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anyone here charge ONLY with 120V at home?

Discussion in 'Model S: Battery & Charging' started by f-stop, Sep 14, 2015.

  1. f-stop

    f-stop Member

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    just curious if any Model S owners out there find it practical to charge at home only with 120V outlet?
    if so, what kind of average daily mileage driving do you do with your MS?

    aspiring 70D owner here - I have looked at installing a NEMA 14-50 outlet in the garage, but now I'm thinking since I typically don't drive so many km per day, I could maybe live with just my existing 120V for most around-town driving. Locally around town there are a number of free public J1772 stations and even a couple public HPWCs convenient to places I go, so I figure those would help if needed.

    Lately I tend to drive my wife's SUV most days. I do not have a regular daily commute. There are 2 of us at home, with 2 cars. My own old car (which I'm thinking to trade for a MS) is long, long overdue for replacement and I don't drive it much lately for fear of expensive failure, high maintenance & premium gas costs. Of course, if I bought a MS my driving pattern and daily mileage might change :) - maybe we even end up not driving the SUV much any more.

    If my daily mileage increases enough then I would definitely install a 240V circuit - obviously having a 240V outlet is better/faster, but just wondering if it even makes sense to consider 120V-only to start.
     
  2. beeeerock

    beeeerock Active Member

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    What does 120 volts give you... about 6 km of range per hour? If you're going to be able to consistently charge for long enough each night to replace the distance you drive daily, then it might be workable. But if you can get a 240 volt circuit to your garage and install a HPWC next to your car, you will be much happier. Using offsite chargers to top up will get real old, real fast.

    Yes, you could cook your dinner each night on a single burner Coleman stove in the backyard, but a stove inside with four burners and some real quick heat just makes life easier... ;-)
     
  3. Gizmotoy

    Gizmotoy Active Member

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    I've considered moving to a rental home with only 120V available on multiple occasions. I always calculate my average commute length and then add 30-40% buffer on top of that for inefficient driving and unexpected trips, the amount of time I can guarantee I'll be home each night (sleeping, essentially), and the charge rate at 120V (~3mi/hr) to see if it's feasible. It can be especially attractive if you have higher-rate charging available close by to use in a pinch, but if you forsee yourself using it more than once a month or so I think it'd get really old really fast.

    Best of luck!
     
  4. dsm363

    dsm363 Roadster + Sig Model S

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    120V outlet is possible but makes it tough sometimes. Even if it's only a 30A circuit 240V it would be better than 120V. If a 14-50 isn't too expensive it's the way to go I think. If you went on a long trip and came home wanting to go you the same day a 120V outlet would take over 2 days for a full charge.
     
  5. gavine

    gavine Petrol Head turned EV Enthusiast

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    When you get the Tesla, neither you or your wife will drive the SUV anymore (unless you have to). We put less than 1,000 miles on our SUV since we got our Model S in May of 2014. We put 22K on the Tesla in that same time.
     
  6. AziwA

    AziwA Member

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    Are there any issues as far as the battery longevity is concerned by using a 120v outlet? Could it lead to higher battery degradation?
     
  7. Forty Creek

    Forty Creek Member

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    Winter could be problematic. I know it's milder in BC, but in cold weather you really don't gain much range with 120V.
     
  8. kennybobby

    kennybobby Member

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    You'll get that big ole EV grin...

    Based upon what you have stated it sounds like you definitely could make due with using 120vac for charging.

    You don't have a daily commute requirement and your local trips out are likely fairly short and infrequent. It may be that some of the stores and/or malls that you go to have free charging in the parking lot. For example, the Bridgestreet Mall in my area has free charging at two clipper creek level 2 stations that i have used while shopping.

    If you find you want to drive more, since it's fun and low-cost, then you can always look at putting in a 240vac outlet.
     
  9. f-stop

    f-stop Member

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    thanks all for your replies so far. beeeerock - I *know* your answer is the right one :) just curious to hear what kind of daily mileage 120V-only MS owners can practically live with (assuming such people exist)

    and yes, we cooked on an electric hotplate in our laundry room for a few months when we did a major kitchen reno. Took forever to boil water. I had forgotten about that, we survived but it was pretty annoying at the time!

    other good points, Gizmotoy - I had not thought to factor in some buffer like you say in calculating; also, dsm363 haven't really thought about longer trips yet but good point...
     
  10. seclinton

    seclinton Member

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    Ohh my god. We have been hitting the SC pretty heavy lately and i noticed my 90% charge dropping lower, maybe also due to aggressive driving, so I plugged in last night with the UMC 120V at a whopping 12A and was getting ~3mile/hr. Overnight went from 25 miles to 72. Chose to use the slow charger as an experiment vs. my Level 2 @ 30A.

    Well that stopped. I just don't want to charge my car for 54 straight hours to 90% or be in constant plugin mode, which is what I'd do with the 120V UMC.

