TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

120V Charging in the Cold

Discussion in 'Model S: Battery & Charging' started by Doug_G, Dec 28, 2012.

  1. Doug_G

    Doug_G Lead Moderator

    Joined:
    Apr 2, 2010
    Messages:
    15,852
    Location:
    Ottawa, Canada
    My garage is around freezing right now. I've got the car on 120V charging and the console says it's doing 2 km per hour, i.e. about 1 mile per hour. I'm assuming it's putting a fair bit of power into heating the pack. What are people in warmer climes seeing?

    (I'm plugged into 120V because it helps keep the pack warm. Tomorrow morning I'll top it off at 240V 70A before I head off on a road trip. Hopefully this will no longer be necessary once we get that iPhone app.)
     
  2. Jason S

    Jason S Model S Sig Perf (P85)

    Joined:
    Apr 20, 2012
    Messages:
    1,350
    Location:
    Rocklin, CA
    3 miles per hr at 12A is the norm here in California. Tho I think it is about 40F in the garage right now.
     
  3. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
    I would be interested to know if the power that goes towards keeping battery pack temp up comes from the barttery or straight from the wall (bypassing battery)? The battery can't charge AND discharge at the same time right? So if heating power comes from the battery it self then current draw from the plug (charging) would be intermittent with periods of heating between? If heating energy comes dorectly from the outlet then draw would be continous, with some going to heating and some (obviously just a little) to charging.
    I wonder which alternative is better For battery wear? If heating comes from pack it would probably be more efficient, since the discharge it self creates some heat, but it would also mean more charge/discharge cycles over time (without adding miles to the car) albeit without probably ever reaching lower SOCs.
     
  4. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

    Joined:
    Mar 8, 2012
    Messages:
    12,756
    Location:
    Texas
    This doesn't sound correct. If it were true then you couldn't use your cellphone when it's plugged in to charge.
     
  5. GDH

    GDH Banned

    Joined:
    Dec 5, 2012
    Messages:
    1,009
    Location:
    Portland, OR
    Would it help to put a safe space heater in the garage?
     
  6. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
    You could if the phone runs off the grid while plugged in, which I believe it does, keeping the battery "out of the loop" and still charging. We're talking something like 5-10W here so no big issue.

    So basically my question is can the power from the wall plug go anywhere else besides into the battery of the Model S? Can it go directly to battery heating? Can it power the HVAC systems? I hope so...
     
  7. Doug_G

    Doug_G Lead Moderator

    Joined:
    Apr 2, 2010
    Messages:
    15,852
    Location:
    Ottawa, Canada
    Okay, I just had a look and according to the touchscreen it's -14C in the garage. Well below freezing...
     
  8. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    Most of the non-traction systems in the car are 12V based, and the AC power does not directly power them from the chargers. There is a DC-to-DC converter that ensures that the 12V system is kept up (aside from the recent issues with that system). It is my belief, based on observation of how the car handles its charge, "vampire load", etc., is that AC power applied to the car cannot maintain a fully-powered path to power those systems directly. Perhaps there is the capability, but I definitely know this is not how the car currently handles it. Leaving your AC mains power plugged in and turning on your HVAC will drain your battery until "top-off" occurs for the main battery pack.
     
  9. EcoHeliGuy

    EcoHeliGuy Member

    Joined:
    Dec 2, 2012
    Messages:
    545
    Location:
    Canada
    #9 EcoHeliGuy, Dec 29, 2012
    Last edited: Dec 29, 2012
    I'll try to keep this basic. (Some times I have trouble with that :confused:)

    Whether its ICE cars, cell phones, AA's or your electric tooth brush, they all charge basically the same way.
    I'll use cars and easy numbers (not exact)

    When a 12v battery is charged it really reads 13v, and when dead it will have 10-11volts. 12 is the average so we call them 12 volt batteries.

    If you want to charge a battery, you most apply a higher voltage to it in order to get current to flow in the proper direction. Also greater the voltage difference, the greater the current flows. This is why battery charge rates lower as the battery become closer to full charge.

    So charging systems will run at 14 volts to charge the battery, this is slightly higher but not too great to damage the cells, So current flows into the battery. There are other systems down stream of the battery, head lights and fuel pumps will also draw current. They aren't discharging the battery, because the charging system is able to offer up more current then the battery can handle. Picture the system as being tied to a Tee, some current goes to the battery, some goes to other loads. In the case of a cell phone the wall charger has a higher output then the phone uses, so while you chat the extra current ends up in the battery.


    So in the Model S, when you plug into the wall, some current goes to the battery pack, and some goes to other systems. It doesn't matter where this split happens, at the battery or up stream at the plug. In the OP'S case 2km's worth of energy was being added to the battery pack an hour, This was the available after all the other systems used what was needed. And was probably only for a few minutes, once less energy was needed for other systems (heating), the battery would have access to more.

