Why Your EV Sometimes Charges More Slowly in Winter

When it’s cold outside, fast charging can sometimes look as if the charger isn’t working properly. Especially if you’re used to much higher kW figures and suddenly see less power. The key thing to know is this: The charging speed is a combination of both the ability of the charger to provide power and the ability of the car to receive the power. Especially the latter suffers from cold conditions in winter as it deliberately charges more slowly to protect the battery and the electronics until the battery is warm enough.

How Cold Affects Charging Power

An EV battery charges fastest when it is operating in its ideal temperature range. Around 22 to 25°C is considered optimal. In the cold, the chemical processes inside the battery slow down and electrical resistance increases. That means the battery cannot absorb energy as quickly as it can in mild temperatures. Very high charging power would put more strain on the battery and high-voltage electronics, so many vehicles automatically reduce charging power in winter. This is not a malfunction. It’s a protective mechanism set by manufacturers.

So if you charge your EV in sub-zero temperatures, lower kW values at the start of the session are completely normal. They often increase later, once the battery has warmed up.

Why it Is Especially Noticeable in the City

Many drivers notice slower charging most in urban day-to-day use. The reason is simple: on short trips, the battery often doesn’t heat enough. Some models need up to an hour of driving in winter for the battery to reach a suitable temperature for fast charging. This targeted warming is called preconditioning.

If you only drive a few minutes through the city and then plug in, the battery usually arrives cold. This is even more true if the car has been parked outside. As a result, EV charging in winter can be significantly slower, even though everything is working as it should.

Tips for Faster Charging in Winter

A few practical steps can often improve charging power noticeably, without changing anything at the charger.

• Most vehicles provide features to condition the battery before departing → Check your vehicle settings to see if you can pre-condition the battery before you set off
• Most vehicles pre-condition automatically when the route is set for fast charging → Use in-car navigation to the charging location 
• Pre-conditioning takes time → Plan fast-charging for longer trips
• Ideally charge after you have been driving, not right after starting → Use destination chargers instead of en-route chargers 
• Watch the charging curve: in sub-zero temperatures, power often increases after a few minutes as the battery warms up → If none of the above is applicable, hang in there, it might get better

What this Means for JOLT Ultra-fast Chargers

Our JOLT ultra-fast chargers provide the power shown at the station. How much of that power actually flows, however, is determined by your EV. If the battery is cold, the vehicle requests fewer kW to protect itself. That’s not a charger fault. It’s a safety concept built into the vehicle by the manufacturer.

So if you charge your EV in winter, it’s worth keeping in mind that the session will need to be planned in advance or may take a bit longer. This is (at the moment) the way it is.