Is it free to charge mobiles while driving?

15 April 2014



For some time I have been trying to find an answer to my question; if I charge my mobile devices at home it costs me money (power bills). If I recharge whilst driving, does this cost money?

Thank you

Alan McNamara


Well, for a start, it depends if he's paying for the petrol because basically, that's what it boils down to. So, when you're driving along, any electrical item you run inside your car, is running off the alternator or the battery, and the battery is recharged using your petrol when you're driving, the alternator uses the petrol when you're driving. So, when you plug stuff in, there is more drag in a nutshell and your fuel consumption is affected accordingly. However, a mobile phone costs about 50 p to charge over the entire course of the year, so I really wouldn't worry about it. If he wants to save on his electricity costs, he should probably look at things in his home like his plasma TV perhaps which might be 100 pounds over the course of the year, maybe something like a washer/dryer. The dryer part of a washer/dryer is going to cost many dozens of pounds a year and stuff like that. I think my favourite one is a microwave oven. So, the clock on a microwave oven uses more electricity over the course of his lifetime than cooking food does. So, if you want your microwave oven to cost the least amount of money, don't use it as a clock. Just turn it on when you want to use it.


On a related matter, in the winter or when it is cold, if the device or phone is then used inside (the car or a home, say) the energy dissipated will generally be converted into heat. That means that in order to achieve a comfortable temperature less energy needs introduced by other means (the car's heating system, or home radiators etc.). In such cases you benefit from the energy consumed twice so to speak, just as you do when cooking for example. The heat, firstly, cooks the food and, secondly, disseminates into the home (excluding the effects here of any exothermic or endothermic chemical reactions taking place during cooking). So basically, when it is cold, when you would require artificial heating anyway, charging your phone costs nothing. Correct me if I am wrong.

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