Introducing EVSE

So I’m here today in a supermarket car park  in Loughborough and why am I here? I’m here   to talk to you about electric vehicle supply  equipment or EVSE. Now EVSE basically refers   to the key components that you need to charge an  electric vehicle that consists of a chargepoint,   some sort of connector - traditionally a cable  - and then the receiver on the vehicle. Now   in some newer more innovative approaches  like wireless charging this cable’s done   away with but for the sake of this course we’re  going to focus on a more traditional design.  

Now the way that this all works is the  energy comes from the electricity network,   floats down into the chargepoint through the  cable into the car and charges the battery.   That flow tends to happen in just one direction  so from the network to the car and that’s called   unidirectional charging. Now you can also have  bi-directional charging which is where the battery   from the car also discharges back into either the  chargepoint or into the wider electricity network.   Now we’ll learn more about that through this  course but for now we’re going to focus on the   on a key aspect of uni-directional charging.  AC chargers tend to operate in three main   powers so you have 7 kilowatts, 22 kilowatts  or 43 kilowatts.

Now when we’re talking about   things like the power ratings this can feel like  a foreign language for anyone that’s not used to   an electric vehicle so we’ve got a useful rule  of thumb to try and make it easier for people  

to understand: in effect the power rating of a  chargepoint is equivalent to the amount of miles   range that you’ll add to the vehicle if you plug  in for 20 minutes - so on a seven kilowatt charger   if you’re plugged in for 20 minutes you’ll add  about seven miles of range; if you’re using a DC   charger that’s maybe 100 kilowatts then you’ll  be adding 100 miles range. Now DC chargers such   as this one operate at much higher powers and  that means much faster charging of your electric   vehicle.

DC tend to start around 50 kilowatts  and go up to around 450 kilowatts although   newer technologies are being developed every day  that can take that to higher and higher powers.   Now to put that into context a typical house in  the UK uses around eight kilowatt hours of energy   every day - if you plugged into a 450 kilowatt  charger you’d be using the same amount of energy   in just one minute.

So there are two main  connector types for DC: the first is ChAdeMO,  

now the CHAdeMO protocol was developed in Japan   which is where some of the first electric  vehicles such as this Nissan leaf were developed,   as a result CHAdeMO charging has become  prominent across the world however more recently

new standards have been  developed particularly in Europe   well where we now use the CCS charging system

the CCS charger uses the type 2 charger for AC and  combines it with some additional pins to enable   you to do DC charging as well. Now at the moment  what we see is this kind of setup where both   chargers are available because at the moment  we have cars on the road which use both types   however as the CCS standard becomes more prominent  all of the new cars coming into Europe will be   using this standard and it’s similar in the US  as a result over the years we’re expecting to see   the CHAdeMO protocol reducing and disappearing  from the European market while the CCS   protocol takes over.

So unfortunately charging  an electric car isn’t quite as simple as just   finding the highest power charger and plugging  it in every electric vehicle comes with an   inbuilt limit to the power that it can receive  and that’s different whether it’s AC or DC.   On AC that’s often around 7 or 11 kilowatts on  DC it can tend to be around 100 to 150 although   a lot of the newer electric vehicles have  much higher limits in essence what that means   is that even if you plug into a higher power  charger like a 300 kilowatt charger it will   still be limited by what the vehicle itself can  receive so in this case let’s say 100 kilowatts.

There’s also a second limit so if  you imagine on your on a standard   petrol car the range that you can drive  is limited by the size of your fuel tank   similarly the range you can drive an electric  vehicle is limited by the capacity of the battery.   So if you have a 30 kilowatt-hour battery  the maximum energy that you can put in is   going to be 30 kilowatt hours and that will  inherently limit the distance that you can drive.   So how do you decide what kind  of charger you need to use?   The key really is to understand how long you want  to be staying stationary in that location.

Let’s   say you arrive at a shopping centre like this and  you’re coming to your weekly shop you’ll probably   be in the supermarket for a good hour but if it’s  a supermarket like this you’ve got two options   you’ve got AC or DC. Now if your battery is quite  empty and so you want a full charge in that time   you’re going to want to make use of the DC  charging in this case a 50 kilowatt charger   and that will mean that your vehicle will be  filled in probably around 40 minutes to an hour.   By contrast if actually your battery is  relatively full and you just want to top up   then an AC charger will provide a lot less energy  over that time but will still meet what you need.   AC chargers are also great if you’re going  to be in a destination for a long time   so if you’re parked up at work or at a park and  ride traveling into town and your vehicle is   going to be there for most of the day then  AC charging will be exactly what you need   however if you’re intending to drive  down the motorway on your holidays   then you might want to have a bit  of a shorter stop along the way   in which case high powered DC charging is likely  what you need to keep you going on your journey.   Ultimately we’re in a position now where there’s  a right a wide selection of charging available   and so you can pick the right type of charging  for the time that you actually are stopping.