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Model S (Refresh) 48 v 72 Questions

Discussion in 'Model S: Battery & Charging' started by SleepingAtLast, May 28, 2016.

  1. SleepingAtLast

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    hello there.. i tried looking for answers to these questions and can't seem to find them, so i apologies if these have been asked already!

    just received my refreshed model s 70d. was curious where i can find out if my car has 48v or 72v charger? i know it's currently standard as 72 and needs to be "unlocked" to get to it, but my delivery specialist said something about mine being equipped with 72, but i can't seem to find out where to find that info in my car? any clue? i'm assuming he was just letting me know that mine was indeed delivered with that option, if i wanted to pay to unlock it.

    secondly, does having 72 "unlocked" allow superchargers to charge my car faster too, or just overnight home charging?

    lastly, my delivery specialist recommended that i charge it to the highest point in my "daily" usage (90%).. i'm curious: since it's shipped with a 75k battery that i have not "unlocked", does that mean i have less reason for concern to have it charge to 90% daily of 70k? not sure if this question makes sense, but hopefully it does! want to make sure i'm treating this beautiful new car right, as it's my first electric!

    thanks!!
     
  2. dhrivnak

    dhrivnak Active Member

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    The battery normally only charges to 90% to preserve the battery. That is normal and good. Just ramp to 100% when you need it. As for super charging the on board charger is bypassed so one at 40 amp or 72 will super charge the same.
     
  3. Boatguy

    Boatguy Member

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    Plug it into your home charger, select Controls and then Charging and see if you can adjust the Charge Current. It will either max out at 48a (not volts), or you'll be able to adjust it up to 72a.

    The charger converts AC from your house into DC for the batteries. Superchargers deliver high voltage DC and bypass your onboard charger entirely, so the 48/72 has nothing to do with the superchargers. So as dhrivnak says, you'll get the same charging at a supercharger, irrespective of whether you unlock the 72.

    The advantage of the 72a charger is at destination chargers like hotels with an HPWC, where you'll be able to charge faster. At home the 48a charger will charge your car overnight and normally you don't care if it finishes at 2am or 5am.
     
  4. Pollux

    Pollux Member

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    Hi, @SleepingAtLast

    To determine whether you received a 72A charger, you will need to consult your Motor Vehicle Purchase Agreement (MVPA). Look for a line item of $1500 for a charger. If you have that line item, you've got the 72A charger. Otherwise, you've got a 48A charger. I'm assuming that your car was built after they switched to the new 48/72A arrangement. I am aware of no way to verify what kind of charger you have based on normal user controls and status in the car. I'm reasonably confident that the Service Center can tell you; and you could also try sending mail to [email protected].

    That said, I am under the impression -- but not the certainty -- that the 48->72A charger switch implies a different, physical charger module embedded in your car. As far as I know, there is no "software unlock" of an upgrade from 48->72A.

    Re SuperCharging -- the SuperCharging process uses a different method than the "regular" charging process. SC uses Direct Current (DC) at high voltage and amperage. "Regular" charging -- basically everything EXCEPT Supercharging, to wit, all other third-party chargers and whatever charging arrangement you have at home -- uses Alternating Current (AC), which is then converted by the 48 or 72A "charger" to Direct Current, which goes into the battery pack. The batteries all use DC. One reason Supercharging goes faster is that there is no AC/DC conversion involved -- that 48A/72A charger is bypassed.

    90% charging rule applies no matter what the battery size. As @dhrivnak says, if you run into situations where you think you need 100%, just do it. No worries. That said, Superchargers are sufficiently prevalent now that, if you are doing driving within reasonable distance of highways and SC outposts, then you won't have to worry about charging to 100%. For example, when I first drove from Boston to Washington, DC, in November, 2013, I carefully charged to 100% the night before, mapped out what I would have to do to make it to the nearest Supercharger to me in Darien, CT, drove at 50 mph to lessen wind resistance and extend my range, turned off the cabin heat and just used seat warmers, turned on range mode. My wife questioned the wisdom of our large investment in a car that seemingly couldn't keep up with traffic and keep its passengers warm. :) Today... when I make the exact same trip... I might even forget to charge at all the night before. I might set out with 150 miles of range out of my possible 265. But I can hit a Supercharger in Auburn, MA, "tank up", and be on my way. The same trip I did 3 years ago at low speed and lacking heat is now a trip I make at regular highways speeds... well, where regular is defined as being in the upper third of traffic based on speed, with more heat than anyone would want and never bothering with range mode.

    Good luck,
    Alan

    P.S. I wish I was as smart as @Boatguy. Yeah, trying to dial up the charging process beyond 48A will tell you... ASSUMING that you have a >48A source to charge from. If your home charging circuit is confined to, say, 40A, then you still won't be able to tell.

    P.P.S. The "smart as @Boatguy" comment was meant seriously, not sarcastically. I hit my forehead as soon as I saw his post. :)
     
    • Informative x 1
  5. eclipxe

    eclipxe Member

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    No, that is precisely what it is. All cars are now capable of 72A but locked with software to 48. I believe the upgrade after deliver is $1900
     
    • Like x 2
  6. SleepingAtLast

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    awesome, thanks for the info! so appreciate it!
     
