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plugged in at work first time @ 120V hum-dee-dum

Discussion in 'Model S: Battery & Charging' started by scottm, Nov 13, 2014.

  1. scottm

    scottm Active Member

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    #1 scottm, Nov 13, 2014
    Last edited: Nov 13, 2014
    It's -20C today in Canada where I live, and this is when ICE people plug in their block heaters. So I didn't feel too self conscious about using my charge port at work for the first time. All they currently have is 120V outlets... for block heaters. I'm working on getting charger stations put in... next year.

    Anyway, at the app-reported charge rate of 6 km/h, the math says it will take my full 8 hour work day to get back to the same state of charge as when I left home this a.m. So that's fair.

    Of course, my main reason for plugging in was to have stress free use of interior climate warming feature before heading out... not feeling bad about subtracting useful range in doing so. Or will the mobile charger at 120V12A have enough jam to do both? Maybe not enough to maintain at least some charging rate AND do climate control warming when it's -20C outside. I'm about to find out later in the day...

    Also, I imagine keeping a "trickle charge" on all day is a means of keeping the battery pack warmed, hopefully avoiding the dreaded "regen has been disabled" warning I get when having parked outside in the negative temperatures for hours. We'll see. Report to follow.
     
  2. swaltner

    swaltner Member

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    No, the 1.4 kW that you can suck out of a 120V/15A outlet is not near enough to run the climate control.

    However, it's still a good thing to do when it's really cold. You get a couple benefits:

    - As you stated, you recoup almost all the power you consumed on your trip to work, so you have a "full" battery to start the trip home.

    - The charging during the day puts a little heat into the battery, avoiding some of that huge power draw when you first power up after letting a Model S sit for a long period of time in the cold.

    - Even though you won't be able to maintain a full battery charge when you turn on climate control, it's a net positive since you had that 8 hours during the day, which would be enough time to add about 10 kWh to the battery.
     
  3. Kalud

    Kalud Member

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    Keep in mind that its better than nothing, but 120V x 12A = 1.4kW which is much less than either the cabin heater at full speed or the battery heater. I believe they are 3kW each. That being said, arriving with a warm battery (after driving) and charging at 12A on 120V for the full day will probably keep the battery warm enough and even probably keep charging.

    In the other hand, if you plugged the car on 120V after an overnight at -20C then it would only try to heat up the battery without actually charging because there wouldn't be enough energy available from the outlet to get the battery at minimum charging temperature (about 0 degree C).
     
  4. linkster

    linkster Member

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    #4 linkster, Nov 13, 2014
    Last edited: Nov 13, 2014
    Just curious if the receptacle that your plugging into might be a NEMA 5-20 (identified by a sideways "T" neutral). if so, you might consider procuring the appropriate Tesla UMC adapter for a 33% increase up to 16A. (every little bit helps)


    btw, GREAT idea to grab some electrons/range/heat when you can, your S thanks you :wink:
     
  5. cinergi

    cinergi Active Member

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    The cabin heater is far more than 3kW. I'm pretty sure it's at least 6 -- but I don't remember the exact numbers. When I put the heat on full blast while plugged in, I pulled at least 30 amps at 240v. (the battery heater didn't come on) I'll do it again soon to nail it down.
     
  6. randompersonx

    randompersonx Member

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    Curious to hear how it turns out, but I would bet that even if you pull in with a warm battery, at -20C, [email protected] would provide little more than keeping the battery warm, with only a very slight amount of charging.

    That said, even if it's just that, it will still help your return trip since you won't have to heat up the battery and have limited power mode. In effect, this basically means you have the same result as an engine block warmer.

    -20C is COLD, and the battery has a huge surface area to lose heat on.
     
  7. Kalud

    Kalud Member

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    I stand corrected, I remember last winter in the cold (like -20C) with low charge on a "weak" 30A public station, I couldn't get charging AND heating the cabin at the same time, I had to turn heating off (keeping the seats heater)... So this is correct for the cabin, about 240V x 30A = 7.2kW or about that. The battery heater is harder to isolate but is probably about the same.
     
