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Does my electric vehicle weigh more after I have charged it?

An electric car might weigh a bit more after charging, but not all our readers agree

10 August 2022

Hand of man inserting a power cord into an electric car for charging ecofriendly vehicle on green landscape

SimonSkafar/Getty Images

Does my electric vehicle weigh more after I have charged it?

Alex McDowell
London, UK

According to Albert Einstein’s theory of special relativity, energy has mass. Through his equation E = mc2, we can deduce the mass of energy put into batteries.

The battery of a large Tesla holds 100 kilowatt hours, or 3.6 × 108 joules, hence the extra mass from charging it would be 4 × 10-9 kilograms. This is small compared with the mass of the car, which is typically more than 2000kg for a large Tesla.

Eric Kvaalen
Les Essarts-le-Roi, France

If you add 100kWh to…

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