Anyone weighing up an electric bike or scooter against the car or the bus tends to ask the same thing before they have even taken it for a spin: how much will all that charging add to the electricity bill? The answer is reassuring, because the electricity itself comes to just a few pence a charge, small enough to vanish into the bill. The expense that really matters, though, sits somewhere else entirely, and hardly anyone thinks to add it up.
A full charge costs just a few pence
An electric bike battery holds around 500Wh, or half a kilowatt hour; a scooter sits closer to 350Wh, and cargo bikes stretch to 700Wh. Working out the cost is simple: multiply the battery's capacity by the price you pay per kilowatt hour.
At the 26.11p per kWh set by the current Ofgem price cap, a full charge of an e-bike works out at roughly 15p, and a scooter costs even less. Allow for the 15% or so lost as heat while the charger does its work and the figure still only creeps up to about 15p for the bike and 11p for the scooter.
To get a feel for the scale, here is what the electricity costs by machine, for a daily commuter covering around 2,200 miles a year.
Want the figure for your own kit? Enter the battery size and how often you charge it each week.
Per mile, nothing on the road comes close
The fairest yardstick is the cost of the energy per mile, and here the e-bike has no real rival. It uses so little that topping up the battery is much like boiling the kettle a handful of times, which is why it pays to know what the rest of your appliances really cost to run.
- Electric bike: comfortably under a penny a mile once charging losses are counted in.
- Electric scooter: a shade more, because without pedalling the motor does all the work.
- Petrol car: around 14p a mile on fuel alone, before tax, insurance or servicing.
- Bus or tube: rarely under a couple of pounds a journey, with an annual travelcard well into the hundreds.
Across 2,200 miles that petrol adds up to roughly £300. A whole year of charging an e-bike costs less than a single tank of petrol buys you in a few hundred miles.
The battery, not the electricity, is the real cost
If the energy barely shows up on the bill, the expense that genuinely counts is replacing the battery. A lithium-ion pack keeps its performance for around 500 to 1,000 charge cycles, roughly 15,000 to 19,000 miles, after which its capacity fades and it needs swapping.
A replacement pack costs between £300 and £700, about ten times everything you will spend on electricity over the same period. Looking after it is where the real saving lies.
- Keep it between 30% and 70% for long spells rather than sitting at a full 100%.
- Charge it at room temperature, away from a freezing shed or direct sun.
- Always use the charger that came with it, matched to that battery.
- Never run it completely flat: draining to zero shortens the cells' life.
- Don't wait for a fault to check the cable and connectors.
The only way to be sure you are paying a fair rate for the little power it does need is to check today's electricity prices.
How to charge safely and make it last
Charging is cheap, but it should not be left to chance, especially in a flat or a shared building. A few simple habits keep it safe.
- Never charge the battery unattended, above all overnight.
- Skip cheap extension leads and power strips: under load for hours they overheat.
- Keep the battery away from anything flammable while it charges.
- Stop at once if you notice swelling, a smell or unusual heat, all signs of a cell in trouble.
Good to know: if you are on an Economy 7 or time-of-use tariff, set the charge for the cheap overnight window and you will shave an already tiny cost even further.