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Charging 220v or 110

Discussion in 'Model 3' started by White Knight, Sep 22, 2019.

  1. White Knight

    White Knight Member

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    I traveled about 30 to 40 miles a day except for Saturday. Saturday probably 100 miles. Questions is what is the best alternative to charge my car. Charge my car Monday to Saturday to 90% using 110v and crank it up 100% on Sunday using the 220v or charge 90% up 3 times a week using the 220 volt?
     
  2. acarney

    acarney Member

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    Are you saying what is better for your battery or what is better for your lifestyle?

    I don’t believe there is any issue with battery health with charging at 240v. The max you’ll do on the SR+ is 32 amp, so approx 7.6kW. As far as I know that’s entirely safe for the longevity of the battery. Keeping the charge somewhere between 70-80% is going to do a lot more for your battery health then ~1.4kW (120 volt 12amps) charging.

    On a SR+ 70% should get you ~170 mi. Even with aggressive city street driving or cold weather you should be able to get 90 to 100 miles out of that.

    So, probably get a 50 amp NEMA 14-50 installed and just use the standard mobile charger that comes with the car and plug it in every night with your charge limit set to approx 70%. Maybe bump it to 80 or 85% if there is snow on the ground or you’re in sub freezing temperatures. If you really wanted you could just charge every other or third day, but the vast majority of people just plug in every night.

    Edit: To compare, if you’re worried about frequent supercharging events causing Tesla to throttle battery charging speed, that’s fairly rare AND when they do throttle it, it’s usually still 50-60kW or more. Max supercharging rate on SR+ is 100kW. So your “fast” home charging is less than 10% as fast as Tesla allows the battery to charge, and still ~15% as fast as Tesla allows a throttled battery to charge!
     
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  3. Matt L

    Matt L Member

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    For that style driving, 110v plug it in every night and charge it to 90%.
     
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  4. ecarfan

    ecarfan Well-Known Member

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    If you have 220V charging available to you and it is convenient, then I recommend using it. Why not? There is no downside that I can see, based on your post.
     
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  5. novox77

    novox77 1.21 Gigawatts

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    charging at 120V is less efficient. You'll lose a lot to waste. If you have the 240V available, use it. Given the pack size, it's still a trickle. No worries about battery longevity. Charge to 90% max unless you need the full range of the car on your next drive.
     
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  6. Saghost

    Saghost Well-Known Member

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    Do you have both 120V and 240V convenient to where you normally park? (110V and 220V are obsolete in the US. I very much doubt you actually have either of those.)

    If you do, why would you ever use 120V? Less efficient/more overhead, riskier outlets, and no upside I can see.

    If not, where would you be doing the 240V charging?
     
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  7. ewoodrick

    ewoodrick Active Member

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    Set at 90% and charge at 240V
     
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  8. Matt L

    Matt L Member

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    How much charging will it take for the inefficiency to cost more than the cost of the 240v install?
     
  9. RandomX

    RandomX Member

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    #9 RandomX, Sep 22, 2019
    Last edited: Sep 22, 2019
    Plug in using the 240 every night if you can. A plugged in Tesla is a happy Tesla. Then systems can use wall power instead of flexing on your battery during the Plugged In Time.
    For battery health having your battery spend most of its existence charged at or near 50% is best.

    So, if you use about 20% capacity on any weekday. Charge to 70 or even 60 those days. That means most of the time your battery will be between the 40%-60% range. That's perfect for battery health. If you use 30-40% battery during a normal day then I would charge a bit higher to 70%. Which means your battery will spend most most of the time between 30 and 70%.

    Still, I would bet that most of us are guilty of over charging our batteries. I am too but I always think to myself... I might have to drive somewhere, far and unexpectedly. But realistically how often does that happen.
    However...
    If you do typically unexpectedly travel I recommend gauging that in and charging extra for that.

    Going below 20% can be very hard on the battery. Worse than being charged to over 80%.
    The big reason for that is there are controls on how much charge a full battery or nearly full battery can take. Overcharging a full battery or charging it too quickly is bad for it . Also discharging a low battery aggressively is bad for it .... and there are less of controls on how aggressivly you can discharge a low battery. And by discharge I mean stomping on it and taking off.
    Basically they want you to have full power when you stomp on the accelerator pedal at all battery ranges.

