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Ideal Settings for "End Time" Charging before trips..?!

Discussion in 'Model S: Battery & Charging' started by arijaycomet, Jan 1, 2015.

  1. arijaycomet

    arijaycomet Member

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    #1 arijaycomet, Jan 1, 2015
    Last edited: Jan 1, 2015
    We (my wife/I) are 24-months into a 39-month lease on a 2012 Nissan Leaf. We just had our 2-year check-up for the battery and our local Nissan dealer said not only did it test out perfect (5-stars on the print-out they supplied), but that he said we are the only car he has seen locally (Cleveland, Ohio) with similar age/mileage that has proven such a perfect battery score. He was quite curious how we managed this! Even though the vehicle is leased, we take pride in our tangible items, and have done our best to maintain ideal conditions for the battery & charging protocols.

    Due to the limited range of the small 24-kWh battery, we have always charged up to 100%, though we've typically never let the car get below 20% SOC. However, to keep the car from sitting at a full SOC for a long period of time we have always utilized the awesome "End Timer" feature built into the car. We would set it to end charging 15-20 minutes prior to our normal week-day departure for work (the wife/I commute together). Even on the weekends we would leave the end-time the same time, so 2-days a week it would often sit for 3-4 hours at 100% SOC. Perhaps having a heated garage has also helped the battery survive so well.

    But TO THE POINT.... there is obviously not "end charger" option for the Tesla. Our recently acquired 2014 Model S 85 RWD will probably become our more common trip car (so we're going to set the Nissan to the optional 80% max SOC to preserve that battery). My issue/concern/question comes from how I should charge the Tesla. I'm not a n00b, so I am fully aware that I can set the car from 50-100% and I'll have to figure out what the best option there might be-- and just deal with it from there. But what about long trips?

    Tomorrow is our first distance-trip in the car (we're going ~140 miles away -- we will use Tesla HPWC available at a parking garage for a few hours to refill before return trip). I'm plugged in now to be ready for tomorrow, and due to the distance and other running around we may do I'm going to set to 100% SOC. However, ideally I'd like the charging to end at 8:30 AM (our rough departure time). What I did this time around was-- (1) plugged the charger in, saw how long it estimated it would take to charge (3hr 25min) then (2) did some math and added a 30-minute (rounding up to 4-hours as a safety number to make sure it would be done in time).. then (3) set it to STOP charging for right now... and finally (4) set it to start charging 4-hours prior our departure time (around 4:30 AM).

    That seems the only way to achieve the goal of having the car not spend too long at 100% SOC.

    Am I correct that, at the current moment, this is both ideal, and the only way to achieve this goal? What do the rest of you do? Do you simply plug in the night before a trip at bed time, set it to 100% SOC, and just deal with the fact it will sit there for potentially 5-6 hours at 100%? Or are there other tricks I'm not aware of? Also, it appears you can set charge limits from the phone but not a delayed start time, that is a bummer!

    TIA for any pointers ... I'm not new to EVs, but I'm definitely still getting acquainted with the differences/nuances of the Tesla vs our 20,000+ miles on our Nissan Leaf. Looking forward to my seat-time tomorrow!

    PS: Simply for reference... my charger is a 40A Leviton EVB40-PST that charges ~30/mph (238v 40a). We upgraded from an older 30A unit (details on that HERE)
     
  2. linkster

    linkster Member

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    This is just my opinion and others will rightfully disagree. 23 mos/42,500 miles here and have only range charged twice. If I had a 140-mile trip I would just charge to 90%. I try to keep the S at 50% for most hours of the day. I try to time the charge session to end just before departing if I go to 90+%. Elon stated on twitter to an S85 owner to charge to 80% for a commute that required 50% depletion (80-30%). Hope this helps and enjoy your new EV!
     
  3. arijaycomet

    arijaycomet Member

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    That is interesting. We have some long trips planned using superchargers, many which are only 100-150 miles apart. I was thinking I might be better off charging to only 80% roughly and then supercharging each chance I could. But that calls for argument which is worse higher SOC vs frequent rapid charging LOL

    Btw, I should clarify. My trip is 140-miles in each direction for a total of 280 miles (freeway) plus some incidental miles around town (30-40 Max). So 300+ total miles expected entire day. There is access to Tesla HPWC and a public 30A station but no supercharger this trip. So for the 8-hours we will be down there I'll be 240v charging and want to make sure I have enough juice to get home. Hence starting at 100% as safety net.

    Thanks for awesome feedback!
     
  4. pgiralt

    pgiralt Active Member

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    This is one of the reasons I like having twin chargers and HPWC. When I'm going to go on a trip, I will 90% charge as usual overnight. It only takes about 40 minutes to do the other 10%, although what I usually do is set it to 100% 2 hours before I plan on leaving because it can sometimes take an hour to balance the pack. If I have to stop it before it's balanced, it's not a big deal, but I just take the opportunity whenever I need to range charge to balance.

