For EV drivers traversing the great state of Wyoming, the Smith’s grocery store in Rock Springs is an oasis. It’s just off Interstate 80, there’s a Petco across the street, and it has six plugs promising to charge at 350 kilowatts. At that rate, a Tesla Model 3 could go from empty to full in the time it takes to hit the bathroom and grab a Snickers.

But when I limped up to the station last month — in a Rivian R1S crammed with one dog and two kids — that 350 kW may as well have been a mirage. Rivian’s SUV charges at 220 kW at best, and the charger itself crimped the hose to just 50 kW. With one pit stop, our carefully planned seven-hour road trip got two hours longer.

For starters, an EV itself can only suck up electrons so quickly. Of the 55 electric models now available in the U.S., half charge above 200 kW and only five can charge at 350 kW. Those speeds are further compromised when it’s very hot or very cold. Temperature extremes can damage a lithium-ion battery, so automakers program their cars to slow a charge in certain temperatures.

That gap risks hurting EV adoption in the U.S., where charging speed has become a marketing metric. Automakers like to trumpet how quickly their cars can go from 10% or 20% full to 80%, while public charging stations tend to display maximum charge rate — not average or expected — right on the machines. Some 17% of U.S. public chargers are rated 100 kW-plus, according to BloombergNEF, compared with 10% in the UK and 2% in the Netherlands.