On the Charge

eeVeeWorld aims to provide you with the tools necessary to learn about the intricacies of the ever-growing electric vehicle scene. There's a whole new world out there when it comes to EV's.

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Driving the future

Wouldn't you like to be able to do all your daily driving without ever having to visit a petrol station? Well that's the reality for most people who drive electric vehicles. Electric vehicles or EVs are becoming more popular. They're convenient, they're quiet, they keep our air clean and for most of the short distance driving we do, they're the safest way to get from point A to point B safely, reliably and comfortably.

The average car journey distance in the UK is just 8.4 miles*. On a cost per mile basis a fully electric car could cost you a quarter or less than what it would for a traditional petrol or diesel car. Fully electric cars are designed to be as efficient as possible and there are generally 3 main components powering the vehicle; the on-board charger, inverter and motor. This means there is far less wear and tear on the car and little stress on the motor, with fewer moving parts susceptible to damage. All this means you’ll need a lot less servicing and the running and repair costs are minimal.

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At eeVeeWorld, we hope you'll find all the information you need to make an informed decision. By 2030 the UK government has announced plans to ban the sale of any new, purely fossil-fuelled vehicles. From 2035 all new cars sold will have to be solely battery or hydrogen cell-powered.

EV driving isn't just about cars. There's a whole new world of associated terminology and gadgets such as chargers, tariffs, apps and much more. Do you understand the difference between kW and kWh? How about miles/kWh or kWh/100 miles? CCS, AC and CHAdeMO connectors? Type 1 and Type 2 plugs? Slow, fast and rapid charging? Check out our forums where you can ask questions and discuss the issues.

road network

EV Owners Survival Guide

So you have decided to take the plunge, ditch the Internal Combustion Engine (ICE) car and go full Battery Electric Vehicle (BEV). Not Plug-In Hybrid (PHEV) or Mild Hybrid (MHEV) or even just plain old Hybrid. Whoa... too many new names and abbreviations?

Don't worry, we'll do our best to guide you through this new world of Electric Vehicles (EV). Whilst EVs are still just cars that you use to get you from A to B comfortably, there are some basics you will need to understand and appreciate before you embark on your new adventure.

Here at eeVeeWorld, we will concentrate almost exclusively on BEVs. Whilst Hybrids do have a battery for some traction power, ultimately, they still have a traditional petrol or diesel engine which can take over after the limited range of the battery is depleted. Driving a BEV, you don't have that fall-back but almost certainly you will have much more range.

With the current pandemic, many car dealerships have reduced the amount of time, if at all, you need to spend with them to purchase your new car. If it's an EV you're buying or have just bought, there is a likelihood that you have had minimal instruction on the differences from driving a traditional ICE car.

Sure, you can jump in, switch on and go... and no doubt that will have been demonstrated and most likely tried out during your test drive. However, the first real test of your abilities and knowledge will probably come when you need to charge it for the first time.

We are still amazed at the number of times we have come across new EV owners wondering why their car is charging so slowly as they plug in the Type 2 AC plug when there's a much faster choice of charging with a CCS plug at the same charger. Some EV owners have no idea what capacity or speed their car can charge at. Can an EV with a 3 phase, 22kW on-board charger (OBC), charge faster than one with a single-phase 7kW OBC? What is the maximum charge possible from a 350kW Rapid charger? The combination of questions is endless.

Again, we intend to clarify much of this here at eeVeeWorld. You will find guides and articles as well as links to many other websites that have all the information you need to survive in the EV world. For the time being, let us clarify why we intend to only concentrate on pure BEVs.

A Hybrid, MHEV or PHEV is still, for all intents and purposes, an ICE car with some small EV benefits. It doesn't matter if your motivation for EVs is environmental, financial or technical. You still have a choice of how you power the motion of your car. The electric range or assistance is only ever going to be a fraction of that available for ICE range.

