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What charging questions should you consider if you've already got an EV?

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2 February 2022

If you’ve already got an EV and you’re relying on public charging points to fill the battery up, how could a home charger benefit you?
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EV being charged on driveway

How much will it cost you to charge at home rather than using public points?

The average EV usable battery size is 62.5 kWh, so we can use the formula of:

Electricity unit rate (enter as 0.189p) x battery size (62.5 kWh) = cost to fully charge: £11.81

This formula can be applied to any EV - you just need to make sure you’re using the right electricity unit rate and the correct battery size.

Electricity unit rate (UK average)Usable battery sizeCost to fully charge
Honda e28.3p28.5 kWh£8.06
Nissan Leaf28.3p37 kWh£10.47
Porsche Taycan GTS28.3p83.7 kWh£23.68
Mercedes EQS 450+28.3p107.8 kWh£30.50

Figures taken from https://ev-database.uk/

We can also work out the cost per mile by dividing the charging cost by the real-life distance the car can travel. The Honda e has a real-life distance of 105 miles on a full battery, so we would divide 5.38 by 105 to get a cost per mile of 0.05p. 

What's the best time to charge your car?

The best time to charge your car will be during off-peak hours if you get an EV-specific tariff. The costs listed above can come down even further if you sign up to a time-of-use energy tariff. These are designed to help energy customers save money by offering cheaper electricity at certain hours of the night (e.g. from 12am to 4am). Some energy suppliers offer as little as 4.5p per unit of electricity during these hours, though most cars will need longer than the cheaper time period to fully charge.

Nevertheless, we see how the overall charging costs come down with that lower unit rate:

Time-of-use electricity unit rate (example)Usable battery sizeCost to fully charge
Honda e4.5p28.5 kWh£1.28
Nissan Leaf4.5p37 kWh£1.66
Porsche Taycan GTS4.5p83.7 kWh£3.76
Mercedes EQS 450+4.5p107.8 kWh£4.85

Figures taken from https://ev-database.uk/

These time-of-use tariffs are often marketed specifically as EV tariffs to entice EV owners to sign up to them, and present the most affordable way to charge an electric car at home. The flipside, though, is that suppliers charge much more for “peak” electricity in order to make up the shortfall caused by the off-peak hours. You therefore have to be disciplined about your energy use and know exactly what your overall spend is likely to be.

How easy is it to get a home charger installed?

It’s easy to get a home charger installed as long as you have somewhere to house it - most people put theirs on the garage wall. Delays can come as a result of backlogs that the installer is experiencing as more people book their installations, or on the day when unforeseen issues arise in terms of structure or where the cables need to go.