  8. scottm

    scottm Active Member

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    #8 scottm, Nov 13, 2014
    Last edited: Nov 13, 2014
    update

    About 1.75 hours into this... the car is reporting a gain of 10 km range. Pretty much getting that reported 6 km/h rate put into the battery.

    Ambient temps have risen a couple degrees... maybe -18C where the car is sitting.

    Interior temps had dropped from my comfortable cruising choice of +20C to +4.5 in this parked time.

    Experiment time. I decided to give it a shot of interior warming. Within a few minutes it had gained interior heat and reported +5C interior.
    While I was doing that I watched the charge rate. It didn't waiver from "6 km/h" BUT the estimated time to charge began inching up as interior heating was going on.
    I bet the estimated time to charge just would have kept going up unbounded if I left climate on. A slippery slope of going nowhere.

    Obviously needing to use battery power to heat the interior, to deliver the needed power to climate system.
    Which was more than the mobile charger could deliver, because charge to complete time reversed direction and kept going.

    I shut the experiment down.

    So that's confirmed, this circuit cannot provide enough to do both heat and charge.
    It provides "charge" OR "supplement interior heater", not both.

    I will save the climate heating to end of day when I need it the most.

    I will check mid-day with a drive to see if the regen and top end limiters are showing due to cold battery.
    I have 340km range roughly at the moment so top end won't be limiting because of low batt, only if battery is cold.

    I had the same thought about NEMA 5-20 and will look for the tilted pin on the receptacle at lunch.
    I tried dialing up past 12A on the dash... nope, limited by the adapter mated to the mobile charger.
    It's probably worth getting the next adapter up for NEMA 5-20 if the receptacle allows...
    (or just change the resistor in the 5-15 adapter I've already got, and put a switch on it to select the resistor.
    And/or I can always dial down the amps drawn from the dash if I forget to flick the switch. Shh!)


    re: battery surface area. Yes, it's cold here, and it's a huge surface area. (Don't know how snuggly that titanium plate keeps the battery...) but the battery is also a huge mass. So I'm counting on thermal mass to help beat the surface area war. Is there a thermodynamicist in the crowd who can chime in? When it's blowing snow AND -40C here... that will be a different story.. maybe tempted to make an inflatable bladder wind blocker / air dam that seals all around the perimeter of the car to the road, or at least, the side facing the wind :)
     
  9. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    I think the best thing to take away from this is that you are getting a net charge in severe cold, which is a good story that the days of rapid vampire loss making 120V insufficient are gone. :)
     
  10. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Remember that the charge rate reported in km/hr is the average over the entire charging session and won't help you much in seeing effects of turning the climate control off and on.

    You could observe actual rated km in the battery over some time, knowing that the conversion factor is about 180 W-hr/km.

    It never hurts to be plugged in! One word of caution, because a lot of block heaters are only pull 6 Amps or less, the parking lot may be wired with multiple outlets per circuit breaker. If you are pulling the full 12 Amps and a 6 Amp block heater shares your circuit breaker, the circuit breaker could pop. Check the charging with your phone a few times during the day.

    Good luck!
     
  11. scottm

    scottm Active Member

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    I'm the only one on the breaker today, nobody else in my row plugged.

    Mid day udpate:

    Ambient is now about -16C.

    I haven't done my lunch run yet, to check power restriction limiters.

    Here's what I do see.

    Avg charge rate is still reporting 6 km/hr.

    I'm up 26 km range since start, 5 hours ago. So I'm really only taking on 5.2 km/hr. But I did do that experiment with interior climate for a few minutes.

    Here's what else, the estimated time remaining to reach set charge limit is reading 4.75 hours still to go (charge set to 90% which is about 385km for my car).

