Subscription-based electric-car power increases banned in Europe

German car giant Mercedes-Benz is facing a legal battle in Europe over plans to offer a wifi-delivered power boost on some of its electric cars through a subscription that's in addition to the cost of the vehicle.

Mercedes-Benz currently allows owners to increase the performance of the EQE or EQS in North America for an annual payment of $US1200 ($AU1800).

However, Top Gear Netherlands has revealed European laws don't currently allow the practice.

For that money, owners of EQE350 4Matic and EQS450 4Matic models in the US get a time-limited performance boost of 45kW and 55kW respectively – an increase of about 20 per cent.

A spokesperson for Mercedes-Benz told Top Gear the ability to offer the feature in Europe depends on "legal matters".

Given BMW is currently able to offer heated seating on subscription, and Polestar is offering performance upgrades for its electric cars with a one-off fee – both of which are happening in Europe – it appears as if the predicament faced by Mercedes-Benz relates to power outputs.

The subscription trend has angered car buyers, but some auto giants are persevering as they try to create a new layer of profit – and ongoing revenue after the car is sold to the customer.

What has frustrated customers in particular is that, in many cases, the optional equipment or capability has already been fitted to the vehicle – but companies such as BMW and Polestar are still trying to charge extra for their use.