TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC

9kW "stator heater" ON when supercharging. Hypocritical waste?

Discussion in 'Model 3: Battery & Charging' started by googlepeakoil, Jan 7, 2020.

  1. googlepeakoil

    googlepeakoil Member

    Joined:
    Mar 6, 2015
    Messages:
    289
    Location:
    England
    #1 googlepeakoil, Jan 7, 2020
    Last edited: Jan 7, 2020
    So for a decade we've been told that active battery management of lithium batteries is good. Lithium batteries (for their longevity) like to stay around the same temperature as humans, 20C. Nissan don't have liquid cooling and suffer range loss in hot states (Arizona where some lost 30% range in 1-2 years, and chargegate where they can't cool the battery). Monitoring tech showed temperatures of 45-55C and charging speed curtailed to prevent overheating.
    But crazily we now see in a newish Bjorn Nyland video like below that Tesla is actually using 9kW of "heaters" to heat the battery to an insane 50-55C while the car is stationary, sat supercharging!! Not just at the start, but 10-15minutes into the session! The battery is approaching 50C and the heaters are still heating it more and more! Wasting massive amounts of energy imho.
    It "has" to be detrimental to the life to heat it that much!

    So - just to be clear, this is not a battery being left to heat up to 50C by the process of charging. That would be okish. The car is actually "diverting" an extra 9kW (4.5kW per drivetrain) of power on top of the 120+kW from first the battery (while approaching the charger), then at the supercharger to the motor stator(s) to heat the battery long into the charge session. So Bjorn has an OBD tool monitoring 100+ sensors - and it's right there in the display. 4.5kW energy used per drivetrain! Bjorn is even aware of it, calls them the preheat "afterburners". That Tesla run the motors inefficiently to overheat the stators and run the coolant loop as heaters.
    I'm amazed this isn't a bigger environmental scandal from a company that "claims" to be the best course for us to prevent waste, global warming, and clean energy, but here we have a massive 9kW of electricity (enough to run 9 average European houses - 1kW is average for Europe, 2kW for the US) just being used to speed the charge time up by a few minutes! This is not an insignificant "waste". This is 9kW per supercharger, and there's 15,000. Of course the second the car leaves the supercharger it's then wasting more energy to actively cool the battery it just cooked! The coolant flow rises to max speed, the inflow temp drops to about 10C below the battery temp and it tries to now cool the battery, 30minutes later the battery is back to circa 25C.
    So this is 9kW just to heat the battery - not chemical energy of electrons for more miles - this is just "thermal" energy dumped to the atmosphere from a heater, then re-dumped by the radiator (coolant).
    Now recall this is Tesla. When Elon lectures us about global warming, heating the planet, the need to go solar, wasting energy, etc. So is this technical solution not slightly ironic for a company claiming to be all about efficiency and preventing waste? I recall the slogan of Google. "Don't be evil". Tesla's motto is about fun, but also energy efficiency. I think this is a massive violation of. It's like Greenpeace leaving patio heaters on outside their offices!
    I imagine the batteries at 50C can charge quicker than at 20 or 30C - but heating to 50C then cooling them to 20C is such a waste of energy!
    First I don't think Tesla should do this - it's a bit "evil" in the Google thinking.
    Secondly, charging a battery heats it anyway, don't heat it to 50-55C with a 9kW heater as well. This is insane.
    I'd like a setting not to heat the battery - I might not be in a rush. It's wasteful at best, evil at worst. Don't be evil !!

    For more on the OBD variables (battery temp, coolant inflow, outflow, stator front / rear) and 100+ others, there's also this video.
    See video here regarding OBD -
     
    • Disagree x 13
    • Funny x 3
    • Love x 1
  2. googlepeakoil

    googlepeakoil Member

    Joined:
    Mar 6, 2015
    Messages:
    289
    Location:
    England
    Tesla I thought was all about the fight against big auto, big oil, and wasted energy imho - but at the same time having fun.
    We've now seen them create a truck even bigger and more menacing than any other truck (with no crumple zone) which imho is going to lead to bigger and heavier trucks using more energy, and I am reminded of the phrase:
    "He who fights with monsters might take care lest he also become a monster." (Beyond Good and Evil, Aphorism 146)
     
    • Disagree x 9
    • Funny x 2
  3. Runt8

    Runt8 Active Member

    Joined:
    May 19, 2017
    Messages:
    1,986
    Location:
    Colorado
    Where was it stated that the Cybertruck doesn't have crumple zones?
     
    • Like x 3
  4. Electric Dream

    Electric Dream Pilots the Millennium Milkfloat

    Joined:
    Jul 21, 2016
    Messages:
    1,527
    Location:
    UK
    The pack is heated during charging to increase the charging rate and prolong the battery life.