    Even if I'm using superchargers for a long road trip (e.g. driving from NC to Miami which requires 6 SC stops), I will usually range charge anyway just to reduce the amount of time needed on that first supercharger stop.
     
  5. Zarwin

    Zarwin Member

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    I charge to 90% overnight and then simply slide the bar over to 100% using the Tesla app when I wake up so it hits 100% just as I'm ready to leave. I've only needed to range charge for trips twice, but both times the charge completed within 10 minutes of leaving.
     
  6. johnnyS

    johnnyS Member

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    When going on a trip that will require charging away from home, just do a range charge before you leave. Sometimes public chargers are broken, slower than expected, or in use. While on the trip, if you can leave the car charging while you are doing something else, go for it. The last few miles added of a full charge are very slow. On a trip take advantage charging when it is available.
     
  7. David99

    David99 Active Member

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    The Leaf has less than 1/3 of the Model S battery size. So for the most part you will never have to charge to 100% on the Tesla. Set the limit to 80% and don't worry about when it finishes. If you want to, set the timer to start at midnight. That helps balancing the load on the grid yet you'll have the battery charged in the morning no matter what level you set it. It really doesn't matter if the battery sits at 80 or 90% for 2 hours before you start driving. If you charge to 100% (which you only need when making trips over 200 miles without a stop), then time it so it finishes just when you leave. Or just top it off in the morning manually as other have suggested. Cold temperatures make the battery age slower, so don't heat your garage. Warm temps will increase battery performance and useable capacity, but it also makes it age quicker. Elon once said about battery life, if you have the Model S in Alaska it will last 'forever'.
     
  8. David_Cary

    David_Cary Member

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    Just an aside. The battery stars at the dealer checkup mean absolutely nothing. Doesn't mean you don't have a great battery, it is just the stars are beyond worthless. Get a GID monitor if you want to really know.

    Each battery is a little different (I mean Leaf vs Tesla) but some things matter to all. Heat is your biggest enemy and Heat + 100% SOC is the worst. I'm sure your summers get hot but they are still probably shorter than a lot of us.

    Truly interesting there is no "end time" on the Tesla. Even if you ignore the battery life issues, there are other advantages. People with variable daily mileage and short off peak times of 4 hours. If they start at midnight, they might not finish by their 6 am leave time. Buy they want to start at midnight because that is the lowest rate unless needed, then they want to start earlier.

    The other issue is that you really want to start the latest possible to allow the battery to cool from the day's driving. If not, in a hot climate, you might be spending energy to cool the battery. Either way, the battery sees more heat than necessary.

    Come on Tesla, give us OCD types an end time charger already
     
  9. arijaycomet

    arijaycomet Member

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    Great replies! Thank you so much.....

    David_Cary, yeah that all makes a lot of sense. I really wish the end timer was there, it was just such a perfect feature on the Nissan. Good to know about the battery stars. I've never bothered with a GID monitor just because it was a leased car-- but having one in the Tesla would make more sense-- though my track record is such I'll only keep this car 2-3 years.

    Oh and I should clarify... my "heated garage" just keeps things above freezing. Our house is 60+ years old now.. the heater was already there when we bought the house (radiant style gas, fixed to ceiling). I usually set it to around 40-to-45-degrees in the winter. Otherwise the garage stays cool nicely in summer (never about 70) and never gets below 40-45 in winter based on heater. But it isn't like I'm heating the garage to 80 or anything stupid.

    And yeah, Cleveland, Ohio summers are hardly "harsh" -- humid and yes we have 90+ degree days but not that many of them. I'll probably just use 80% to 90% SOC for most days, and just not worry about it, going to 100% on the rare occasions I need it. But even the long trips I've mapped out are only 150-miles at MOST between superchargers....
     
  10. muleferg

    muleferg Member

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    Drove a 2012 Leaf for 2 years. In March 2014 received my Models S. I missed the end charge for about 3 months. I forgot all about it after that.

    IMG_2862.jpg
     
  11. jerry33

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

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    Whether you have a 14-50 or an HPWC, it's not too hard to figure out when the charge will end, and you also know when you're going to leave in the morning so you set the start time appropriately. Here in Texas if you're going out of state--and many places within the state--you will always be doing a range charge at home before you leave (progress in this area is being made, but it's slow). If you're in California, there's probably no reason to charge more than the daily maximum charge unless the weather is going to turn bad or there are some significant elevation changes.

    As far as I'm aware, the damage to the cells happen by leaving them full or empty for an extended period--particularly in hot weather.
     

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