Charging your business’s electric vehicles

To work our how long it will take to charge your EV using an alternating current (AC) charger, such as 7kW or 22kW fast charger, use this equation:   

Charge time (hours) = size of battery (kWh)/power of charger (kW)   

A 22kW charger charges three times faster than a 7kW charger. So, for example, a 22kW charger can charge a 50kWh battery in just over two hours. This would take seven hours with a 7kW charger.  

Unless you’re charging larger vans, trucks or buses, which all have batteries larger than 50kWh, you might not need to charge your batteries quickly.  

You can install much more rapid chargers at a depot if you want to, but they’re expensive and you generally don’t need them. Only a few vehicles (such as heavy commercial vehicles, vehicles with very large batteries, or those being shared between drivers with little downtime) will need to be charged using rapid chargers.

You can only use 22kW charging if your building has 400V three-phase electricity. This is supplied to a lot of commercial properties. Ask your electricity supplier if you have a three-phase supply.  

EVs have on-board devices that limit charging speed from AC chargers. In other words, the speed your vehicle can charge at is dictated by the vehicle and not the power output of the charger.

For example, if your vehicle has a charge limit from an AC charger of 7kWh you will only be able to charge at that speed regardless of whether you use a 7kWh charger or a 22kWh charger.

Most new vehicles’ on-board chargers accept up to 11kWh of charge each hour. These vehicles will charge 1.5 times faster if you’re using a 22kW charger rather than a 7kW charger. 

This depends on your tariff. Currently, the average price of commercial electricity is 21.56p per kWh. [Accurate as of December 2022] 

You can: 

1. Use smart charging systems that only charge when electricity prices are cheaper.  
2. Install solar panels and generate your own free electricity to charge your vehicles.  

Costs are for the full installation of a chargepoint and include the discount from using the UK Government’s workplace charging scheme. This gives up to 75% off the costs of chargepoints. All costs taken from Zap Map.

1. Apply for the electric vehicle infrastructure grant for staff and fleets. If you’re eligible, you can apply for up to five grants, each for a maximum of £15,000.  
2. Use wall-mounted charging points instead of charging posts, and position chargers closer to the mains electricity. Doing both of these things reduce the amount of digging needed to install charging infrastructure.  

Technically, while it’s possible for electric cars and vans to charge from a domestic three-point plug, manufacturers don’t recommend it. It’s slow and could cause electrical faults because they don’t have protection systems that chargepoints have. Instead, your drivers should install an EV charging system at home. 

Most home charging systems are either 3kW or 7kW.  

For AC chargers such as the 3kW and 7kW chargers, you can calculate charging time using this equation:  

Charge time (hours) = size of battery (kWh)/power of charger (kW) 

You may find that 3kW chargers would be too slow if the vehicles don’t have a lot of down time overnight. For example, a 50kWh battery would take over 16 hours to charge with a 3kW charger. 

The cost of electricity is variable. Current standard rates are around 34p per kWh. At this rate, it would cost £17 to fully charge a 50kWh battery. Make sure you check average electricity costs.

You should encourage your drivers to charge their vehicles on a ‘time of use’ tariff. These encourage customers to use energy at off-peak times.

Overnight electricity is normally off-peak. Average off-peak prices are 20p per kWh (based on Energy Saving Trust data, accurate as of October 2022). Charging a 50kWh battery off-peak would cost £10. This is a £7 cost saving compared to using standard electricity rates. To get the most out of these low costs, drivers should install smart charging systems that automatically set vehicles to charge at off-peak times.

A 3kW charging system costs £250–£500 and a 7kW charging system is around £450–£800.

Installation costs will vary depending on drivers’ homes. For example, some drivers might need to have long trenches dug to install wires, and this would increase costs. Drivers who rent their home could get 75% off the cost of installing a charging system. 

Most rapid chargers are 50kW DC chargers. These can charge 60kWh batteries to 80% in around 30 minutes.  

Using rapid charging is the most expensive way to charge EVs, currently costing around 20p per mile.

(Accurate as of January 2023, RAC Charge Watch)

You pay for most public chargepoints through a smartphone app or radio-frequency identification (RFID) card. You usually need to use a different app or RFID card for each chargepoint operator, but charge cards solve this problem. Charge cards give businesses access to networks run by different chargepoint operators. They also offer free-at-the-point-of-use charging, so the business pays for all the costs and not the driver.

Most on-street public chargepoints in residential areas are slow 3kW AC chargers, but they may find some 5kW or 7kW options. These chargepoints are compatible with almost all EVs, but drivers should bring their own cables when charging, as they aren’t usually provided. 

The 3kW chargers are slower than other options, so it’s important that drivers plan in enough time to charge their vehicles. They can use the equation below:

Charge time (hours) = size of battery (kWh)/power of charger (kW) 

Using a 3kW charger, a 40kWh battery takes just over 13 hours to fully charge. If your driver starts work at 9am, they would have to start charging their vehicle before 8pm the night before. 

The cheapest public charging option is 3kW on-street charging. Use Zap-Map’s calculator to estimate on-street charging costs for your EV or EV fleet.  

Local authorities can install them through the on-street residential chargepoint scheme (ORCS) and the local electric vehicle infrastructure (LEVI) scheme. If your local authority has signed up to either scheme, ask for their support in providing the charging infrastructure for your business. If they haven’t signed up, you can ask them to apply.