Short · Cars
Why does an electric car charge fast to 80%, then crawl to full?
Elon Musk compares charging to parking: in an empty battery, lithium ions zip into spots, so the charger runs flat out. As it fills, they hunt for space, and forcing them in fast can plate lithium metal, so the car turns the power down. In a Model Y, 10 to 80% takes about 30 minutes and the last 20% about as long again, so road trips go faster with short, frequent stops.
Opens Charge Curve. Change the same thing yourself.
Transcript
Why does an electric car charge to eighty percent fast, then crawl to full? Elon Musk compares it to parking. Lithium ions fill spots in the battery like cars in a parking lot. When the lot is empty, they zip right in, so the charger runs flat out. As it fills, each one has to hunt for a spot, and forcing them in too fast can plate lithium metal inside the cell. So the car turns the power down. In a Model Y, ten to eighty percent takes about thirty minutes, and the last twenty takes about as long again. Those last miles are the slowest you can buy, so road trips go faster with short, frequent stops. Try it yourself at Explainer Tools dot com.
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Learn more about EV charging
Charging power falls as the battery fills. The guide explains what the car is protecting, how other cars compare, and where this model stops.
- Topic guideWhy does EV charging slow down after 80%?Lithium plating, heat, road-trip stops and how other cars compare.
- Interactive demoBuild an AtomBuild a lithium atom, then take one electron away to make the ion a battery moves.by PhET Interactive Simulations
JournalWhy does an electric car charge fast to 80%, then crawl to full?Near empty, lithium ions slot into the battery easily and the charger runs flat out. Near full, pushing them in fast risks plating lithium metal, so the car turns the power down, and the last 20% takes about as long as the first 70.