For clarification, an MHEV or Self-charging hybrid usually refers to one that cannot be driven in electric-only mode, but which has an upgraded battery and electrical system. The primary purpose of adding mild hybridisation is to increase efficiency by allowing the vehicle to achieve some regenerative braking when slowing down and to use the additional power source to assist with acceleration and other electrical loads in the vehicle.

A plug-in hybrid electric vehicle (PHEV) is quite simply a hybrid car you can 'plug in', meaning the battery can be charged from an electric outlet such as a public charge point or even a three-pin socket in your garage.
Plug-in hybrids can travel further using only electric power than conventional hybrids, although not as far as pure electric cars (BEVs). For example, most PHEVs have an electric-only range of around 30 to 40 miles.

What this means is that, if you can charge your car at home or work, for example, and have a commute of around 30 miles or less, you’ll be able to run a PHEV on electricity most of the time, saving you money on refuelling. However, if you need to complete a longer journey and cover more miles, the petrol/diesel engine is there and can be refuelled as needed, just like an ICE car.

Charging Point Speeds

Slow charging
AC 3 pin plug and cable

Slow charging (2-3.6kW) by plugging into your household sockets or a dedicated 16 amp socket is almost like trickle charging an EV. For example, at 230v AC at 10 Amp, you would typically charge at 2.3kW. If you want to add, say 30kWh to your 50kWh battery (20% to 80% example charge), that would take around 13 hours.

For those who have the time, or only drive a few miles a day, slow charging whilst your car is parked is very common. At home, you might be able to access cheap electricity rates overnight, but you won’t take full advantage because you would not get much energy into your car using this method.

Fast charging
AC Fast charging

Fast charging (7-22kW) reduces charge times by increasing the current up to around 32 Amps (7 kW).

While not all-electric vehicles can accept a fast charge at 32 amps, most can be connected to them (with the right connector) and will draw either 16 or 32 amps depending on their capability.

For example, at 230v AC and 32 Amps, you would typically charge at 7.2kW. If you want to add, say 30kWh to your 50kWh battery (20% to 80% example charge), that would take around 4 - 4½ hours.

This is typical of the speed most people use to charge their EVs. It will depend on the built-in charger of the EV. If your on-board charger is 7.2kW and you plug into a 22kW charging point, your car will only draw up to 7.2kW.

Rapid charging
DC Rapid charging

Rapid chargers (43-350kW) usually supply an electric vehicle directly with direct current (DC) from a dedicated charging unit using a tethered cable equipped with a non-removable connector.

With rapid DC charging, the cars Battery Management System (BMS) controls the actual charging speed. For example, if your car can take up to 100kW and you want to add, say 30kWh to your 50kWh battery (20% to 80% example charge) that would take around 20 minutes. Regardless, most cars won't charge at their maximum rate.

These chargers are often found at motorway service areas or on primary driving routes. These chargers are also the most expensive for the charging networks to install because of the hardware and grid connections.

How long should an electric car's battery last?

It's the vehicles most critical - and expensive - component. Fortunately, it should be able to go the distance.

In many ways, an electric vehicle is mechanically simpler than a conventionally powered vehicle. There are far less moving parts in an electric motor than a petrol or diesel engine. An electric car uses only a single-speed transmission and EVs avoid over two-dozen common automotive components that will eventually fail and need replacing.

Battery life is one of the biggest worries potential buyers have when considering an electric car. Like any battery, including the one in your mobile phone or laptop, the batteries in electric cars will lose some of their capacity over extended use. However, EV batteries are not a disposable item and will outlive a typical combustion engine car.

The good news is that car manufacturers know buyers worry about battery life, so many offer much longer warranties on high-voltage batteries than they do on the rest of the car. However, while an electric car’s battery pack will eventually lose its ability to hold a full charge, rest assured that it’s not likely to fail altogether, but rather lose its capacity gradually over time.