  7. nwdiver

    nwdiver Active Member

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    I agree this is probably true... but WHY?!?! With the older Teslas it made sense... they were physically installing a second charger... but why limit the new cars to 48A?
     
  8. Fiver

    Fiver Member

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    Because money. That's why.

    And it's not probably true, it is true. Go to the tesla design studio and look at the little fine print at the bottom in the charger section.
     
    • Informative x 1
  9. wdolson

    wdolson Active Member

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    Having a 72A charger in the car, but not having access to a wall unit capable of 72A is a waste of money. I initially ordered the 72A charger, but after consulting the electrician our house can only really support the 60A breaker for the 48A charger and putting in a 72A charger would probably require paying the electric utility to upgrade service to the house which is getting into many multiple $1000s. So I downgraded to the 48A on the car.

    If I move and can put in a 72A at the next house, I can pay to have it upgraded later. The only reasons I would move from this house is if it was condemned for some reason (unlikely), or I have enough cash to build a new house on acreage at which point I'd probably not be worrying about the extra $400 to turn on the 72A charger after delivery.
     
  10. FlatSix911

    FlatSix911 918 Hybrid

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    It's nice to have the 72A option, although most folks only need 48A charging overnight. (4hrs vs. 6hrs)

    upload_2016-5-30_19-11-42.png
    upload_2016-5-30_19-12-24.png
     
  11. Tanquen

    Tanquen Member

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    I was kind of upset to learn after locking in the order, that it's a software switch and not a hardware purchase. At the time it only described getting the higher amperage charger and the price now they've changed that to stay that you can purchase it afterwards for a higher price. I've asked in vain that the option be removed as I did not know it was only a software setting and could be purchased later if you decided you really needed it. Which is actually kind of nice have the car for a while then you can decide whether you really need it but they didn't tell me that in the beginning. Just adding that to the not feeling great about the car's purchase, reading up on all the issues and hoping mine isn't full of them. :(
     
  12. TexasEV

    TexasEV Active Member

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    Most people who get it (or the previous dual chargers) don't do it for overnight home use. It's helpful to have when traveling, when charging time can make a difference.
     
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  13. mikeash

    mikeash Active Member

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    The same reason the new 70s are actually 75s which are software limited to 70, and the same reason the P90D non-Ludicrous is limited in software, and Ludicrous is just flipping a switch.

    Which is to say, it's some combination of covering higher warranty costs (more stress on the components) and making a larger profit.

    If Tesla wants to provide 48A standard and 72A as an upgrade, it may well end up being cheaper for them to install a software-limited 72A charger in every car than it is to install 48A hardware in some cars and 72A hardware in others. Or it might cost more but they figure they'll make the extra cost back from post-purchase upgrades.

    Either way, it's the way things are going now. Lots of products are differentiated by software rather than hardware these days. I understand the frustration, but it does make a certain amount of sense.
     
  14. nwdiver

    nwdiver Active Member

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    Hmmm... hadn't considered that... that does make sense... kind of like over clocking your computer but without voiding the warranty.

    I wonder if they're shooting from the hip or if there's actually failure data...

    LOL... if this trend keeps up every car is going to be physically identical aside from the color... the options are just unlocked via software. Brave new world for hackers.
     
  15. RichardL

    RichardL Member

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    I think your idea about the 'extra' safety of charging a software limited 70 is correct, but I don't know if anyone has ever been certain - presumably some of the early 40 users might know.

    However, the reality is that its simple to set at 90% and for most that is way more than they need on a daily basis. When you take a trip, charge to 100% and you will probably do slightly less damage than the small damage we all do when charging briefly to 100%
     
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  16. ruby110

    ruby110 Member

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    @mikeash: are you sure about Ludicrous being enabled by software? I think it requires a different material for the fuse link. Are they really using the new material in all performance cars?
     
  17. mikeash

    mikeash Active Member

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    Ludicrous needs new materials when upgrading the P85D and I think some of the early P90Ds, but later P90Ds come with the special fuses and contactors already installed.

    For example, someone in Abu Dhabi got their P90D upgraded to L by a tech using a laptop and a chrome underline:

    L or no L?
     
  18. wdolson

    wdolson Active Member

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    From what I've read the 90Ds and P90Ds all have the same battery pack with the heavy duty fuse already installed. If you wanted to hack the car and had a large drive unit, you could turn any 90D into a P90DL by replacing the rear drive unit and hacking the firmware. Though Tesla probably wouldn't be too happy about it.
     
  19. ruby110

    ruby110 Member

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    @mikeash: very interesting, thanks.
     
  20. wagonwheel

    wagonwheel New Member

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    I believe what the OP was referring to with his last question, ("lastly, my delivery specialist recommended that i charge it to the highest point in my "daily" usage (90%).. i'm curious: since it's shipped with a 75k battery that i have not "unlocked", does that mean i have less reason for concern to have it charge to 90% daily of 70k?"), isn't it true that with a 75kWh battery that is being software limited to 60kWh, charging to 100% will actually only be 80% of it's true capacity (60kWh/75kWh = 80%)?
    Thus there should be no concern regarding long-term battery degradation due to frequently charging all the way up to 100%, because it's not really at the battery's 100% capacity.

    Does this sound accurate, or is my thinking twisted?
     

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