EV Charging Basic

EV Charging Basic Things to Learn

Charging is not a new technology. It is widely used in cell phones, gadgets, laptops and more. Nowadays, it is widely used in the vehicle industry. The conventional way of powering our cars is through petroleum products (gasoline or diesel). However, with the advancement of technologies, cars are now being powered by electricity. 

Common Terms Used in EV Charging

EVSE

This refers to electric vehicle supply equipment. In layman’s term, a charging station.

Slow Charger

This refers to chargers that take hours to fill a drain battery, for instance, the adapter given together with the car and the level 2 AC chargers.

Fast Charger

This is the term given to a charger that can fill a drain EV battery in less than an hour. This charger is a DC type. Currently the terms ultrafast or hyper fast are being used. These are adjectives used to describe a DC charger that can fill an EV battery in 30 minutes or less.

AC Charger

This is a type of charger that accepts AC voltage and outputs AC voltage. There is no voltage conversion involved. The AC charger will connect to the onboard charger of the vehicle. The actual charging is not really performed in the AC charger but inside the vehicle.

DC Charger

This is a type of charger that has AC input while the output is DC. There is a voltage conversion. DC chargers will not pass to the onboard charger of the electric vehicle anymore but direct to its battery pack.

CCS (1 and 2)

CCS1 and CCS2 refer to combine charging system type 1 and type 2. Type 1 is standard commonly used in North America while type 2 is used in the Europe. The vehicle side charging inlet can accept the AC J1772 connector or the CCS (DC) connector. Thus, it is called a combined system. CCS connectors are capable of high current and high voltage.

CHAdeMO

This is a charging connector originated from Japan and still commonly used in Japanese cars upon this writing. CHAdeMO charging cable usually offering up to 200A and 600V making it inferior to the CCS charging cables.

Tesla

Tesla charging connector is very familiar in the US. It is own proprietary of Tesla.

NACS

Stands for North American Charging Standard. It is standardized as SAE J3400 and known as the Tesla charging standard.

SOC

It is an abbreviation of state of charge. The state of charge is the level of charge left to a battery.

Range

Range is the distance a charge can go. For instance, a range of 100 miles is the total distance the EV can go to totally deplete its charge.

kWhr

This is the unit used to describe the size or capacity of an EV battery. For instance, 80kWhr, 100kWhr and so on.

Charging Current

This is the actual current drawn from the EVSE.

AOC

Allowable output current. This is the limit of the EVSE.

Charger power

This is often referred to as the maximum power delivered by an EVSE.

Charging time

This is the time it takes to reach the desired battery charge level.

Charging Connector

This is the connector from the EVSE and going to attach to the EV inlet.

Charging inlet

This is a charging port in the EV

Types of EV Chargers or EVSE

Level 1

This often referred to a portable adaptor given together with the vehicle. You can charger your EV directly from your wall outlet with this thing. This is extremely a slow charger.

Level 2

It is still considered a slow charger but faster than the level 1 charger. Both level 1 and level 2 chargers are commonly referring as AC chargers. Level 2 EVSE offers wide current range from 30A to 70A.

Level 3

It is a fast charger. This type of charger is not installed at home but commonly seen in public places like parking areas, malls, convenient stores, stopovers and so on. They are also commonly known as DC chargers.

How EVSE Connects to EV?

AC Charger

AC charger is not really a charger as it is not doing the charging action but the onboard charger is. It is more fit to call it an adaptor. However, it is commonly known by many , so let us ride to that term. AC chager is could be the charger given free together with the EV or the AC charging stations in the malls, parkings, coffee shops and so on.

The charging gun or the charging connector or sometimes called the nozzle is inserted to the charging inlet or port in the vehicle side. If the vehicle inlet is a combo type (CCS), the charging gun is J1772.

The charging current will flow to the onboard charger in the vehicle before it will go to the battery. Onboard chargers are small thus it will take time to full the battery.

DC Charger

DC charger is a true charger. It is doing charging action. The charging current will no longer flow to the onboard charger in the EV but directly to the battery. With this, the EV can accept fast charging as it is not anymore limited by the small onboard charger. If the vehicle charging port is a combo type, the charging gun is CCS.

Can You Charge an EV to any EVSE?

The answer is no. First, you should know your EV. If it has a CCS port, then look for an EVSE that has CCS connector. On the other hand, if it has a CHAdeMO port, then look for a charging station with a CHAdeMO port as well.

However, nowadays there is lots of charging port adaptors that you can buy. You can use these things to charge your car to EVSEs with different charging connectors.

Very Important to Know in Using Charging Port Adaptors

Charging port adaptors are great invention. With it, you can charge your car to almost any charger. However, there are two issues associated with it. First is safety while the second one is efficiency.

Safety

The adapter is not perfectly design to marry a charging connector. It able to connect for sure but there may be little loose connection between the two. This loose connection will result to a resistance build up. With a higher resistance and a high current flowing into it, the connection will get hotter and hotter with time. Imagine if you are charging at home using an AC charger overnight and the connection is get hotter and hotter, it is scary. This may not be the case always but this is to warn everyone.

Efficiency

Since there is a resistance builds up in the connection, it will result to a voltage drop. With the amount of current flowing, the voltage drop will result to a power loss. Power loss with respect to time is an energy loss. It is a wasted energy; not utilize by your car but you still need to pay for it.

How long does a Car Battery Get Full?

Each EV specifies the time to reach a certain state of charge. Furthermore, the EV dashboard is fully equipped with this information. For instance the Hyundai Ionic 6, it can reach 80% charge from 10% SOC within 18 minutes if charged to a 350kW charger. I took this information from Hyundai itself (refer to below snapshot). Hyundai is releasing the Ionic 5 and 6 EVs which are simply great cars. Visit them at https://www.hyundai.com/worldwide/en/eco/ioniq6/technology.

This is taken from Hyundai

If the charging time information is not known and you need it for whatever reason then you can estimate it. If you know the battery capacity in kWhr and the charger power in kW, then the calculation will be like this:

Time to charge =  Battery Capacity (kWhr) / Charger Power (kW)

For instance in the Ionic6, the battery capacity is 77.4kWhr while the charger power is 350kW, then the time to charge from 10% to 80%  is

77.4kWhr x 0.7 / 350kWhr = 9.3 minutes

This is very way off to the Ionic 6 declared value. The reason of this is that Ionic 6 maximum plugin DC charging is only 233kW (based on Wikipedia data). This means that the 350kW EVSE will not be maximized.

Recalculation

77.4kWhr x 0.7 / 223kWhr = 14 minutes

The recalculated value is closer to the Ionic 6 declared value but not very exact. This is not accurate because the charging profile is not linear. During first few minutes of charging, the battery will demand high current, but it will start to ask lower current when the battery is near full charge.

What Range Can Get from a Charge?

EV dashboard will tell this information. Moreover, EV specs sheet is specifying this as well. For the Ionic 6, after 15 minute charging with ultra-fast charger, the range can get is 351 km. I refer this from Hyundai Ionic 6 specification sheet.

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