    RandomX
     
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  10. novox77

    novox77 1.21 Gigawatts

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    how many variables to you want to consider when making that comparison? :rolleyes:
     
  11. M3BlueGeorgia

    M3BlueGeorgia Member

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    The issue is what is your normal worst case scenario, not your average?

    By all means start off using 120v/15A. Its slow, but it works.
    You are in OK, so intensely frigid conditions aren't a factor here.

    But if you find yourself charging occasionally for more than (say) 10 hours overnight, that'll be time to upgrade to 240v charging.
    Having 240v is really great, but there's a cost with running a 6 gauge wire from your breaker box. You have to make that call.

    It isn't really so much about efficiency, more about convenience and functionality.

    Another factor is whether you get a time-of-use electric plan. If you do, it might have a narrow window for really cheap power (mine's from midnight to 6am), so you'll need faster charging to consistently stay inside that window.
     
  12. fajitamondays

    fajitamondays Member

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    For that "wake up in the morning to a full tank" feel, 240v on a 50 amp or better circuit all day every day.

    120v is painfully slow, and all it takes it one unplanned long drive to put you into a bit of a deficit where you need L2 or a Supercharger to reset back to a comfortable place where you can then top off with 120v to 80-90% state of charge.
     
  13. White Knight

    White Knight Member

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    I have a 110 plug and a dryer outlet or use the 220v (30 amp breaker in my patio). I have options. I would think using a 220v system to charge my white knight, i would be paying less $$$ on my electricity bill especially in hawaii. Is this true?
     
  14. novox77

    novox77 1.21 Gigawatts

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    the ineffiency of charging at 120V vs 240V is mainly due to fixed losses associated with the charging process, not the circuits themselves. Because 120V charging takes much longer, the car is kept awake longer, and as evidenced by the enormous threads on vampire drain, an awake vehicle drains the battery much faster than an asleep one. Charging at any speed means that same awake draining force is being applied. The faster you complete your charge, the less loss from "awake car" there is. In cold weather, 120V charging sometimes manages to only break even with the increased inefficiency due to temps. This was a bigger problem with S and X due to their dedicated resistance heater for the battery.

    On the other end of the spectrum, if you're on a 240V circuit and charging at high amps, you increase resistance in the wire, which is loss via heat. You can see the effect of this by lowering your charging amperage and watch your voltage go up a bit. A thicker gauge wire can minimize this, but the wire will cost more $$.
     
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  15. derotam

    derotam Member

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    This is a more appropriate answer than just saying "charging at 120V is less efficient. You'll lose a lot to waste."

    Sometimes oversimplifying something can be just as bad as going down the rabbit hole. :)
     
  16. lolder

    lolder Member

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    It'll be cheaper to charge at the 220 v dryer particularly at Hawaii electric prices.
     
  17. mmiketa

    mmiketa Member

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    What do you mean 120V and 240 are obsolete in the US? That's the standard residential voltage. Every commercial building you go into and you see a receptacle it's most likely a 20A, 120V receptacle.
     
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  18. 5_+JqckQttqck

    5_+JqckQttqck Active Member

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    Get a 14-50 installed to future proof. You may come home late from a road trip and have to work the next day. Instead of dropping into a SuC. You just plug in and go to bed. It will make life easier when you do need that extra bit of top up to ensure 70/80/90% in the morning.

    Or when you're just dropping home for a hour or two. Getting 47km (30mi) per hour is way better than 7km(5mi) per hour.
     
  19. Runt8

    Runt8 Active Member

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    He said 110 and 220 are obsolete, not 120 and 240. They aren't the same thing despite many people getting them confused.
     
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  20. Saghost

    Saghost Well-Known Member

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    Read the text, then post. 110V and 220V were real standards in the US, the better part of a century ago. These days, it's all 120V and 240V instead - but for some reason a lot of folks still call it 110V and 220V.
     
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