Electric Fleet Charging
It's important to consider the solutions available for charging your electric vehicle fleet. You will need to support the needs of the fleet while managing any impacts on your facility infrastructure.
Electric vehicle fleet charging
Fleet charging can come in a number of forms. It typically reflects where the vehicle is parked for the longest durations:
- Overnight at the fleet yard, which allows access to the lowest energy costs
- At an employees home
- Out during the day
Choosing the right power output
Fleet managers often want to have the highest power output as the best solution for a busy fleet and to future proof. But a more powerful charge point is often not more efficient.
- Where vehicles have ample opportunity to charge overnight, a 7kW single-phase charge point may be adequate, without over stressing the available electrical connection.
- Fast charge points, typically 50kW output, are very effective when you need a fast turnaround of a vehicle. However these charge points require a large power supply and normally stop charging somewhere between 80 and 90%. This is to mitigate against the effects of high power charging on the battery.
An additional consideration is the impact your chosen charging solution will have on your facility Maximum Import Capacity (MIC). A higher MIC may increase the running costs of your facility.
This is the most common and universal method of charging vehicles. Even when a vehicle has the capability to charge at higher levels, it will still be able to charge from a single phase charge point. Within this category, 7.2kW is most common in business applications.
Lower outputs are normally only chosen where the electrical connection to the building is limited. Where a vehicle is available to charge for 10-12 hours overnight, there is potential to enable 300-400km before duties recommence in the morning.
As a rule of thumb, a three phase charger offers three time the output to its equivalent single phase unit. But the number of vehicles available in Ireland with three phase capability is currently very small.
It is not certain that this technology will gain any more acceptance in the future as DC technologies are most prominent at the upper end of the charging scale. Three phase chargers will deliver up to 22kW, however it is worth remembering that an 11kW charge point will only deliver 3.6kW to a single phase vehicle.
DC charging is normally the most powerful. It is commonly configured for up to 50kW, however higher power ratings are now available. The economics of installing a higher power charge point is not limited to the cost of the charge point, but also to the additional connection costs and standing charges for the electricity supply.
The benefit of DC fast charging is that you have the potential to turn around a vehicle in a short time. DC charging can be delivered with output levels of circa 20kW, this may be an option when you need to turn a number of vehicles around in a short time window. The available electrical supply can be shared amongst a number of lower power units.
Charging level comparison
To compare the benefits of one charge point power level against another, think in terms of driving distance rather than percentage of charge. 100km is constant regardless of battery size, while 80% battery state of charge in a 30kWh battery can do much less work than the same percentage in a 60kWh battery. The table below gives an indication of what you can expect.
|Power||Charge type||Voltage||Current rating||Charging time for 100km driving range|
|3.6kW||Single Phase AC||230V||16 Amps||6-8 hours|
|7.2kW||Single Phase AC||230V||32 Amps||3-4 hours|
|11kW||Three Phase AC||400V||16 Amps||2-3 hours|
|22kW||Three Phase AC||400V||32 Amps||1-2 hours|
|50kW||DC||~400V (DC)||~125 Amps||20-30 minutes|
AC charging connectors
European standards have now been adopted for EV charging connectors. In the category of AC charging, sockets on all home and business chargers are the same, while the connector on the vehicle side may differ. Vehicles are normally supplied with an AC charging cable, in which case the charge point side of the cable is a standard cable known as Type 2.
AC charge points are sometimes offered with the cable tethered to the charge point. This can have its advantages as the driver doesn’t need to take the charging cable in and out of the vehicle storage. It is important to consider that as the vehicle side connector can differ over the older and more recent generations, vehicles with the older type of connector will not be able to charge on newer charge points and vice versa.
DC charging connectors
Connectors used for DC charging are covered by European standards and regulation. The first vehicles delivered with DC charging adopted a specification known as CHAdeMO. As the industry evolved Combined Charging System (CCS), also known as Combo, was adopted as a European standard. CCS is delivered in the majority of the vehicles on the market today.
Public fast charge points are normally equipped with both connectors, allowing any generation of vehicle to charge. If considering DC charging for your private fleet, it is wise to equip the charge point with both connectors. As the power electronics stays the same, the additional cost should be small and the equipment more versatile.
Installing a charging point
Optimise the setup with careful planning. These are the steps involved to install a charge point:
- Identify the location
- Determine the power of the charge point(s)
- Identify electrical connection point
- Procure charge point(s)
- Route cable to the charge point(s)
- Install charge point
- Connect electrical supply at both ends
Charging facilities for staff and customers
Many organisations are recognising the introduction of electric vehicles amongst commuting staff. Similarly they may notice that customers are arriving to their premises in an EV. This commonly leads to requests for charge points for use by privately owned, non-fleet vehicles.
Charging facilities for staff or customers can be integrated with existing fleet charge points or provided via a third party service. It is possible to separately record energy consumption and recover the cost from the user.
Customer parking is often separate to company vehicle parking, reducing the practicality of using existing charge points. Additional points may be connected to the same management system as the fleet chargers or may be connected to a third party system. When connecting to third party access systems, the user will be charged a fee for the service by the operator. Energy costs are reimbursed to the host site.