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Should I charge, or shouldn't I charge, when...

Discussion in 'Model S: Battery & Charging' started by brianstorms, Sep 17, 2013.

  1. brianstorms

    brianstorms Member

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    #1 brianstorms, Sep 17, 2013
    Last edited: Apr 11, 2014
    ...

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  2. dhrivnak

    dhrivnak Active Member

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    Tesla's advice, and mine is to leave the car plugged in at night and whenever possible. You have an 8 year unlimited mileage battery, do not sweat the small stuff. I have been following Tesla's advice on my roadster for the past 29 months and have not seen any battery degradation.
     
  3. brianman

    brianman Burrito Founder

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    90%

    - - - Updated - - -

    I take a shower every day whether I need it or not.
     
  4. caddieo

    caddieo Member

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    Correct me if I am wrong, but my understanding (based on1.33.61) of the advantage of keeping the car hooked up is that the wall power (instead of the main battery) provides the juice needed to keep the basic electronic functions going. Absent this, you have a vampire power drain that may affect the 12 volt battery adversely.
     
  5. Doug_G

    Doug_G Lead Moderator

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    Just plug in. Put the slider where you think best.
     
  6. GlennAlanBerry

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    I would say you are worrying too much about it. I think (from what I have read from Tesla) that as long as you don't go down to zero or up to 100% on a regular basis, you will not hurt the battery longevity. The pack takes care of itself from a temperature perspective.
     
  7. rdrcrmatt

    rdrcrmatt Member

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    I go 90% to 8-10% almost daily. uh oh.
     
  8. jerry33

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

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    I don't much worry about it. I set the start time so that it's done shortly before I leave (most days), and put the slider so that range is over 200, and call it done.
     
  9. earlyretirement

    earlyretirement Model X 90D

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    #9 earlyretirement, Sep 17, 2013
    Last edited: Sep 17, 2013
    I wondered the same thing as Brian. Actually in version 5.0 you only lose about 1 mile over night with vampire loss. I know that Tesla says to always plug it in but if I just charged and didn't really use it too much that day I won't always charge it that night. Also, I didn't charge a few nights to see about vampire loss rates.

    Brian, like you I have the dedicated meter from SDGE so the nice thing is you can experiment with this sort of thing. Since our meters started out from 0.00 it's easy to track. Just for kicks, I've been noting exactly how many miles I charge each night then log it on a spreadsheet in the morning at what the kWh shows on the meter. I'll keep some meaningful period of at least a month then I'll post a Google Doc with the spreadsheet for anyone interested.

    I would have thought that the green led light on the HPWC would at least draw some electricity but I've never noticed the meter have changed at all from the last reading. So it must not be anything noticeable at all which is great.

    For example. 3 random samples of charging below. (For frame of reference I have a HPWC and dual chargers at 80 Amps and I set to charge at 1:30 AM).

    168 rated miles. It used 66 kWh. I have TOU EV super off peak charging rates with SDGE in San Diego (https://www.sdge.com/sites/default/files/regulatory/schedule_ev-tou_090113.pdf) which comes out to about $10.56 to charge the 168 miles.

    155 rated miles used 49 kWh for an effective price of $7.84

    142 rated miles used 45 kWh for an effective cost of $7.20.

    Also, for further reference, on Tesla's website Tesla Charging | Tesla Motors it showed 170 miles as only using about 55.9 kWh with the HPWC and dual chargers. And explained by other Model S owners, you will use more energy for the car and the cable while charging so it will always be higher than what Tesla's website shows.

    Estimates above aren't exact and just estimates. I'll need to see what SDGE charges with taxes and usage fees and possible generation fees. I didn't get my bill yet since I got the dedicated EV meter so I'll see how it affects the rates.

    Hope this helps.
     
  10. efusco

    efusco Moderator - Model S & X forums

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    Technically, no reason to plug it in in the circumstances you describe. But it's a good habit to form.
     
  11. Crispix

    Crispix Member

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    I don't understand this part. You own a brand new Model S!
     
  12. earlyretirement

    earlyretirement Model X 90D

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    Ha, ha. Yeah, I wish I had that problem. Previously I hated driving and tried to avoid it but after getting the Model S I'm driving more than ever. But I know owners that work from home, live across the street from their office, stuck in meetings all day or have really heavy load days. On these days is when they don't use it too much. To be honest, I haven't had too many of these types of days. I always invent excuses to go out and drive the car.

    Also, I love the expression on friend's faces when they test drive the car. I took a Lotus owner out today and he was blown away by the performance. His exact words were, "The torque and acceleration is intoxicating. "

    Also, been meeting up purposely further away from the house for lunches with friends. The car is amazing.
     