    It might be a waste of energy to you, but it's done for good reasons. Better long term efficiency is sometimes preferable over short term efficiency and apparent energy savings.
     
    • Like x 4
  5. Daniel in SD

    Daniel in SD Well-Known Member

    Joined:
    Jan 25, 2018
    Messages:
    6,281
    Location:
    San Diego
    Supercharging is all about charging as quickly as possible. How much extra energy does this use? I bet it's a tiny compared to vampire drain (the real scandal! :p).
    I imagine if you use urban superchargers it won't need to heat the battery. It's probably best to use home charging off peak from an environmental standpoint.
     
    • Like x 1
  6. DirtyT3sla

    DirtyT3sla Member

    Joined:
    Apr 17, 2019
    Messages:
    521
    Location:
    Holly
    As for this part, if it was detrimental to the battery, Tesla wouldn't do it. And there are plenty of Model 3s with 10s of thousands of miles and little to no degradation, so I'd say the batteries are fine.

    As to your bad for the environment part... I get it, but imagine the cars take even longer to charge than they do (and imo the charging speed is plenty fast, but when people hear 20m they immediately relate it to gas being 3m and think it's bad, although they don't take into account bathroom breaks, food... ok I could go on forever, but you get it).

    Now Tesla sells less EVs because their even slower charging speed. More pollution. I think this is a non-issue.
     
    • Like x 4
    • Funny x 1
  7. SigNC

    SigNC Active Member

    Joined:
    Aug 23, 2017
    Messages:
    1,441
    Location:
    NC
    Go through a winter without pack heating and trying to fast charge and see how much you care about the 30 cents in wasted electricity.
     
    • Like x 5
    • Funny x 2
  8. MrMassTransit

    MrMassTransit Supporting Member

    Joined:
    Mar 7, 2019
    Messages:
    299
    Location:
    Washington, DC
    The other factor from an environmental perspective is that battery packs require significant energy to produce and recycle. Therefore, if Tesla can take actions that notably preserve their life, that may not all be wasted energy if it preserving the life of the pack.
     
    • Like x 4
  9. StellarRat

    StellarRat Active Member

    Joined:
    Jan 8, 2014
    Messages:
    1,488
    Location:
    Pacific
    How do you know there is no crumble zone? Just because it isn't as visible does not mean it's not there. Tesla prides itself on building very safe cars. I can't imagine the truck won't be the same.
     
    • Like x 4
  10. mongo

    mongo Well-Known Member

    Joined:
    May 3, 2017
    Messages:
    12,789
    Location:
    Michigan
    Heaters were running at 7kW total and shut off when pack reached ~43C.
     
    • Informative x 1
    • Like x 1
  11. 804son

    804son Member

    Joined:
    Jun 26, 2019
    Messages:
    10
    Location:
    Colorado
    Acceptance and Adoption should be the real goals here, if faster Supercharging by preheating the battery, leads to better acceptance and adoption of BEV's then the energy savings in the long run will be far more beneficial.
     
    • Like x 4
  12. ZOMGVTEK

    ZOMGVTEK Member

    Joined:
    May 19, 2015
    Messages:
    558
    Location:
    'Merica
    Without heating you increase lithium plating, which is more likely to degrade the pack faster than the temporary elevated temp. In addition to this, the charge speed is S L O W when the battery is very cold, which means many hour charge cycles, angry customers, and more stalls need to be installed in cold climates.

    Personally, I would much prefer more heating power. The car won't charge at all when the pack is somewhere around freezing, and a bit above that the charge rates are in the single digits.
     
    • Like x 2
    • Informative x 1
  13. Puddles

    Puddles Member

    Joined:
    Jun 2, 2017
    Messages:
    728
    Location:
    Fresno, CA
    These guys are right, we don’t have proof of this, but it’s a reasonable concern given the materials and Elon’s comments about the way the body is engineered to be structural. I interpret this to mean “rigid.” OTOH, Tesla engineers have proven to be a clever people. I for one am dying to see the crash test videos. They should be even more fascinating than the ones of the model 3’s.
     
    • Like x 3
  14. Kirby64

    Kirby64 Member

    Joined:
    Jun 28, 2018
    Messages:
    485
    Location:
    Austin, TX
    Heating the batteries has a purpose. 9kW of heat isn't a lot, anyways. I think you underestimate how much it costs to heat a house, by comparison. You mention that the 'average european house' uses 1kW. That's ON AVERAGE. Instantaneously power usage is way way higher. Hell, even a kettle in Europe is going to be over 3kW. And that's to heat 1L of water quickly. Most heating systems for houses use tons of power. If they aren't gas powered or heat pump powered, using >20kW during heating isn't unusual. I personally know a friend that has 40kW of strip heaters for heating his house.

