Deep dive into Tesla power electronics

Discussion in 'Tesla' started by bwilson4web, May 4, 2021.

  1. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I have been skeptical of the CCS-1 and even the J1772 because they are larger and often less capable than the Tesla connector. This Weber State YouTube is a deep dive behind the technology:



    To compare and contrast:
    • J1772 vs Tesla - J1772 is larger. Although the J1772 spec reports up to ~80 A DC capable, there are no know J1772 with both AC and DC capability much less any non-Tesla EVs that take DC via the J1772.
    • CCS-1 vs Tesla - at least three times the face area, an extra DC pair, it is heavy. Deployed, we find 350 kW fast DC chargers with up to 800 V, if capable. So then a typical, non-Tesla EV plugs in too often limited to 50 kW.
    • Tesla vs rest - a bluetooth transmitter will open the charging access port. There is no second charge port cover to manually remove. The protocol to charge back to the car's owner credit card is universal versus a collection of charger specific cards or generic credit card.
    Bob Wilson
     
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  2. hill

    hill High Fiber Member

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    One thing I never bothered to read up on is the tech that allows the model X & S charge port doors to open up automatically as the owner brings the Tesla nozzle close to the charge port door. Even the 240v HPWC at home does this.
    It's soooo unnecessary .... but 'cool' nevertheless.
    .
     
  3. Trollbait

    Trollbait It's a D&D thing

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    Isn't that true of most luxury features?
     
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  4. Mendel Leisk

    Mendel Leisk Senior Member

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    Auto-folding mirrors...
     
  5. bwilson4web

    bwilson4web BMW i3 and Model 3

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    The auto-charge door responds to a Bluetooth signal that pressing the handle back actives. But ordinary J1772 lack the Bluetooth circuit. In contrast to a manual mechanism like our BMW i3, the automatic system has consistent open and close stress and strain.

    Bob Wilson
     
  6. hill

    hill High Fiber Member

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    & with defrosters .... & proximity flashers, & integrated blind spot cameras. Hate to hear what these things go for.
     
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  7. dbstoo

    dbstoo Active Member

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    I thought there was going to be discussion of the technical specs. :(

    I'm impressed by the well thought out handshake of the J1772 interface. While it is designed for lower power levels than a modern Tesla, the batteries used in cars were much less capable when the J1772 standard was developed. Obviously, the lower power levels were meant for cars that did not commute hundreds of miles a day. I could travel 100 miles a day and easily recharge off a J1772 level 2 charger each night.

    Tesla was smart to make the charge port J1772 protocol and signal compatible, even though they made the plug itself deliberately incompatible with the public infrastructure. It sort of smacks of selfishness to set up your cars to use locally provided resources (chargers) while prohibiting other cars from using the Tesla chargers. Of course, nothing in the modern ethos prohibits selfishness, especially when there are no repercussions.

    It's neat that tesla chose to use Bluetooth as an "open sesame" signal. BT is easily spoofed, copied and corrupted but a BT chip is dirt cheap and routines to work with them are widely available in the public domain.
     
  8. bwilson4web

    bwilson4web BMW i3 and Model 3

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    I bought a copy of the J1772 standard. My understanding is it was derived from a power utility protocol. As for my 55 kWh Model 3 and 18 kWh BMW i3-REx, overnight is long enough for a 100% charge their batteries. But I've also tried a 120 mile benchmark using just L2 chargers ... it was miserable.

    Tesla has publicly offered a SuperCharger license to any how would support the capital expense of building the network.

    There are operational modes where the signal will not open the charging flap.

    Bob Wilson
     
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  9. Rmay635703

    Rmay635703 Senior Member

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    The Volt charger will run off DC in its specified 90-250 vDC range (as validated by a guy in Europe)

    Trouble is finding an EVSE to handshake or even operate on dc but the charger itself will run.

    Also supplying DC to a Volt will not allow any faster charging, might be useful to HV solar though
     
  10. bwilson4web

    bwilson4web BMW i3 and Model 3

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    As a general rule of thumb, any switching power supply will run off of DC as well as AC. But it will still 'chop' the input to generate a regulated, DC output.

    The classical, switching power supply starts with a full-wave rectifier into a filter cap. That leads to significant inrush currents that can (and have) tripped 12V-to-120VAC inverters that I have personally witnessed and debugged. I used a thermistor to limit the initial current but there is waste heat.

    Bob Wilson
     
  11. Fred_H

    Fred_H Misoversimplifier

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    If I recall correctly, at the time the Tesla charging plug was designed, there was no existing standard for charging plugs that met the requirements of supercharging. Tesla was forced to either develop a better plug, or debilitate the future cars and Supercharger network with the available standard plugs. So I don't understand why Tesla choosing to not cripple itself with obsolete technology would be considered selfish.
     
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  12. 2k1Toaster

    2k1Toaster Brand New Prius Batteries

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    There have been 4 or 5 times over the past 8+ years with my Leaf where I have gotten to the charge port door and realized I forgot to open it with the inner release button. Each time was mildly frustrating and I wish it had BLE opening! :)
     
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  13. Trollbait

    Trollbait It's a D&D thing

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    CHAdeMO was the only other standard in the US at the time, and it may have been limited to just 50kW back then. They also charged licensing fees to use it.
     
  14. dbstoo

    dbstoo Active Member

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    Sort of. Look at the offer and you will see that it includes a clause that gives Tesla the right to use the intellectual property of the other company with indemnity in exchange for the use the tesla designs.
     
  15. bwilson4web

    bwilson4web BMW i3 and Model 3

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    Would you have a link to the offer?

    I was going by news reports, not the actual offer. Of course the obvious question is whether or not the other company has any intellectual property worth having.

    Bob Wilson
     
  16. Trollbait

    Trollbait It's a D&D thing

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    Many licensing agreements between companies involve a license swap.
    Toyota wanted BMW knowledge with carbon fiber, so traded fuel cell expertise for it for example.
     
  17. dbstoo

    dbstoo Active Member

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    It's in one of my posts back when when this was last discussed. Maybe late last year???
     
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