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EVSE Temperature Issues

Discussion in 'Charging Standards and Infrastructure' started by W.Petefish, May 16, 2012.

  1. W.Petefish

    W.Petefish Active Member

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    Been there. Done that.

    Tesla said that the Model S has liquid cooling for the PEM, Motor, and Battery. So, heat shouldn't be an issue. (or so they say)
     
  2. grisnjam

    grisnjam P6316

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    The real question is how many kWh will be needed to cool a Model S sitting in 100+ degree summer heat for 6+ hours. I live in Austin, Texas and in the summer (60+ over 100 days last year) my car is parked in the sun while at work so this is a real concern.

    The 40 kWh pack is really all I think I need pure range-wise but I am a bit worried about 4 years on, in the the sun what my range will look like. Good news is I am late in general production so there should be plenty of first hand reports by then but this might push me to the 60 kWh.
     
  3. Robert.Boston

    Robert.Boston Model S VIN P01536

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    #3 Robert.Boston, May 16, 2012
    Last edited: May 21, 2012
    [moved from the World Map thread]
     
  4. vfx

    vfx Well-Known Member

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    New thread please:

    EVSE Temperature Issues

    I had not heard of the 'charge box" overheating but can easily imaging a western sun baking the electronics enough that it might trip a breaker when electricity starts flowing.

    Could an EVSE equally freeze in enough cold that it would not work?
     
  5. hcsharp

    hcsharp Active Member

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    #5 hcsharp, May 18, 2012
    Last edited: May 20, 2012
    There is a temp sensor in the HPC that will stop the charging if it gets too hot. Not sure if the UMC has a temp sensor or not.
    I've never heard of one getting too cold but my first home-made UMC had an opamp (electronic chip) that was only rated down to 0C. Whenever it got down near freezing the output of the opamp would go out of spec and think the car was plugged in when it wasn't. I eventually replaced the chip and I'm careful now to only use components that are rated -40C to at least +105C.
     
  6. doug

    doug Administrator / Head Moderator

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  7. Doug_G

    Doug_G Lead Moderator

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    I'm finding this a bit dubious. An EVSE doesn't consume significant power, and therefore doesn't generate significant heat. It's basically a safety switch, and it uses contactors that are quite capable of carrying the current without much loss. So it should be quite straightforward to design the electronics to withstand the outdoor environment.
     
  8. hcsharp

    hcsharp Active Member

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    You would think. The contactor coil consumes less than 3 W when connected to the car and there is a power supply 5V and +-12V which presumably consumes a couple of watts. Combine that with baking the box in direct sun when it's 110 deg F (43C) outside and you can see how the inside of the housing could reach 70 C. That might be kind of a low shut-down threshold but you can see how it's possible.

    Not sure if they used SSRs in any of those but they will waste a lot more heat than a contactor but only when charging. With SSRs I could envision reaching 90C inside the box which would not be an unreasonable cut-off point.
     
  9. W.Petefish

    W.Petefish Active Member

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    True. In that instance the EVSE would need to have an external sink for heat.
     

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