    This is why they use the term current draw, everything draws from the source, once the demand stops, the current stops. And that's why you set Amperage draw from the touch screen, your telling the car what to "ask" for.

    Hope this helps
     
  10. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
    EcoHeliGuy: thanks, very helpful! Very well explained and quite obvious now that you've said it.
     
  11. efusco

    efusco Moderator - Model S & X forums

    Joined:
    Mar 29, 2009
    Messages:
    4,590
    Location:
    Nixa, Missouri, United States
    That's what I do...keeps the garage around 40-45F even in the coldest weather outside--much more comfortable to get in our cars thta way and the car stays happier. Did this (as well as an engine block heater) on my Prius and was able to still get around 55-60mpg even in winter.
     
  12. dsm363

    dsm363 Roadster + Sig Model S

    Joined:
    May 17, 2009
    Messages:
    18,235
    Location:
    Las Vegas, NV
    With the future ability to preheat your Model S cabin to whatever temperature you want, would this still be necessary?
     
  13. Johan

    Johan Took a TSLA bear test. Came back negative.

    Joined:
    Feb 9, 2012
    Messages:
    6,890
    Location:
    Drammen, Norway
    Warm garages in places with long winters and temp below freezing tend to increase rusting and related wear, since the car goes through a lot of freeze-thaw cycles. Less of a problem with Au body, but still there are things that can rust on a Model S. Cold garages are better in this respect. Moderate heating of the cabin (including preheating) doesn't necessarily bring the entire car's temp up above freezing if it's cold out, or in a cold garage.
     
  14. efusco

    efusco Moderator - Model S & X forums

    Joined:
    Mar 29, 2009
    Messages:
    4,590
    Location:
    Nixa, Missouri, United States
    Maybe, I'm still interested in keeping the battery warm...and my wife's car doesn't have that option and she likes getting in a nice warm vehicle too.

    FWIW, we only use that space heater when it's forecasted to be below freezing outside.

    - - - Updated - - -

    I did bring my UMC to work this morning and plugged in the Tesla on the 120V in the parking garage. The estimated time said 4 hours to charge (about 14 mile drive to work) and I won't leave work for at least 4-5 hours after that's done. Will the 120 still keep the battery pack warm even after it hits full charge (standard range)?
     
  15. dsm363

    dsm363 Roadster + Sig Model S

    Joined:
    May 17, 2009
    Messages:
    18,235
    Location:
    Las Vegas, NV
    It sounds like heating your cabin with the iPhone may warm the battery but don't have confirmation on that.
     
  16. Norbert

    Norbert TSLA will win

    Joined:
    Oct 12, 2009
    Messages:
    4,424
    Location:
    San Francisco, CA
    So, Doug, if you are also drawing something like 12A, then we should be able to assume that about half of it is used for battery management (and running the computers until sleep mode becomes active).

    I'd think it is a good thing to keep it plugged it, probably even in the summer, to keep the remaining appliance draw from cycling the battery additionally. (That is, the battery level would go down further than otherwise, and then, when charging, up again.)
     
  17. FlasherZ

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

    Joined:
    Jun 21, 2012
    Messages:
    7,019
    The warning in 1.17.31 says precisely that - running the climate control activates the battery heating circuits too...
     
  18. Doug_G

    Doug_G Lead Moderator

    Joined:
    Apr 2, 2010
    Messages:
    15,852
    Location:
    Ottawa, Canada
    No. Roadster does (since a firmware update from over a year ago). Model S currently does not. Would be very nice if it did.
     
  19. mknox

    mknox Well-Known Member

    Joined:
    Aug 7, 2012
    Messages:
    8,566
    Location:
    Toronto, ON
    I hear this a lot, but my experiences have been the opposite. My mother still drives her 1987 Chrysler LeBaron (yes, that's a 25 year old K-car!) and parks it in her heated condo lot. There is no rust on the car at all, and it was never even rustproofed or undercoated. My own cars parked in my garage (which is usually above freezing based on the snow melt and water on the floor) have all held up very well rust-wise.
     
  20. stevezzzz

    stevezzzz R;SigS;P85D;SigX

    Joined:
    Nov 13, 2009
    Messages:
    6,062
    Location:
    Colorado

    I know European pricing is set to be significantly higher than here in the US, but still, it's a hell of a deal if the body panels on cars shipped over there will be Au instead of Al. :wink::biggrin:

    Should be a big help with corrosion problems, too.

    [...don't sweat it, Johan, I knew what you meant: just pulling your leg a little...]
     

Share This Page