    So back to my Sieman's Versicharge cranking out ~6kW (30A @ 220V) to fill er up from the same state in about 6-8 hours.

    It's good in a pinch, but not practical for such a high capacity battery (85kW)

    - - - Updated - - -

    Ohh and charging slower at Level 1 is more efficient than level 2 is more efficient than SC.

    Put simply, a quiet, slow charge allows those huge Lithium ions to swim deeper into the carbon matrix (anode) during charging, thus avoiding a traffic jam and literally "clogging" the "pores" in the anode. Not really worth reading about coulombic and faradaic efficiency, but slower charging is better for longer life and a more efficient charge (i.e. slightly higher full charge estimated range).

    No long term damage from Level 1 or Level 2 charging. Period

    qualifier: I am 15+ years in batteries, development and manufacturing, and yes, I developed cylindrical cells. And I'm still in consumer small format batteries.
     
  11. KidDoc

    KidDoc Member

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    I lived in a rental for the last 7 months so had access to a 30 amp circuit if I unplugged my dryer or a regular ole 3-4 MPH 12 A. My normal daily drive is 20-30 miles. It worked fine. If I started to fall behind on the daily charge I would just unplug the dryer overnight and that would give me 18-19 miles per hour.

    Honestly in your situation I bet it would be fine. Just understand that if you take a road trip and get the battery a bit low it will take days to recover the charge. Also note that I live in Texas so didn't have to deal with really cold temperatures. In the winter you may be lucky to eek out 1-2 miles per hour plugged into 12 A with the battery heater on.
     
  12. Cosmacelf

    Cosmacelf Active Member

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    If you do charge at 120V, try to find a plug that is on a 20A breaker so you can use Tesla's NEMA 5-20 adapter for 42% faster charging. You might have to swap out the outlet itself to a 20A outlet, but easy to do.

    120V charging is inefficient since a lot of the power isn't going into the battery, it is going towards keeping the computer awake and the cooling system running.

    Also, if you have 240V charging, you can charge during off peak hours where electricity is cheaper, if that is available in your area.

    While I have charged with 120V in the past, and will do so in the future for occasional use, I personally wouldn't rely on it for full time use. Over a long period of time, you will have times you wished you were going to have a full "tank" for the next day, and you won't be able to get there...
     
  13. f-stop

    f-stop Member

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    yes, generally it's very mild here in Vancouver, compared to Ontario or the rest of Canada - winter temps might hover a few degrees above/below freezing in the city, though rarely much colder than that, certainly not for extended periods.
    OTOH my garage is uninsulated & detached from house so I suppose the car would be generally cold parked in winter. Any idea roughly how much less charge/hour to expect assuming near freezing temps at worst?
     
  14. vitaliy

    vitaliy Member

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    I have 0 knowledge in anything electricity related, but isn't it possible to create an adapter for two 120V outlets, so instead of 4miles/hour it will be 8miles/hour?
     
  15. Max*

    Max* Autopilot != Autonomous

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    I was on 120V for two months. It wasn't bad, but I constantly had to think about how much charge I have. My commute was 20 miles round trip. It worked.

    But when we took road trips, I couldn't come home with a low SOC otherwise I couldn't run errands the next day.

    I have a nema 14-50 now. It simplifies life, but 120V charging with low mileage is definitely doable in the summer (can't speak for winter)
     
  16. TexasEV

    TexasEV Active Member

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    Sorry, battery expert, but charging a Model S slower at 120V is LESS efficient than 240V charging. You can search for the dozens of posts explaining this. There is more to efficiency than what happens inside the cell. The cars should be charged at 40-80A as designed.
     
  17. Max*

    Max* Autopilot != Autonomous

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    Can you show me the design doc, please?
     
  18. Theshadows

    Theshadows Active Member

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    Most outdoor outlets are on a 20a circuit. If the circuit was installed correctly and they put in 20a outlets the adapter from Tesla would be well worth it.

    In a 20a outlet the top two holes look like this. + | vs a 15 amp which looks like this | |
     
  19. MorrisonHiker

    MorrisonHiker Beta Tester

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    #19 MorrisonHiker, Sep 14, 2015
    Last edited by a moderator: Mar 13, 2016
    Such a device does exist but I don't think many here would recommend using it. You have two be sure that the two outlets aren't on the same circuit.

    110-120 and 220-240 Voltage Converters & Accessories

     
  20. Cosmacelf

    Cosmacelf Active Member

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    There are two issues with combining 120V circuits. First, you must find two circuits that are on different legs of the electrical panel. Second neither plug or circuit can be protected by a GFI outlet, and most garage and laundry outlets are GFI protected. So while possible (I've done it in the past), you can't always do it in any random house or location. Also, now you are stringing two electrical cords all over the place, increasing trip hazard considerably.
     

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