Slow fast charging usually means the vehicle, battery conditions or available station power is limiting the session. A 300 kW label is not a promise that your car will receive 300 kW. Compare the observed power with your model’s expected charging curve at the same battery level before deciding that the charger is faulty.

First check whether your expectation is realistic

Look up the exact model and battery version. Peak charging power may only be reached briefly. The useful comparison is average power across your intended charging window, such as 15 to 70 percent, rather than the highest number in a brochure.

Vehicle characteristics, temperature and battery level all affect charging speed. A session starting with a nearly full battery cannot be compared fairly with one starting much lower. Compare similar starting conditions before concluding that a charger is underperforming.

Check the battery level and temperature

At high state of charge, the battery-management system typically reduces power. If you only need enough energy to reach the next stop, waiting for the final few percent may not be useful. Our guide to 80 versus 100 percent explains how to choose a target.

A cold or very hot battery may also accept less power. If the car supports battery preconditioning for fast charging, follow its manual. Cabin heating is not proof that the high-voltage battery is ready. Likewise, selecting a charger in an external navigation app does not guarantee that the car has started preconditioning.

Check the station without repeatedly restarting

Confirm that you selected a DC connector with suitable power, not an adjacent AC socket. Read any station message about power limits. Some installations share capacity across connectors or cabinets, so another session can affect yours. A site may also temporarily reduce output because of a technical constraint.

A quick observation log

Write down arrival battery level, outside temperature, whether preconditioning ran, charger ID and power after the initial start phase. Note whether power changes when another car starts or leaves. This gives support something concrete to investigate and prevents a guess based on one momentary reading.

When does changing chargers help?

Changing can help if the current connector reports a fault or has insufficient available power. It is less likely to help if the vehicle is already near its expected limit or the battery needs conditioning. Consider the time required to stop, reconnect and authorise again, plus possible new session fees.

For illustration, supplying a remaining 15 kWh at an average 50 kW takes 18 minutes. At 100 kW it takes nine minutes. If switching consumes ten minutes, the higher power would not save time in this simplified example. Real power varies; use this calculation as a decision aid, not a prediction.

When should you contact support?

Contact the station operator for a displayed fault, unusual connector behaviour or persistent low station output. If the same problem repeats at independent working sites under comparable conditions, contact the vehicle manufacturer with your log. Do not open charging equipment or try to bypass thermal or safety limits.

If the session never began, follow the separate start-failure checklist. For the underlying units and connection types, read AC, DC and HPC explained. Solving the right problem is faster than repeatedly chasing the biggest number on a charger.

Put the checklist into practice with StromNow

Use StromNow to find charging points, review prices and plan a suitable stop. Check the station details before connecting and keep your next charging decision in one app. Explore StromNow and download the app.

Editorial review: 5 September 2026. Check current station conditions before charging.