Why the fastest EV charger isn't always the smartest choice

Imagine this. Your EV battery is getting low and your car sends you off the highway to the fastest charger around, ignoring the closer (but slower) charging point.

And yet, by the time you plug in, the slower stop you passed could have already gotten you back on the road, while you're still waiting at the charger that was meant to save you time.

This happens when a navigation system does what it is essentially designed to do. It chooses the best charging point according to the charger's speed and power. But that's only one piece of a much more complicated puzzle, and understanding all of its parts is crucial when choosing which charger will be the best option for your journey.

That's where EV charging stop selection comes in.

Instead of asking "which charger is fastest?", it asks "where should this driver charge so the whole journey goes quicker?". And those two questions can have very different answers.

Read more: EV interest is rising. Now the ownership experience must deliver

Why charger power isn't the whole story

When your EV battery is running low and you're on a tight schedule, the logical assumption would be that the charging station with the most power should be the quickest to get you back on the road. But a more powerful charger doesn't necessarily charge your car faster.

At least not by itself.

That's because every charging session depends on two limiting variables: what the charger can deliver and what the car can take. The speed at which your vehicle charges depends on the combination of the two, and your car won't pull more current than it was built to handle, no matter what the plug can offer.

Temperature plays a part too.

A car's battery management system can slow charging down when the battery is too cold or too hot, which protects the battery but costs you speed. What this means in practice is that a cold battery on a winter morning (or an overheated battery on a particularly hot summer day) can have a painfully slow charge even at a high-power station.

And this can add serious delays to your overall journey.

Read more: Redefining the automotive experience at the speed of agentic AI

The fastest charger vs the fastest trip

Your car's limits can shrink the gap even more. On paper, choosing a charging stop looks simple: find the most powerful charger nearby and head straight for it.

But on the road, the right choice depends on more than the number on the plug, starting with how far you have to drive off your route to reach it and whether your car can actually accept the speed that charger promises.

Then there's the question of how much to charge. You don't need a full battery at every stop. Often the smarter move is to take just enough range to reach the next one, and that can have a big impact on how much time you need to spend at each station.

None of this means the high-power charger is the wrong pick. If it's close to your route and your car can use a good share of its output, it may well be the best stop, detour and all.

What the comparison really calls for is a system that can weigh detour time, your car's charging limits and the range you need for the next leg, all at once, instead of ranking stops on a single number.

This is where a route-aware approach to planning your charging stops really makes a difference.

Read more: When charging an EV becomes hard work, Cariqa clears a path

How route-aware charging works

It starts with where to look. Rather than hunting for the single highest-rated charger in the area, a route-aware approach finds charging locations that sit along or near your planned route.

Each option is then checked against the route itself. It looks at factors such as how far it pulls you off your path and how much time that adds to your overall trip.

A stop five minutes away impacts your journey much less than one that needs a long detour, regardless of its rated power.

And then there are the limitations of the car itself. How much range it has, how much power it can actually take from a given charger, and how much range it needs for the next leg are all important pieces of the charging puzzle.

When combined, these factors show how useful a charging session will really be for your particular car, on this particular trip.

HERE provides mapping, routing and EV charging data that make this kind of comparison possible.

It helps identify charging locations, work out route detours and account for range. Turning that into a recommendation for a specific car still takes details about the car's battery and charging behavior, which the navigation system or the carmaker's platform provides.

In short, the fastest charger on paper is not always the fastest choice on the road.

Frequently asked questions

Does charger power determine charging time?

No. Charging time also depends on how much power the car can accept, and the battery management system may cut that power when the battery is outside a suitable temperature range.

Can the fastest charger slow down a trip?

Yes. If getting there adds a detour, or the car can't use the charger's full power, you can lose time. Door-to-door trip time, not time at the plug, is the comparison that counts.

How much should you charge at each stop?

Enough to comfortably reach your next planned stop or your destination. Filling the battery by default isn't always the best move, because the right amount depends on what's coming next.

What matters besides speed when choosing a charger?

Where the charger sits relative to your route, what your car can actually draw, and how much range you'll need after you leave. All three affect whether it's really the better stop.

How can navigation choose a better charging stop?

By comparing candidate chargers against the route and the car's range for the next leg. HERE supplies mapping, routing and EV charging data to support that comparison, alongside vehicle inputs.