5 ms·

99% of commutes are less than 200 miles. Current car batteries support large numbers of charge cycles and have a capacity that's high enough for these trips. H

99% of commutes are less than 200 miles. Current car batteries support large numbers of charge cycles and have a capacity that's high enough for these trips. However, many drivers do a bunch of 500+ miles drives per year; 1, 10, or 100, depends on the driver. At 500+ miles, battery anxiety starts to kick in. An electric car that combines current high-cycles-low-range batteries with a smaller low-cycle-very-large-range battery for those 10 500+ miles trips per year would be a killer product. We are talking here 1000+ miles without charging, which is kind of much farther than what most cars can get without re-fueling. I do maybe one 500+ miles trip per month. That'd be ~24 cycles / year, such that these batteries would have a lifetime for my use of ~40+ years. That's more than enough for me. There are a bunch of companies working on hybrid battery designs that combine different technologies to serve different purposes. Some of them are already hitting 800+ miles in real-world tests.

jqpabc123 5y ago
The tricky part is the recharging. The car can't possibly know if the owner is planning a 500 mile trip the next day. The only "safe" approach is to assume they are and top up all batteries every time it is plugged in. If the owner plugs it in every day, how does this impact the usable life of this new battery?
- notreallyserio 5y ago
  The car doesn't necessarily have to know that someone is planning a 500 mile trip, the car operator can tell it to top up overnight when necessary.
  - nicoburns 5y ago
    What could possibly require you to take an unexpected 500 mile trip at short notice?
    - notreallyserio 5y ago
      And without the opportunity to charge at a supercharger on the way?
  - jqpabc123 5y ago
    <i>...the car operator can tell it to top up overnight when necessary.</i> The car operator may not always know when it's necessary --- assuming he is not psychic. He may just top up to be on the safe side.
    - gameswithgo 5y ago
      * With lithium ion you don't want to sit at 100% all of the time, but it is fine to always keep it topped off to ~80% or so. Topping it off daily is good. * If you are someone who doesn't want to worry about not going to 100% all of the time the new iron based batteries (featured in base model 3 right now for instance) don't care, you can let those sit at 100%, and they are safer too. The downside is less total range range and/or more weight.
      - jqpabc123 5y ago
        With lithium ion you don't want to sit at 100% all of the time ... Someone who drives infrequently (a senior for example) or has multiple cars could easily leave a car plugged in for days.
        sliken 5y ago
        Sure, but Tesla recommends charging to 90% for daily use (except for LFP batteries), personally I charge to 85% to help increase battery life. It also helps the battery when it gets cold, the car will use power to help keep battery warm, which also helps increase battery life.
      - Tagbert 5y ago
        GM in their Volt and Bolt holds back a percentage of the battery capacity so that at 100% of charge the battery pack is only charging to 85-90% and when it discharges to 0% the pack is actually not at zero. They do this to limit stress on the cells and to ensure longer service life for the battery pack.
    - fomine3 5y ago
      How much possibility? Like once per a decade? Edge case could be ignored by patience at charging station or rent a car.
sliken 5y ago
> At 500+ miles, battery anxiety starts to kick in. I have a Tesla model 3, it's got a decent nav system, is aware of the battery state, current trip, average speed and the like. For me it makes range anxiety a non-issue. I had a 1200 mile road trip, did no preplanning, just filled the car with luggage and family, hit nav, and said "navigate to <1200 mile distant city>". The Tesla experience is pretty transparent and the superchargers are pretty frequent and reliable. I've yet (over 30k miles) expected to charge at a supercharger and not been able to. Generally I had more than one place I could stop and once charging it would give feedback like "charge x minutes to reach next charging station with 15% battery left". Sometimes we'd charge a bit extra waiting on someone and it would automatically pick a further charging station. While driving the car would helpfully say things like "You'll arrive at the next charging station with 15% battery left if you keep under 75 mph". Despite going through of some of the lowest density charging areas like eastern Nevada or southern Wyoming I had no issues. The charging stations I used were quite close to the major highways, and the strategy we used was to fill up to 50-75% and recharge when we had 10-20% left. This involves more stops, but also maximized charge speed, often 550 miles/hour or more. Charging slows as the battery gets more full. With 3 people and a dog the car was generally ready for departure about as quickly as the rest of us. I did however carry power adapters for 120v, 220v, and the popular J1772 just in case, haven't used them, except when it's free like at some Universities (like Stanford) or businesses (like 2 hours free at Target).
- maxwell86 5y ago
  When you are talking about super chargers, are you extrapolating to the whole planet earth? Or have you actually driven your Tesla across all 5 continents ?

jqpabc123 5y ago

The tricky part is the recharging. The car can't possibly know if the owner is planning a 500 mile trip the next day. The only "safe" approach is to assume they are and top up all batteries every time it is plugged in. If the owner plugs it in every day, how does this impact the usable life of this new battery?

notreallyserio 5y ago
The car doesn't necessarily have to know that someone is planning a 500 mile trip, the car operator can tell it to top up overnight when necessary.
- nicoburns 5y ago
  What could possibly require you to take an unexpected 500 mile trip at short notice?
  - notreallyserio 5y ago
    And without the opportunity to charge at a supercharger on the way?
- jqpabc123 5y ago
  <i>...the car operator can tell it to top up overnight when necessary.</i> The car operator may not always know when it's necessary --- assuming he is not psychic. He may just top up to be on the safe side.
  - gameswithgo 5y ago
    * With lithium ion you don't want to sit at 100% all of the time, but it is fine to always keep it topped off to ~80% or so. Topping it off daily is good. * If you are someone who doesn't want to worry about not going to 100% all of the time the new iron based batteries (featured in base model 3 right now for instance) don't care, you can let those sit at 100%, and they are safer too. The downside is less total range range and/or more weight.
    - jqpabc123 5y ago
      With lithium ion you don't want to sit at 100% all of the time ... Someone who drives infrequently (a senior for example) or has multiple cars could easily leave a car plugged in for days.
      - sliken 5y ago
        Sure, but Tesla recommends charging to 90% for daily use (except for LFP batteries), personally I charge to 85% to help increase battery life. It also helps the battery when it gets cold, the car will use power to help keep battery warm, which also helps increase battery life.
    - Tagbert 5y ago
      GM in their Volt and Bolt holds back a percentage of the battery capacity so that at 100% of charge the battery pack is only charging to 85-90% and when it discharges to 0% the pack is actually not at zero. They do this to limit stress on the cells and to ensure longer service life for the battery pack.
  - fomine3 5y ago
    How much possibility? Like once per a decade? Edge case could be ignored by patience at charging station or rent a car.

sliken 5y ago

> At 500+ miles, battery anxiety starts to kick in. I have a Tesla model 3, it's got a decent nav system, is aware of the battery state, current trip, average speed and the like. For me it makes range anxiety a non-issue. I had a 1200 mile road trip, did no preplanning, just filled the car with luggage and family, hit nav, and said "navigate to <1200 mile distant city>". The Tesla experience is pretty transparent and the superchargers are pretty frequent and reliable. I've yet (over 30k miles) expected to charge at a supercharger and not been able to. Generally I had more than one place I could stop and once charging it would give feedback like "charge x minutes to reach next charging station with 15% battery left". Sometimes we'd charge a bit extra waiting on someone and it would automatically pick a further charging station. While driving the car would helpfully say things like "You'll arrive at the next charging station with 15% battery left if you keep under 75 mph". Despite going through of some of the lowest density charging areas like eastern Nevada or southern Wyoming I had no issues. The charging stations I used were quite close to the major highways, and the strategy we used was to fill up to 50-75% and recharge when we had 10-20% left. This involves more stops, but also maximized charge speed, often 550 miles/hour or more. Charging slows as the battery gets more full. With 3 people and a dog the car was generally ready for departure about as quickly as the rest of us. I did however carry power adapters for 120v, 220v, and the popular J1772 just in case, haven't used them, except when it's free like at some Universities (like Stanford) or businesses (like 2 hours free at Target).

maxwell86 5y ago
When you are talking about super chargers, are you extrapolating to the whole planet earth? Or have you actually driven your Tesla across all 5 continents ?