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Comment by tomc1985 | Hacker News Reader

tomc1985

Can it do this consistently without destroying the lifetime of the battery?

Yes, it can easily do this hundreds of times with minimal loss of capacity (e.g. 5%) so long as temperature is well controlled, but depth of discharge is not really 0% (fully discharged) and it's not really 80% (fully charged).

They're made of of many hundreds of cells at different charge points, but likely 10-20% is as discharged as you're likely to get (without leaving the vehicle sitting for weeks on end) and 80% is as charged as you'll get. They have traded power density for lifetime and "charging rate".

Hundreds of times for an appliance like a car that should last 20+ years is absolutely dreadful. Plenty of people go through a gas of tank a week. A single year is 52 full charges. 5 years already puts it well above 250 charges.

You wouldn't be exclusively charging at those speeds, though.

Why not? I don't have an EV but in the US I've heard of people outfitting their homes with 240V sockets for higher-speed charging

240v isn't high speed charging for EVs.

240V isn’t supercharging. That’s level 2. The difference between level 2 and supercharging is 17 kilowatts vs. 140 kilowatts.

Most people probably wouldn’t require every charge to be fast this though. Many slow charging options, which do not put as much strain on the batteries, exist for the home and the workplace.

With typical EV workloads you'd only do this type of fast charging on a roadtrip or similar. The remaining time you'd be charging at home at much lower rates.

Not to say there aren't people who only charge at superchargers, but as L2 availability increases I imagine that will be less and less common.

Most people live in apartment buildings, with tens of cars around the same building. I doubt at-home charging will be easy to scale - at the very least this would require major grid redesigns in most cities.

putting 120 volt chargers in is really easy (you just need an outlet and a cable).

How do you do that from the 8th floor? And will the power grid work well once 30 cars are charging each night from the same grid?

people don't generally park their cars on the 8th floor. They park them in a parking lot, so that's where you would put the outlets. Power grids will have to expand to deal with the excess demand, but the transition to electric vehicles is happening slowly, so there's plenty of time to do so. Also, since electric vehichles are basically just giant batteries, they pair very well with solar and wind power. As solar power makes up a larger percentage of total power generation, it will become much cheaper to charge vehicles during the day when most of them are sitting in office parking lots. This will significantly reduce the "duck curve" problem, and make solar power even more effective than it currently is.

I have an early 20 year old EV...

The range is about 100 yards before the electrics die... I can get 500 yards if I drive carefully...

Luckily the charge time has also sped up with age - I can recharge in about 5 minutes to drive the next 500 yards!

One tank of gas amounts to around 700km. After 5 years it would amount to ~175.000km. This car will most likely not live for 20 years without mayor replacements and repairs.

Not sure which car you've been using but cars have been getting quite reliable.

I have a 2001 BMW 330i that's on around 363k miles (~580,000km) and still running the original factory drivetrain. The only parts replaced so far are wear parts in suspension and brakes (common with EVs) and some coolant pipes (probably also needed in EVs).

????? At 175 000 km, you're barely getting into the "old" territory. I've driven cars that had 350k and were still doing fine. The only major replacement you should have had by then is changing the timing belt. And even then, some cars have a timing chain that just straight up doesn't break.

> so long as temperature is well controlled

There are a lot (vast majority?) of climates for which this would be really hard to do.

Yeah... My priority would be to have a 10-20kwh (for 2-3) days of use battery at home (which needs to do 3000+ cycles) charged via solar and then recharge the car slowly overnight.

There is a cooling system to manage heat. Also, apparently the real issue for most tesla batteries is going above 90% or below 20% ish

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