BATTERY BASICS

The lithium-ion battery packs used in electric cars are similar to those used in cell phones and laptop computers, only they are much larger. They are far different from the heavy lead-acid batteries used in conventional cars and have a higher energy density than rechargeable nickel-metal hydride batteries. They are also less prone than other battery types to lose their charge when not being used. EV battery packs generally contain a series of connected individual cells, perhaps several hundred of them depending on the model, instead of a single massive unit.

An electric car’s battery capacity is expressed in terms of kilowatt-hours, which is abbreviated as kWh. More is better here. Choosing an EV with a higher kWh rating is like buying a car that comes with a larger fuel tank in that you’ll be able to drive for more miles before needing a “fill up.” Be aware though, an electric car’s battery management system prevents the battery from either becoming 100% fully charged or 100% discharged to preserve its efficiency and extend its usable life.

Driving at higher sustained speeds will tend to use more battery power than will stop-and-go around town use. That’s counter-intuitive for many people as it’s the opposite of how an internal combustion engine (ICE) car works, which uses less fuel while cruising at motorway speeds than in traffic around town.

Extreme weather, very hot or very cold, can hamper both a battery’s performance and its ability to accept a charge. The additional heating or cooling needed for passenger comfort requires more energy than more moderate temperatures would.

Like humans, batteries also like to be comfortable and function best at moderate temperatures (although they’re a bit more cold-friendly and tolerate a wider temperature range). An EV’s on-board thermal management system is designed to draw energy to warm or cool the vehicle’s battery, as needed, to ensure it operates in that ideal range. Therefore, the car is working to heat/cool both the occupants and the batteries in cold or hot conditions.

Cold batteries also have greater resistance to charging and do not hold a charge as well. Importantly, extreme temperatures, hot and cold, can hamper both a battery’s performance and its ability to accept a charge.

BATTERY LONGEVITY

Typically, battery warranty coverage is 8 years or 100,000 miles, but this will vary by manufacturer and country.

Battery degradation is a natural process that permanently reduces the amount of energy a battery can store or the amount of power it can deliver. The batteries in EVs can generally deliver more power than the powertrain components can handle. As a result, power degradation is rarely observable in EVs and only the loss of the battery's ability to store energy matters.

Whilst some electric car buyers take out extended warranties to salve any fears of excess battery depletion, it’s not particularly necessary. Be aware, however, that some car manufacturers only cover the battery pack against a complete loss of its ability to hold a charge, which would be extremely rare. Others, including BMW, Nissan, Tesla (Model 3) and Volkswagen will replace the pack if it falls to a specified capacity percentage while under warranty, which is usually 60%-70%.

But how long would it be before an electric car loses its ability to hold a full charge? As mentioned above, while an electric vehicle’s battery pack will tend to degrade slightly with each charge and discharge cycle, it’s an extremely gradual process. For example, according to data compiled by the organization Plug In America, the battery pack in a Tesla Model S will only lose around 5% of its original capacity over the first 50,000 miles, with the rate of depletion actually slowing down from there. In a recent Tesla discussion thread on Reddit, most of those owning a Model S reported losing only a few percentage points of the car’s initial battery capacity after several years of use.

On the downside, electric cars kept in the hottest climates can be expected to lose battery capacity a bit quicker than those living in more temperate areas. Extreme heat is the enemy of lithium-ion chemistry, which is why many electric cars come with liquid-cooled battery packs. Also, older electric cars having relatively short operating ranges may suffer quicker deterioration. That’s because draining most or all of a battery’s charge regularly tends to cut into its capacity more quickly over time. That’s far less of an issue with today’s longer-range models that are typically driven for a fraction of their available capacity daily and are merely “topped off” at night.

Excessive use of public Rapid charging stations (they can bring an EV from 20% up to 80% of its capacity in as little as 25 minutes) can also take a toll on a battery's long-term performance. That’s because the faster an electric car is charged, the hotter it becomes and, again, that’s not battery friendly.