  13. Lump

    Lump Active Member

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    During the week the car is driven about 25 miles a day, so I don't see the need to plug in every night since I doubt the low threshold is met & charging wouldn't be done anyways, so I typically charge to around 200 then when its down to around 125 I plug it in, except if its a weekend or know of the need for more miles for the next day (v5 so no vampire loss).
     
  14. kendallpb

    kendallpb Model S: P 8061

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    Well, at that rate, it will take a while to get from 237 down to 175, won't it. ;-) Up to 10-12 days, depending on software version and whether you drive 2, 3, 4, or 5 miles a day. If you really want to top off at 175, then you can either wait a week+ until you hit at level, or else go and drive 60ish miles. Up to you; it sounds like you get too much TMC time and not enough CAR time...so maybe you should take the drive? ;-)

    As Evan says, it's good to get into the habit of plugging in. But don't obsess so much; you're putting me to shame, and I'm pretty obsessive. :cool:
     
  15. brianman

    brianman Burrito Founder

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    1. Approach car with fob
    2. Open passenger door
    3. Open passenger window
    4. Close passenger door
    5. Tap 17" screen
    6. Set driver climate to LO
    7. Set passenger climate to HI
    8. Leave vehicle alone for 30min or so
    9. Check on vehicle, if rated miles remaining is > 175 return to step 5
     
  16. Al Sherman

    Al Sherman It's about THIS car.

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    I "essentially" asked the same question back in May when 4.5 came out with the slider. It lead to a very long thread with lots of opinions from smart people. HERE. You may find it useful and/or interesting.
    FWIW, based on all the opinions I've read; I chose 65% (yields about 160 miles rated on the 85) and I plug the car in whenever I pull it into the garage. I average less than 800 miles a month, and most days I drive less than 20 miles.
     
  17. sublimaze1

    sublimaze1 8Dec2012 / Leeroy Jenkins

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    No need for uh oh. Diana drives BadA** from Mckinney to Fort Worth twice or three times a week. She racks up just shy of 145 miles on her route. We charge to about 85%, and she cannot seem to keep the car below 85 miles per hour. So when she pulls up to the charger at home, she is at about 25 rated left. So her use seems to be just about what yours is. We have ~16K on the odo, had the car since December '12, and have not noticed a bit of degradation yet. I have full charged about 12 times (trips to Houston, Austin, etc.).

    I agree that some of this is mental mas******ion, but I have learned that, if I forget to plug in at night, or I try to guess how much I will need for the next few days, I will underestimate and have range anxiety.

    I plug in every night I am home.
     
  18. David_Cary

    David_Cary Member

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    I have a Leaf and it is out there not plugged in. Probably 50% charge.

    You could argue that plugging it in every night puts unnecessary wear on the plug and that doesn't have an 8 year warranty.

    While it may not matter that much, most everyone agrees that keeping the battery SOC as low as possible is best for battery life. People like to think the TMS on a Tesla's battery prevents any and all damage but it doesn't cool below 105 degrees (my understanding) and there is quite a bit of damage at long term at 104 degrees and 100% SOC. And that is less at 90% SOC and less at 50% SOC and less at 30% SOC...

    While there is an unlimited 8 year warranty, there is no clear language that capacity degradation is covered (and it isn't covered by anyone else unless specifically spelled out). So you could be at 6 years with 70% capacity going to sell your car. Certainly someone who babied the battery and has 85% at 6 years will command a higher price. The biggest determination of resale will be range/battery capacity.

    It isn't that different from doing oil changes on a regular basis...

    Elon's recommendations have their merit but that doesn't mean I would listen to them.
     
  19. djp

    djp Roadster 2.0 VIN939

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    Brianstorms, I went through the same thought process as you a couple of years ago when I bought my Roadster. For the first couple of months I plugged in every night and charged in Standard mode. Then I realized I was only using a few miles a day for my commute and it was silly to hold the battery at full standard charge, especially since high SOC speeds degradation that isn't covered by the warranty. At $40K to replace the battery I'd like mine to last as long as possible.

    I then started plugging in every night, resetting the charge level to Storage mode, and manually topping up to 50% whenever I needed it. After a couple of weeks doing this I realized the car never charged on its own and I was plugging and unplugging needlessly.

    Now I plug in about once a week to top up to 50%, or I'll plug in at night for a Standard charge if I need to do a longer trip the next day. I've seen no negative impact - in fact it charges to the same level it did two years ago when I bought the car.

    Tesla recommends you plug in every night to avoid a situation where you completely forget about the car for a few months and the vampire drain runs the battery down to a point where the car won't wake up. This is less of a risk with the improved sleep mode in the 5.0 firmware.
     
  20. wycolo

    wycolo Active Member

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    > Tesla recommends you plug in every night to avoid a situation where you completely forget about the car for a few months and the vampire drain runs the battery down to a point where the car won't wake up. [djp]

    Car . . what car . . . who . . me?? :eek:
    --
     

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