user control on purpose. Too much control will lead to more battery fails, and why Tesla need this headache? Unfortunately most owners not really have great knowledge about battery. Also, Tesla want to make ownership as less confusing as possible. Now imagine average person met an interface with numbers of switches and settings. From the Tesla point of view the less is better. I also want to have more settings, the same as you, but I can see the Tesla's point.

 

[taraquin]

I think that Tesla gave less user control on purpose. Too much control will lead to more battery fails, and why Tesla need this headache? Unfortunately most owners not really have great knowledge about battery. Also, Tesla want to make ownership as less confusing as possible. Now imagine average person met an interface with numbers of switches and settings. From the Tesla point of view the less is better. I also want to have more settings, the same as you, but I can see the Tesla's point.

I meant like range mode in S and X which changes a lot of values and for instance allows for higher temps. A general fix which heats battery while supercharing to improve charge speed would be most welcome.

 

[BestHand]

I meant like range mode in S and X which changes a lot of values and for instance allows for higher temps. A general fix which heats battery while supercharing to improve charge speed would be most welcome.

Let say it allows higher temperatures. You then damaged the battery after setting temperature too high. Will you take responsibility? A lot of people have no idea how things work and they do not have to. Allow them to play with the settings and you will pay for all damages they will make.

 

[Big Earl]

Cons:

1. - No way to control battery-heating like in S and X where you can use range mode to disable\enable. If range mode is ON, then battery will heat if temps are about -10C or below. In S and X: If range mode is OFF, battery will heat up to around 10C (differs with SW-versions) and you then have about 30kW of regen. On short trips without preheating this causes horrible consumption so many owners use range mode ON on short trips. When batterytemp is around 16C or higher, which is done with waste heat, you will get the full 70kW-regen. This is a bit complicated, and I understand why Tesla would make it less complicated, but some degree of user-control would be most welcome in 3.
2. - Supercharging in winter is not optimal since the battery takes a lot longer time to heat than the S and X. If Tesla would start motor to generate waste heat during supercharging this could help a lot (maybe new SW has improved this?). There will be longer waiting-lines at SCs in the future if this is not improved.
3. - Battery can to my knowledge only be heated by waste heat from drivetrain during driving since motor only can generate direct waste-heat when standing still.
4. - You need around 90% or less SOC in order to gain max regen even if temp is ideal. Performance on high SOC is worse than S and X. On S and X you can get full regen above 95% SOC if temp is good, after full charging in summer I have seen full regen even at 98% SOC in my S.

1. You can actively heat the battery by navigating to a Supercharger.
2. See above
3. In addition to heating the battery when the vehicle is stationary, the motor can heat the vehicle while it's in motion. It's more than just "waste" heat. The system can generate up to 4 kW of heat just for the battery, although I've only seen up to 2.5 kW while stationary and I have no way of measuring it while moving.
4. Regen is a function of state of charge and temperature. It can do more regen at higher states of charge if the battery temperature is warmer than if it's cold. I haven't charged above 90% enough at various temperatures to quantify how strong it is in various conditions.

 

[taraquin]

Let say it allows higher temperatures. You then damaged the battery after setting temperature too high. Will you take responsibility? A lot of people have no idea how things work and they do not have to. Allow them to play with the settings and you will pay for all damages they will make.

I`m not saying that, I just stated what Tesla allow in the S and X (they don`t even inform the user that using range mode allows for the battery to heat to above 40C), and also many Model 3 owners report poor chargingspeeds at SC. My only suggestion was for instance adding a "range mode" which basically does the same, but allow the battery to reach above 40C is by no means something I hope they do.

 

[taraquin]

1. You can actively heat the battery by navigating to a Supercharger.
2. See above
3. In addition to heating the battery when the vehicle is stationary, the motor can heat the vehicle while it's in motion. It's more than just "waste" heat. The system can generate up to 4 kW of heat just for the battery, although I've only seen up to 2.5 kW while stationary and I have no way of measuring it while moving.
4. Regen is a function of state of charge and temperature. It can do more regen at higher states of charge if the battery temperature is warmer than if it's cold. I haven't charged above 90% enough at various temperatures to quantify how strong it is in various conditions.

1,2,3. Ok, thx for the update and info. I was not aware that the motor could generate heat while driving except for waste heat and that the "waste-heat-mode" only occured when standing still. Still, many owners in winter report getting quite low charging-speed at SC even after charing for a long time. A couple of owners reported that they arrived at SC with almost full regen (outside temp 0-5C) and charged from about 20% SOC up to 60 and still only got about 40kW all the way. Things might have improved with the latest SW-updates, but in my Model S charge-speed rises rapidly even in -10C or colder and stays at 60-80kW in the same scenario (entering SC without full regen).
4. Yes, I`m aware of that, but some owners report not getting full regen in summer-temps when SOC is around 90%. Could be the other way around as well that temps at the current SOC is too high to allow for full regen, experienced that a few times in my Model S.