The bottom line here is that if it’s properly cared for, an electric car’s battery pack should last for well over 100,000 miles before its range becomes restricted. Consumer Reports estimates the average EV battery pack’s lifespan to be at around 200,000 miles, which is nearly 17 years of use if driven 12,000 miles per year.

Looking forward, Tesla says it’s working on technology that would enable its electric car batteries to last for as many as one million miles, which is likely more than the rest of the car might hold up. Now that’s a lifetime-of-the-vehicle component.

Home Charging

One of the most attractive elements of owning an EV is that you can always have a full or nearly full 'tank' when you leave home in the morning. If you are about to buy an electric vehicle or already own one, a home charging unit offers extra convenience when charging your car.

Electric vehicles have a charger built-in. What you are purchasing is a means of connecting that built-in charger to your mains AC power supply.

In the UK, most homes are supplied with single-phase electricity. Electric vehicle chargers draw considerable power when compared to most other electrical items in the home which mean you will need an electrician to check that your electrical system can handle anything more than a 10 amp supply.

Finding the right home charger can be tricky. Things to consider include rate of charge, reliability, looks, size, with or without cable, software support from the manufacturer, the list goes on.

For those with a driveway, garage or any other form of off-street parking, the obvious solution is to charge at home. 

Charging / Types of charging

EV Charging for Dummies

When you enter into the world of electric vehicles, there's a whole new language you need to understand. If you're coming from the Internal Combustion Engine (ICE) era, gone are your MPG or L/100 Miles. You are now dealing with electricity.

It is important to distinguish between the two different types of charging, AC and DC, that almost all modern EVs are capable of.

AC charging you do at home, at work or on any public "fast" charging point. Every electric car can accept AC grid electricity and converts it through the on-board charger to DC. However, electric cars differ in terms of how much AC power they can take.

For example, the Audi Q4 e-tron Sportsback has an 11kW maximum AC charging rate. The Hyundai Kona Electric has a 7.2kW maximum AC charging rate. You might be charging your car at a 22kW AC charger – and be expecting a very fast charge – but only get 7kW or 11kW of power out of the ChargePoint due to your car’s limited on-board capabilities

When it comes to DC charging, you do this at a "rapid" charger. These convert high voltage AC to DC and supply it directly to the battery, bypassing the on-board charger. As the name implies, they charge much faster than AC. The Audi Q4 e-tron can charge at a maximum 125kW DC whilst the Hyundai Kona can only "rapid" charge at up to 77kW DC and is dependent on the cars Battery Management System.

Rapid chargers will usually supply anything between 43kW, 50kW, 100kW, 150kW and higher. There are very few electric cars at the moment that can charge above 250kW. Many older 50kW DC rapid chargers are now being replaced with 150kW and higher DC chargers.

You will often hear about how many miles an hour can be added to the battery's range concerning how long it will take to recharge. However, all this depends on many factors.

The problem is that EVs don’t all go the same distance on a given amount of electricity. The distance you can go will also depend on many things including the weather, your driving habits, how much you use the air conditioning or heater and other factors. Whilst one EV might go 2.5 miles on a kilowatt-hour (kWh), another might go twice that distance. So, even though you may learn exactly how far your EV can go on a kilowatt-hour of electricity, that number could be totally different for someone else's EV.

What this means is that there is no correct and consistent way to say how many miles of range a given charger can deliver per hour of charging time. It is better just to learn the units.

Types of charging

Distinguish between the types of charging

Charging / Learning the units

Learning the Units

A good way to understand electricity is through liquid metaphors.

A kilowatt, denoted kW, is a rate of energy flow. It is like the litres per minute that a water hose or pump can deliver.

A kilowatt-hour, denoted kWh, is a quantity of electricity, like a litre. A bigger battery pack with a higher number of kWh will hold more electricity, just as a bigger fuel tank will hold more litres of fuel.

Now let’s put them together. If you were to run a 1-kilowatt generator (or EV charging station) for 1 hour, it will deliver 1 kilowatt-hour of electricity. (1 kilowatt multiplied by 1 hour equals 1 kilowatt-hour.)