    The alternative is to have a car that supercharges incredibly slowly in the winter. Which means less people get to use Superchargers, less interest in using them, and less overall interest in buying Tesla's (since their cars would charge slowly). If your goal is to cut into climate change as quickly as possible, having people buy more EVs will do more good than any 'cost' of heating the batteries. And that's ignoring the benefits in battery longevity, etc, from heating the battery properly.

    Also, you might not be in a rush, but plenty of people are... so hogging a SC station because you don't want your battery warmed is just wasting other people's time if the stations are full. If you want to charge it slowly, charge at home.
     
    • Like x 2
    • Informative x 1
  15. googlepeakoil

    googlepeakoil Member

    Joined:
    Mar 6, 2015
    Messages:
    289
    Location:
    England
    #15 googlepeakoil, Jan 9, 2020
    Last edited: Jan 9, 2020
    The cars exoskeleton appears to be the structure. That was evident from the video. Ok it might be a bit thinner at front/rear to crumple - but it doesn't look that way. But the more it crumples the more it writes itself off as there appears to be no seams. And further - I don't see how the vehicle is actually repairable.
    I reckon <5mph. Truck survives. Minor scuffs.
    5-15mph. Only option - bash dent out. You can't swap out the panels like a regular vehicle!
    15mph+ gut the car and move the parts to another chassis!
    But due to the weight (3-4 tons?) and it's tough shell it's going to smash up any vehicle it hits like an eggshell (unless the thing it hits is concrete). It's going to be more dangerous to other road users than a Hummer. Of course active safety might reduce the chance of an impact - but I don't fancy being in anything T-boned by it.
     
  16. arghx7

    arghx7 Member

    Joined:
    Aug 6, 2019
    Messages:
    432
    Location:
    Michigan
    Early ICE emission controls would run the engine rich to combust emissions in the exhaust manifold using an air injection pump. It was called a thermal reactor system and it was a popular emission control in the 1970s as catalytic converters were just being developed (old Porsches for example used them). The result was cleaner tailpipe emissions at the expense of fuel economy. Eventually technology moved on. I suspect in 5 or 10 years we'll have batteries that won't need as much energy expended in heating for fast charging.

    People complain about charging times preventing them from buying EV's, so Tesla makes the car charge faster. Yeah it uses energy. There's no free lunch. If customers don't accept the product they will just go back to ICE cars.

    You don't have access to their durability test data to know what is an acceptable amount of time at 50C for battery degradation. It's simply not possible for us to judge without inside information.
     
    • Informative x 1
    • Like x 1
  17. googlepeakoil

    googlepeakoil Member

    Joined:
    Mar 6, 2015
    Messages:
    289
    Location:
    England
    Heating the battery from negative infinity to 15/20C = sensible. Yes, it's well known cold batteries can't charge/discharge at even a fraction of "1C" and so even regen is limted.. But continuing to heat the battery with 9kW of power (10% of the chemical charging power) when it's 30,40,45+ C - that seems wasteful imho. The power is already tapered from 200kWh to aprox 100kWh. It is literally heat that will then be dumped to the atmosphere on top of the heating from the physical act of throwing the trillions of electrons at the pack.

    Amusing fact - did you know a charged battery weighs about a microgram more than an uncharged battery :
    Does the mass of a battery change when charged/discharged?
    Are Batteries Heavier When They're Full? (with Robert Llewellyn!) | Tesla
    You have to rework E= m c2 gives
    energy in Joules / speed of light squared.
    50,000wh x 3600 / (speed of light squared) = tiny number!!!
     
  18. donkemaen

    donkemaen Member

    Joined:
    Aug 10, 2017
    Messages:
    30
    Location:
    Norway
    • Informative x 3
  19. qdeathstar

    qdeathstar Active Member

    Joined:
    May 17, 2019
    Messages:
    1,803
    Location:
    VB
    I put miniature windmills on my Tesla to offset the heater as well as using a solar powered calculator and wrist watch...
     
    • Funny x 3
    • Like x 1
    • Love x 1
  20. Az_Rael

    Az_Rael Supporting Member

    Joined:
    Jan 26, 2016
    Messages:
    5,599
    Location:
    Palmdale, CA
    Depends on if you think Tesla tests long term or not before they implement stuff like this or if they are responding to shorter term motivations to sell cars today. They currently appear to be figuring out the limits of the 18650 BMS algorithms over longer terms and imposing capped supercharger rates and capping max voltages to older cars “to extend battery life”. Hard to look at that and not be somewhat concerned about this push to ever greater charging speeds on the newer cars.

    Maybe Tesla has it all sorted out this time, guess we will find out.
     
    • Like x 2

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC