4 ms·

The only thing that tops range anxiety for me is battery degradation anxiety. I would probably be totally fine with a lower range if I know that my battery can

The only thing that tops range anxiety for me is battery degradation anxiety. I would probably be totally fine with a lower range if I know that my battery can do 100 000 cycles.

londons_explore 4y ago
At the battery control system design stage, these two factors are mostly trade-off-able. For example, you'll get far far more cycles out of a battery if you only charge up to 80% and discharge down to 20%. Early hybrid cars used this to an extreme - and always kept the battery between 45% and 60%. By doing that you can get 50,000 cycles necessary to recharge and discharge every time you go up and down a hill.
tuatoru 4y ago
For a practical car, 200 to 500 full charge cycles per year is all that could happen. 200 for a suburban family car, 500 for an urban commercial vehicle. (200 cycles per year would be perceived by an owner as being "every day", because the days she's away on holiday or sick at home or WFH are not remembered. Nor would she remember that she only charges once on weekends.) 100_000 cycles is therefore 20 to (more likely) 50 years' use. That's a family heirloom, well outlasting the body, suspension, steering and interior of any car. I'd like to have that too. Edit: Er, that should be 200 to 500 years. Outlasting several chassis and interiors. Definitely heirlooms.
- konschubert 4y ago
  I think 20 years of use would be cool for a car! Of course you might be right that the steering would break first - but shouldn't that be replaceable? I can't see a reason while the car's body or the electric motors would not last that long.
- bryanlarsen 4y ago
  A full charge cycle is 0 to 100 and back. If you only do 20 to 80 as most owners do you get about ten times as many cycles. So a typical owner does well under 100 per year. 250,000 km is a reasonable expectation.
- dfadsadsf 4y ago
  You did math wrong. 100k cycles is 200 to 500 years of use using your assumptions. Indeed heirloom!
bryanlarsen 4y ago
The LFP batteries in the article have an expected life of 6000 cycles, which in real world usage corresponds to about 750,000 kilometers. (6000 is worst case cycle, which never happens in a car with a proper BMS). You're asking for a battery with an expected life span of 12.5 million kilometers.
- konschubert 4y ago
  750000 is amazing too! How many cycles does a normal car battery do?
  - bryanlarsen 4y ago
    2000 cycles for 200 - 250 000 km. Unless you fast charge to 100% regularly.

The only thing that tops range anxiety for me is battery degradation anxiety. I would probably be totally fine with a lower range if I know that my battery can do 100 000 cycles.

londons_explore 4y ago

At the battery control system design stage, these two factors are mostly trade-off-able. For example, you'll get far far more cycles out of a battery if you only charge up to 80% and discharge down to 20%. Early hybrid cars used this to an extreme - and always kept the battery between 45% and 60%. By doing that you can get 50,000 cycles necessary to recharge and discharge every time you go up and down a hill.

tuatoru 4y ago

For a practical car, 200 to 500 full charge cycles per year is all that could happen. 200 for a suburban family car, 500 for an urban commercial vehicle. (200 cycles per year would be perceived by an owner as being "every day", because the days she's away on holiday or sick at home or WFH are not remembered. Nor would she remember that she only charges once on weekends.) 100_000 cycles is therefore 20 to (more likely) 50 years' use. That's a family heirloom, well outlasting the body, suspension, steering and interior of any car. I'd like to have that too. Edit: Er, that should be 200 to 500 years. Outlasting several chassis and interiors. Definitely heirlooms.

konschubert 4y ago
I think 20 years of use would be cool for a car! Of course you might be right that the steering would break first - but shouldn't that be replaceable? I can't see a reason while the car's body or the electric motors would not last that long.
bryanlarsen 4y ago
A full charge cycle is 0 to 100 and back. If you only do 20 to 80 as most owners do you get about ten times as many cycles. So a typical owner does well under 100 per year. 250,000 km is a reasonable expectation.
dfadsadsf 4y ago
You did math wrong. 100k cycles is 200 to 500 years of use using your assumptions. Indeed heirloom!

bryanlarsen 4y ago

The LFP batteries in the article have an expected life of 6000 cycles, which in real world usage corresponds to about 750,000 kilometers. (6000 is worst case cycle, which never happens in a car with a proper BMS). You're asking for a battery with an expected life span of 12.5 million kilometers.

konschubert 4y ago
750000 is amazing too! How many cycles does a normal car battery do?
- bryanlarsen 4y ago
  2000 cycles for 200 - 250 000 km. Unless you fast charge to 100% regularly.