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Charging rate drops from 32a to 5a

Discussion in 'Model S: Battery & Charging' started by robaross, Oct 27, 2013.

  1. robaross

    robaross P4550

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    Started at 148 miles, 32A UMC 50A breaker. At 168 miles I checked app and charge rate had dropped to 5A. This is not the first time this has happened. No charging error on dash. Removed UMC, reset to 32A and reconnected UMC. Waited for charging to start and it went up to 32A, 248V, 24mph. Any thoughts?
     
  2. JPP

    JPP Active Member

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    Temperature? Where are you located/charging? Slightly loose connection between UMC and charge port? What color was the ring around the charge port and was it pulsing (fast or slow)?
     
  3. efusco

    efusco Moderator - Model S & X forums

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    Sometimes if the charge plug is not completely locked into the charge port it will do that...it allows a trickle charge, but not a full power charge. I would release it, unplug, then replug and then tug on it to be sure it's fully locked.
     
  4. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    What did the car show when you looked at it? Did it show 5A/5A, or 5A/32A, and did you try to adjust it upwards?

    In addition to Evan's suggestion, I've seen 3 more situations --

    1) At my home, the car has detected 3 different charging addresses, and remembers the setting for each of them independently. I had previously set the charge current lower. The car showed 32A/32A but I could adjust it upwards.

    2) Having the UMC outside where the sun heated it up caused the UMC to reduce the current in the pilot signal, and the car showed 8A/8A. I could not adjust it upwards when I tried.

    3) When the car comes close to a full range charge, it ramps down and will show 57A/80A, decreasing as it gets full.
     
  5. cinergi

    cinergi Active Member

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    I've seen this happen before (and there's a thread on here about it) where the limit drops to 5A ... EdA had this happen to his car ... there was a message on his screen but I'm forgetting what it was. Unplugging and plugging back in fixed it. I don't think anyone's managed to explain it yet. Lack of pilot seems to get you 16A so I don't know where 5A is coming from.
     
  6. robaross

    robaross P4550

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    In garage in SFL, probably 80's. Ring starts blue, screen says charge will start soon, then changes to fast pulsing green and charging begins. Started at 32A/32A, when checked later 5A/5A. UMC on wall in garage, never outside. No error messages. Removed UMC and restarted atfer resetting screen to 32A. Completed charge without problem. Just something to live with or a problem?
     
  7. EdA

    EdA Model S P-2540

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    Gosh, my memory is bad, was this really me?
     
  8. Longhorn92

    Longhorn92 MS VIN #10103 (40 kWh)

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    I had/have this problem as well, and mine also was/is not a connection issue (I always firmly push the connector into port and wait for dark green flashing light). I took it into the service center a few months ago and thought it was fixed; however, it just happened again yesterday. I have my theory, but a few questions for you:
    1. Do you have this issue only at one charging location or has it happened at multiple charging locations?
    2. If you do not reset the screen to 32A, but just unplug and plug back in, does it still limit it to 5A?
    3. Have you ever manually set the charging limit to 5A in the past at this charging location (home I assume)?

    Here is what happened to me:
    1. Took the family to France for a two week vacation, and so I set the charging limit to 5A while we were gone.
    2. When I returned I changed the charging limit back to 40A.
    3. Within a few days, the charging limit automatically changed back to 5A.
    4. I reset the charging limit again to 40A.
    5. It happened another two times over the next week, and I realized that it was happening in the middle of charging (i.e. it would start at 40A, then automatically switch to 5A sometime during the charging session).
    6. My troubleshooting consisted of (i) making sure I firmly pushed in the charging cable, (ii) charging at a different location after no reset of the charging limit (worked fine at 40A), (iii) soft rebooted the computer, (iv) reset UMC (button on back), and finally, (v) taking the car to the service center.

    By the way, I can only charge to 72% (software-limited 60 kWh car), so it is not some automatic lowering of amps when getting close to full charge. Plus, that shouldn't change the actual charging limit anyway.

    Here is what I think/guess happened in my situation: since the charging limit is location-based (GPS), I think the car's GPS location was slightly different when I set the 5A limit to when I cleared/reset it back to 40A upon return 15 days later (even though the car didn't move). So, I believe that there is still some residual/phantom charging limit location in the system that activates every once and a while when the GPS is slightly off (in a similar fashion to when I originally set it).

    I have asked Tesla to completely clear all location-based settings in the car, but their response has always been pretty vague as to whether or not they have been able to accomplish this.

    @robaross: it would be interesting to know if, after your car switches to 5A and you do NOT reset the screen to 32A, does another charging location still limit you to 5A?
     
  9. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    I can confirm this happened to me several times... parking my car in the driveway just outside the garage vs. parking my car in the garage bay itself generates a different address for charging, and at one time it picked up the old 40A setting from when I had the UMC (vs. the HPWC now).

    That's why I ask if you can turn it up from inside the car.
     
  10. Longhorn92

    Longhorn92 MS VIN #10103 (40 kWh)

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    I think you were asking the OP, but both of us mentioned that we were able to change the screen charging limit back to 40A (32A in the OP's case). However, sometime down the road, it eventually returns to the 5A limit on a whim (and in the middle of a charging session). They could fix this problem by only checking the charging limit setting when you first plug in. If you start at 40A, it should continue at 40A (unless manually changed on the screen). The car should not be automatically changing the charging limit in the middle of a charging session since you car cannot move locations while charging (which is what the car's GPS seems to be sensing).

    Also, we are seeing 5A/5A, not 5A/32A or 5A/40A.
     
  11. cinergi

    cinergi Active Member

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    Hm, maybe it was Aaron.s. It was at the Natick Mall ... It was charging at 40, we went into the store, checked on its status later and it was charging at 5A ...
     
  12. robaross

    robaross P4550

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    I have never charged anywhere but home, except for supercharging in PSL. Have not tried to unplug and replug without resetting to 32A but my understanding is the memory will keep the last charging level and it must be manually reset. Nice to know I have company.
     
  13. FlasherZ

    FlasherZ Sig Model S + Sig Model X + Model 3 Resv

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    Hit "places" on your Nav app, then select "visited chargers". See if there are several entries for your home with different numbers. (For example, if your home is 4694 Bluebird Ln, you might find entries for 4694, 4686, and 4702...)

    Next time it shows 5A, try increasing it on the charging screen and let us know.

    Good luck!
     

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