Charging your EV with examples of charging times

Charging your EV examples of charging times

We have been looking at charging your electric vehicle, currently the infrastructure is at it beginnings, most governments have a plan to get this in place.

In the United Kingdom the Office for Low Emission Vehicles (OLEV committed £1bn from 2015 to 2020 to support Ultra Low Emission Vehicles (ULEVs) including battery and vehicle R&D, and grants for vehicles and charging infrastructure. 

ULEVs are also seen as an area for UK leadership in engineering expertise and manufacturing.

Business use of electric cars and vans will be a significant proportion of overall market growth. 

This with the acceleration of market segments such as taxis, buses and delivery vans, comes with its own particular charging needs which must be met for the market to succeed.

The above graphic shows a basic overview of home charging.

There are four different types of electric vehicle charging system referred to as “Modes”. These 4 modes are defined by the BS EN 61851-1 standard, while there are future plans for a wireless charging standard under the series BS EN 61980.

The EV industry is moving fast and product developments  constantly being updated. There are already systems that fall outside the strict definition of the specified modes but these definitions remain a good basis for understanding the core differences between systems.

Note on AC charging:

The vehicle being charged will charge at the lowest of a number of rates determined by:

• The chargepoint outlet power

• The power handling capacity ofthe cable connecting the charger to the vehicle

• The on-board charger in the vehicle

Typically it is the on-board charger in the vehicle that limits the charging rate. 

For example, a vehicle equipped with a 3.7kW on-board charger, when attached to a 22kW AC charge point, will only charge at 3.7kW. 

Rates and speed of charge:

With the development of faster charging technology and battery improvements charging times will be greatly reduced.

Looking at the below table with increased adoption of chargers in workplaces a truck delivering goods can be recharged to 80% within 15 minutes, which is feasible.

 The amount of charge required is the number of kWh you need to put into the battery which in most cases will be less than the full capacity of the battery even assuming it will be charged to 100.

Charge rate behaviour, the charge times for high power chargers are often quoted to 80% because this is where the performance advantage is gained and what they are designed to do in public use scenarios. This is because the battery’s ability to charge at a high rate diminishes as it gets nearer to full capacity.

It is widely accepted that over 80% of electric vehicle charging will take place at home and mostly overnight. This provides benefits not only to the consumer but also to the UK energy system as a whole. Opportunity for en route charging from workplace or public infrastructure is a smaller but just as important part of the picture, not least for PHEVs to maximise use of their battery-only mode.

To some extent, the installation of on street charge points has been motivated by the anticipation of drivers “range anxiety” which can be reduced by having a charge point on every street. However, many people believe this concern will naturally diminish as EV ownership grows without the need for an over-generous vehicle to charge point ratio. In order to provide confidence for drivers and deliver commercial longevity for the infrastructure, accessibility and carefully planned locations are probably more important considerations than total charge point numbers. Some vehicles are depot based which brings a different set of issues and opportunities.

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