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A spare "battery" would make sense

Discussion in 'The UK and Ireland' started by Rognjak, Jun 22, 2014.

  1. Rognjak

    Rognjak Member

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    Just as ICE cars carry a spare can of fuel, it might be a good idea for Tesla to develop a rechargeable spare battery array, carried in the frunk, that could be plugged in to give an extra , say, 50 miles range as and when needed. This would completely remove range angst.
     
  2. RandyS

    RandyS Fan of Elon

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    Lots of things to consider....Here's a few to get the conversation started...

    * Would require about 17-20 kWh...Several thousand $$$ in cost.
    * Additional weight on already heavy car changes handling and other characteristics
    * New configuration now has to take into account the chance that the battery might come into the passenger compartment in a front end collision

    My gut reaction is that an 85 kWh battery already gets rid of most of the effects of range angst...
     
  3. Hodginator

    Hodginator Member

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    As the super charger population grows, range anxiety will go away. They are doing a good job of rolling them out quickly.
     
  4. bonnie

    bonnie Oil is for sissies.

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    Carrying the extra weight around would cause you to lose range.
     
  5. jerry33

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

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    Having driven my Model S over 26,000 miles in Texas, where 400 miles often doesn't get you out of the state and 700 miles is a comfortable day's driving, there is no range anxiety--even if there are some long charging times at RV parks because Tesla hasn't built out their North American Supercharger network yet. I can't imagine that you would ever have range anxiety in the UK or Ireland. London to Aberdeen is only a bit more than 530 miles.
     
  6. Peter_M

    Peter_M Member

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    The car already has spare battery capacity. When it says zero, there's still about 17 mi / 27 km left. If that's not enough to make you comfortable, just pretend you have a 75 kWh battery and plan your trips and charging accordingly. The remaining 10 kWh (plus the below-zero reserve) is your "spare battery". No need to complicate things with extra hardware.
     
  7. mknox

    mknox Well-Known Member

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    I think as EVs become more prevalent, something like this makes more sense than carrying around spare batteries. I mean, who carries spare cans of gas with them any more?
     
  8. dsm363

    dsm363 Roadster + Sig Model S

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    Yeah. I don't know of anyone that carries extra gas in the car. Simply too dangerous for a rare event.
     
  9. brianman

    brianman Burrito Founder

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    Jeeps that go offroading or want to be prepared for the zombie apocalypse. Other than that, I don't really see it much.
     
  10. SlyWombat

    SlyWombat Member

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    Yup, so those folks can carry a set of solar panels in their model "X" instead.
     
  11. roblab

    roblab Active Member

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    If gas cars could tell you how many miles you had left in the tank, anywhere near accurately, they wouldn't run out of gas so much.

    Where I see EVs run out of charge is on trips where a newish EV driver thinks he can go 80 mph, up hill, and ends up 5 miles short of making it to the supercharger. No one told him to charge enough to get a buffer, and to watch the buffer, and if it starts shrinking, slow down. But the EV tells you exactly how many miles you have left.

    This Charge Truck (AAA) only gives you 5 miles of range. You call, and if there is a charge truck near you (like, where, Seattle?) they come out (might take a while) and give you a 10 minute charge. That's at 10 amps, like at your garage 14-50. They call it a fast charge.

    Wouldn't it be easier to slow down 5 mph and make it to your charger?

    Non Tesla Cars of course, have a bigger problem, running out of charge with only one fourth the range. But Teslas running around doing daily errands won't need a Charger Truck.

    And Teslas out on the far wild freeways, 200 miles out, won't find a Charger Truck anywhere nearby. And they will probably need more than 5 miles.
     
  12. miimura

    miimura Active Member

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    AAA has trucks that have CHAdeMO and J1772. However, it seems the on-board generator may only be about 20kW, delivering about 15kW of DC through the CHAdeMO. Amperage on the J1772 is unknown. Even the driver didn't know when I saw it at a Plug-In America event last fall.
     
  13. Ampster

    Ampster Member

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    That is the solution that appeals to me. I wouldn't want to have the extra weight and cost of a spare battery when there is a simple solution such as that.
     
  14. AnOutsider

    AnOutsider S532 # XS27

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    Ya know, I have no numbers on this, but I suspect it might not be as much as one might think. I just got back from a mini-roadtrip, and I had the family all piled in, suitcases in the back (even the footwell space was full) and a fully-loaded frunk. I got my best WH/m driving down the highway. Now, around town, it was higher, but it's always like that for me.

    It makes me think that no matter the cargo, once you get rolling, the weight differences are negligible. Now, I don't know how much a spare battery would weigh, but if you're doing highway driving and it's not a ridiculous amount, it could have some benefit.
     
  15. bonnie

    bonnie Oil is for sissies.

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    So you're saying you'd buy a spare battery to carry around ... and deal with how to hook it up and such?

    As far as how much it would weigh, that's not so difficult to guess. There's about a 183# diff between the ModelS 85 and Model S 60 (Curb weight: 4647 lbs 85 kWh, 4464 lbs 60 kWh) ... so it would stand to reason that if you wanted to put a 25kwh pack in the car, you'd be looking at about 183# bare, plus case/hardware for hooking up. And you could probably extrapolate the price (plus a few extra dollars) the same way. You'd lose much of the frunk.

    Worth it? You tell us.
     
  16. AnOutsider

    AnOutsider S532 # XS27

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    Where did I say that? The majority of my post was more about (my astonishment regarding) weight not seeming to matter much once moving since that was the only part I quoted...
     
  17. David99

    David99 Active Member

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    Tesla did that. They added an extra battery that extends the industry standard of 80 miles to 260. To make it easier, more cost effective and smarter, (so both can be cooled and heated and charged in sync) they decided to just combine the main battery and the extra battery into one housing.

    Seriously, though, an extra, separate battery makes no sense whatsoever. Why built a second battery in the car that isn't used and adds extra weight. It makes much more sense to just increase the main battery capacity. And that's what Tesla did. They made the battery as big as reasonably possible. Elon said many times, they could make a car with a battery that goes 1000 miles but it would be very heavy and expensive that very few people would buy. An emergency gas tank is for people that ignore instruments and don't pay attention to how much gas they have. The Model S shows you nice and clear how much you have left making it simple to plan.

    As was pointed out, the Model S has an emergency buffer passed 0 miles. It's not good for the battery but it's OK in case of an emergency. 10-15 miles.
     
  18. palmer_md

    palmer_md Member

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    Want an extra 50 miles, tow a Nissan Leaf as a backup. haha.
     
  19. bonnie

    bonnie Oil is for sissies.

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    Funny guy. But, umm, why not?
     
  20. Johan

    Johan Took a TSLA bear test. Came back negative.

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    To adress the OP: But of course we would soon need a second spare battery in the trunk for when the first spare runs out... See where this is going?
     

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