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Why is my car not charging at the rated speed?

Oppdatert: 16. sep. 2022

You have spent money on a new charger to use for your car, it is finally time to get started with home charging, and since you are using Electric Freeway SmartCharge you can see in real-time how your charger is delivering charge to your car. But your new 7,4 or 22 kWh charger is delivering 3,7 kWh charging.

Why is that?

There is more than one answer to this question, but the most obvious is that your house is delivering single phase power and you have a 16-amp fuse. In this scenario your maximum charging effect will be 3,7 kWh. If you know that your house has three-phase power delivered to your charger, then you need to check how your car is receiving power.

There are many differences between EV car models in how charge is received, and this is even more pronounced if you do DC fast charging, as then the charge curve comes into effect and your charge speed varies during the charge cycle.

So, what are the differences between single and three-phase power and how big of a difference does this and your fuse size do?

Most residential single unit homes built before 2000 will have single phase power supply and these buildings will mostly peak at 7,3 kWh charging speed with a 32-amp fuse. If you live in a multiuser dwelling or a newly built home, there is a good chance that you have three-phase power supply and can get up to 22 kWh charge speeds with a 32-amp fuse.

So, if your app is showing you a different charge number than you expected, check your car manual for how it receives charge from an AC charger. Then check if the building you are charging your car from can deliver the top speed that the charger is rated for.


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