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Cold Charging Question

Discussion in 'Model S: Battery & Charging' started by tnt1971, Apr 5, 2016.

  1. tnt1971

    tnt1971 Member

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    I have a 85D that I took delivery of a month ago. Most of my charging is done at work and my round trip commute is about 30 miles. The car seems to use 40-50 miles depending on traffic, temperature, and driving style, which I completely understand. I charge daily to a point where the car sits in my garage at 50% charge overnight, and the garage never drops below 50 degrees. I am having a charging outlet installed this weekend and that will probably only be used on the weekends. I also normally set charging to begin at a time that finishes it right about the time I am leaving.

    Normally my work charge rate is 26mph, at about 212-215 volts and 39-40 amps. This morning was the first moderately cold day I had the car, and it was in the high 20s. I noticed the charging rate was only giving 10mph at 16/40 amps. This has been going on for over an hour. I am assuming it is due to the cold? When it gets really cold, is this the charge rate I can expect or does it heat up at some point and get to the higher rates? I would like to know so I can plan when I need 100 miles of charge.
     
  2. Jeeps17

    Jeeps17 Cath Jockey in a P85

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    If you charge in cold weather, some of the energy used will go to the battery pack warmer. This will be most obvious if you plug in a cold-soaked battery. As the pack warms, this should lessen, and you should notice a progressive increase in the rate of charge.

    Note however, that if you plug in to a low-power outlet (12A-120V for example) in very cold weather, you may see no significant charging at all, even over a period of hours. Your work L2 charger should be fine, year-round.
     
  3. Enadler

    Enadler Member

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    Also when it is cold, assuming you are in a L2 outlet, turn off range mode. If range mode is engaged the pack heater will be disabled and the battery will take longer to warm. In addition, there is no reason you shouldn't leave the pack charged at 90%. No need to limit charge to 50% even if the car will sit for a while.
     
  4. tnt1971

    tnt1971 Member

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    Don't think it is "cold soaked". The car sat in my garage at no less than 50 degrees overnight. When I started driving it this morning, it had the regen restricted at about the 50 mark, but that went away within a mile or two. I drove it 14 miles to work, and started charging right away. Now it is about 2 hours, and it is still only about 10mph at 16amps. The outlet, run, and fuse are rated at 50 amp and I have never had a problem getting to 40amp within a few minutes of charging before today.

    Luckily I don't have any appointments today and if it takes it 5 hours to charge it is no big deal. This will be an issue some days if I need 100 miles of charge and I have to leave early for appointments.
     
  5. tnt1971

    tnt1971 Member

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    Ok. Mystery solved. I just went out to check the range mode and it was off. There was a message on the dash that said "charge cable unlatched" and the port was orange. I took the cable out and reinserted it and now we are up to 24mph and climbing.

    I am surprised it charged at all with the cable not in properly. Also, they should have that message come through on the iphone app.
     
  6. blackscraper

    blackscraper Member

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    I got a different situation. One morning I woke up and check the status of the charging. Whereas it should have stopped already, it was still charging at 16A. I was quite curious what was going on and called Tesla service center. A guy told me there was a voltage surge during the night and the car tried to protect itself thus lowered the charging rate. I was told everything was fine, just unplugged the cable and re-plugged it back in.
     
  7. mikeash

    mikeash Active Member

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    That would do it. If the charge cable is inserted enough to make a good contact but not far enough to lock in place, the car limits itself to 16A. Normally the car wants to shut down charging gracefully before you disconnect anything, and this is a protective measure since it can't force that to happen if the cable isn't locked. It is definitely surprising that it charges at all in this case, but 16A must be low enough that it doesn't hurt anything if it's disconnected suddenly.
     

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