Towing an electric vehicle has been quite a hot topic recently, primarily because it has a big effect on a vehicles’ efficiency, halving it in some cases, and this makes some car buyers wary of switching to electric. But while towing certainly affects the range the most, Carwow’s Mat Watson wanted to see what effect mounting accessories, like a roof box or bike rack, or even just carrying five people has on efficiency.

The vehicle used for the series of tests is a Skoda Enyaq (check out our review) with the 201 bhp rear motor and the big 77 kWh battery pack (the Enyaq iV 80), currently one of Europe’s best electric crossovers. Its claimed WLTP range is 330 miles, or 318 miles if you opt for the larger 20-inch wheels like the ones fitted to this vehicle.

Mat begins the test by driving the vehicle with no trailer or accessories at 60 mph and 70 mph, then compares their difference in efficiency. He finds that at 60 mph, the vehicle predicts that it can do 231 miles (averaging 3.0 miles/kWh), while at 70 mph, that drops to around 200 miles (based on a displayed average consumption of 2.6 miles/kWh) - the calculations are done based on the vehicle’s displayed efficiency at the two speeds and its battery capacity.

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Carrying four passengers in the vehicle at 70 mph down to 2.5 miles/kWh, reducing the theoretical maximum range to 190 miles. Interestingly, putting a ski rack on the roof and having no passengers inside the vehicle is a considerably less efficient situation - average consumption increased to 2.1 miles/kWh, even though there’s not that much extra weight in the vehicle; it’s pretty clear in this instance that affecting the vehicle’s aerodynamics really dents the efficiency.

Carrying a bicycle rack and a single bike on it at 70 mph is marginally more efficient, 2.2 miles/kWh. Predictably, nothing even comes close to the drop in efficiency observed when the Enyaq tows the trailer, which is done at 60 mph, not 70 mph like the other tests, and efficiency really takes a dive to 1.3 miles/kWh.