If you plug your EV into a 50 kW charging station, and it runs at full power for one hour, how much energy would it pump into your car's battery? That’s right: 50 kWh because 50 kW multiplied by 1 hour equals 50 kWh.

Learning the units

The world of wiggly amps

Charging / Speed of charging

Charging Station Power Rating

The rate of power that EVs actually get while charging varies depending on how full the battery is. Starting from a low state of charge (SoC), a battery will charge at the maximum rate that the vehicles Battery Management System (BMS) will allow. As the battery fills up, it will slow down the rate of charging until it’s down to a trickle when the battery is almost full. So, it is unlikely that you would get a full 50kW of power continuously for an hour as in this example. But that’s a technical nuance that you will understand as you become accustomed to charging your vehicle.

Speed of charging

Slow, fast or rapid?

Charging / Charging stations

EV Charging Stations

If you just plug an EV straight into a standard UK AC socket using an EVSE (Electric Vehicle Supply Equipment) cable and 3 pin plug, you’ll get about a 2.3kW rate of charge. That's because it will be limited to below 13Amps and most likely only 10Amps. So, 230volts multiplied by 10Amps gives 2,300Watts or 2.3kW.

If you get a home charging station to speed up charging your car, it will probably have a power rating somewhere between 3.6kW and 7.2kW because you will need either a 16Amp or 32Amp supply. Some homes and many businesses may have a 3 phase electrical supply which means they could have 11kW or 22kW charging stations although most EVs cannot take advantage of the higher power due to the limitation of their onboard or built-in charger.

If you use a DC 'rapid' charging station, it might deliver 43kW, 50kW, 150 kW or more.

As you can see, it’s important to understand how fast a charging station is, because the power it delivers might be 100 times or more, faster than just plugging your car into a wall socket.

Charging stations

Home, destination or rapid?

Charging / Batteries

EV Batteries

The 2020 Hyundai Kona for example, is available with a 64 kWh battery. Suppose you bought a 7 kW home charging station for it, and you started charging it with an empty battery (which you would likely never do) and charged it at full speed until it was full, it would take about 9.2 hours (64 kWh divided by 7 kW equals 9.2 hours).

How long would it take if you did the same thing, only you used a 50 kW rapid charger? Just over an hour and a quarter (64 kWh divided by 50 kW equals 1.3 hours).

Batteries

kW or kWh?

Charging / Range

EV Range

Now that you know how to understand charging stations and cars, the only thing left to learn is how to understand the range of your car.

Let's take the Audi Q4 e-tron as mentioned above. It might go around 3.3 miles on a kilowatt-hour of battery power. With a 77 kWh battery that is a range of 254 miles. Now let’s take the Hyundai Kona with a 64 kWh battery. If you drive it very efficiently under favourable conditions, it can probably go 4 miles on a kilowatt-hour. So what is its range? 64 kWh multiplied by 4 m/kWh equals 256 miles.

So, the Hyundai Kona with the 64 kWh battery pack can go just as far on a charge as an Audi Q4 e-tron which has a battery pack that is 20% bigger!

Now, let’s try one last test of your new knowledge, and figure out how much range you can get per minute of charging. We don't tend to charge above 80% state of charge (SoC) as the power drops off dramatically above this rate to preserve the battery.

Suppose you charged up the Audi Q4 e-tron with its 77 kWh battery pack at a 150 kW Rapid charger at the maximum rate from 10% to 80% SoC. It is actually limited to a maximum 125kW and the average power would be around 110 kW. How many miles of range could you get per minute of charging? Well, 110 kW multiplied by 1 hour is 110 kWh, divided by 60 minutes in an hour, equals 1.8 kWh delivered per minute of charging. Multiply that by 3.3 miles of range per kWh, and you get 6.05 miles of range per minute of charging or 363 miles per hour of charging.