    Hm.. This a.m. it was projecting about 8 hours to reach goal. 5 hours have passed. And 5 remaining.
    Tells me if it really is achieving 5.2 km/hr throughout, then that's closer to the truth and would occupy the 10 hours.

    Call that optimistic rounding on Tesla's part. 5.2 rounded equals 6.
    Or, some juice is leaving the battery at 0.8 km/hr just sitting there.
    I figure battery heater hasn't had to come on otherwise we wouldn't see these gains that have reached the battery... based on that climate draw experience...

    Anyway, the dynamics of this experiment are about to change because I'm heading out for a hit. I mean drive.
    I want to see if the high or low limiters have appeared, or if the trickle charging has kept those demons away.

    By the way, interior is reading 0C, because it's sunny.
     
  12. InternetDude

    InternetDude Member

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    -20C is cold (small letters), normal winter temp around here. -40C is COLD (all caps) :tongue:

    Please keep us posted, I badly want to buy a Model S, still trying to figure all the details out. Where in Canada are you? Obviously not near the west coast. Hey I've used "block heater" plugs before to charge my plug-in Prius at hotels without chargers, just do it.
     
  13. scottm

    scottm Active Member

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    #13 scottm, Nov 13, 2014
    Last edited: Nov 13, 2014
    I'm in Edmonton. Dude, where you from? If you are a west coaster... Vancouver you have no excuses to avoid model S due to temperature related concerns, if I can make one work where I live!

    Turns out I didnt drive mid day, got too busy.

    So it managed to reach "charge complete" by 4:15 maybe a little sooner but thats when I looked, and saw 381 km range.
    At home I typically get 385 to 387 where the slider is set. Must be the hi octane electrons of 240v 80A circuit there.

    Hopping in the car my dreams were dashed, limiter bars showing top and bottom of scales reduced. But at least my regen wasnt totally disabled.. which I am pretty sure it would have been in these temps if it wasnt trickle charging all day.

    BOTTOM LINE I drove home for free. So yes 120v charge was worth it. If I do this every day, my fuel bill drops in half. Maybe $20 a month instead of $40, ha!
     
  14. InternetDude

    InternetDude Member

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    East of you by more than 2 charges ;-)
     
  15. scottm

    scottm Active Member

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    If youre driving in from that way on hwy16 stop by with your future S and charge up, ive put my HPWC on plugshare.
     
  16. m1ker

    m1ker Member

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    scottm, I think I'm going to do the same with our HPWC, once it's installed in our garage (make it available via plugshare). So if you find yourself in The South end of Calgary needing a charge, just call. For now we have a J1772 30A 240V plug available. Our model S should be here in early March or hopefully sooner.
     
  17. ljwobker

    ljwobker Geek.

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    I'm pretty sure that the "charge rate" reported is the current and voltage going through the charger - NOT the net power being sent to the battery. So regardless of what else is going on with the car's systems, you're going to be putting (in your case) 12A @ 120V =1.4KW through the charger. That juice all flows into the battery, but other systems such as the HVAC, battery heater, etc are drawing on the battery at the same time.

    So... the moral of the story (again, I think with relatively high confidence) that you can see a "charging rate" that is positive and only a function of the input AC power source... while the "time to charge" reflects the NET power going into the battery.

    Maybe someone else can confirm or deny this...
     
  18. scottm

    scottm Active Member

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    I concur

    - - - Updated - - -

    mighty kind o' ya pardner, may just take you up on that... Cowtown is perdy scarce on ev chargin' stations in the south, and that's where my ma lives.

    nuff of that speak.. hehe

    Did you catch the news of Superchargers installing in Canmore right now?
    And Red Deer is queued up to get one at some hotel...
    Getting better all the time!

    What are you charging right now with the 1772?
     
  19. cinergi

    cinergi Active Member

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    I observed ~8kW this morning. 31 amps at 246 volts.
     

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