Now let’s try the same example with the Hyundai Kona. The charger is the same but you'll be limited to 77 kW by the car which will equate to an average of around 64 kW charge. But the Kona can go 4 miles on a kWh. So 77 kWh divided by 60 minutes is 1.28 kWh delivered per minute of charging. Multiplied by 4 miles of range/kWh equals 5.12 miles of range per minute of charging or 307 miles per hour of charging.

You could also look at it as how many miles range can you add if you just 'top-up' for 20 minutes. The Audi would gain 121 miles of extra range whilst the Hyundai Kona would gain 102 miles extra range.

Now you see why the rate of the charge depends on the vehicle.

Hopefully, you now understand how to speak the EV language. Even if it is unfamiliar at first, try a few of these simple calculations—using only multiplication and division—and pretty soon you will be able to estimate your charging time and your range on a charge.

Below are some examples of EV models with their battery capacity and consumption rates.

Range

How far can you go?

Car charging and the differences explained...

Every EV comes with a built-in (on-board) charger. These built-in chargers handle the AC electric supply and convert it into DC energy for the main (High Voltage) battery via the Battery Management System (BMS). However, an EV can also be charged directly by DC which by-passes the built-in charger and is supplied directly to the battery via the BMS.

The main difference between these two methods is the speed or rate of charge. Typically, on-board AC chargers are rated either 3.7 kW, 7.2 kW, 11 kW or rarely 22 kW. What this means is that the charger cannot supply more than its rated charging capacity and subsequently, depending on the capacity of the battery, this will affect how long it takes to fully charge. Whilst the onboard charger may be capable of its designed speed, it will still depend on the capability of the EVSE to supply power at that rate.

EVSE stands for Electric Vehicle Supply Equipment and its function is to supply AC electric energy to the on-board charger. EVSEs are also known as EV charging stations, electric recharging points or just charging points.

For example, if you use a 3 pin EVSE (also known as a 'granny cable') to charge your car, these are normally restricted to 10 amps at 230 volts which will equate to 2.3 kW. Many people will want to know how many miles range can be added to their battery per hour of charging.

2.3 kW/hour of charging (2.3 kWh) will typically add around 3 to 5 miles range per hour of charging. To charge a 50 kW battery from 20% to 80% would take around 12½ hours. Not a problem if you have the time and can charge overnight or whilst at work. Although the on-board charger may be capable of charging at 3.7 kW or higher, it is restricted by the EVSE controlling the supply.

A typical home EVSE which is rated up to 32 amps and a supply rated for that will typically provide about 7.2 kW/hour of charging (7.2 kWh) which will add around 20-25 miles per hour of charging. To charge a 50 kW battery from 20% to 80% would take around 4¼ hours. For most people, this is all they will need.

For longer journeys which are beyond the fully charged range of the EV, you would typically use a Rapid DC charger. These range in output from 43 kW up to 350 kW. At the moment there are very few EVs that can utilize more than 250 kW output. However, the higher DC output of these chargers means that it takes much less time to top up.

If an EV can take up to, say, 100 kW DC charge, which would add around 20-25 miles per hour of charging. To top up a 50 kW battery from 20% to 80% would take around 4¼ hours.

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Overview of the Electric Vehicle Homecharge Scheme

The Electric Vehicle Homecharge Scheme is a grant that provides a 75% contribution to the cost of one chargepoint and its installation. A grant cap is set at £350 (including VAT) per installation. The main requirement is that a person owns, leases, or has ordered a qualifying vehicle and has dedicated off-street parking at their property. A person may apply for 2 chargepoints at the same property if they have 2 qualifying vehicles.

Find out more at Office for Low Emission Vehicles (OLEV)

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If you already own an EV or are thinking about getting your first one, we will try and provide you with the necessary knowledge to make the transition or continued use as easy and concern free as possible. The forum and other articles will hopefully guide you and stimulate you into expanding your knowledge of the future of driving.

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