Switching from carbon-based fuelled engines to EVs is a massive leap of faith. EV buyers should know factors such as air conditioning and weather affect range. Besides, how the car is driven and maintained during its lifetime is essential. The heart of the EV is its battery-management system(BMS) which makes a difference. Here’s all the critical information dissected for you.
The role of EVs in upcoming environmental woes will emerge over the years. Still, for buyers and admirers of such vehicles, the shift from fuel to electric is surrounded by fears of running out of charge in the middle of nowhere. They have questions on charging time, vehicle heating, battery life, speed, interoperability of chargers, and many more.
Above all, there is a personnel dilemma: Should the focus be on battery size, motor power, or speed? How are all these related? Besides, there are many related issues: What happens when an electric car is fitted with add-on electric bells and whistles? Will in-car cooling reduce the range?
There are quite a few surprises. Consider this: Internal combustion engine (ICE) vehicles provide better mileage on highways, but EVs will give a better range on congested roads and traffic jams. Yet, the running cost for EVs is about one-tenth of fuel-powered vehicles, which are more environmentally friendly.
How far can you travel?
The range of an EV depends upon overall usability, versatility, and charging infrastructure. These are essential factors when buying an EV. A good starting point is to consider the application:
1) Is it needed for intra-city driving, or will it hit the highways frequently? The range is less of an issue in the former case than in the latter, for which buyers should choose vehicles with at least a 400km range.
2) How far the vehicle can go is determined by the battery size (kiloWatt hour, or kWh) and electric motor power (kilowatts or kW). The bigger the battery, the longer the range, but it also makes the vehicle heavier and more expensive. Another main factor also is of motor that the battery powers. A 50kW motor running at maximum power will consume 50kWh of battery power in an hour, while a 100kW motor will drain it in 30 minutes.
3) The higher the kWh, the more powerful your vehicle is. But this also means that the range per kWh of the battery pack will be less. So, the energy consumption during acceleration is higher for a higher-power motor. It’s like comparing Ferrari versus a Volkswagen — the former has a much heavier engine and gives far less mileage (about 6 km/l) than the Volkswagen (around 20 km/l).
Managing range anxiety in EVs is far more stressful than running low on fuel in fuel-driven cars. The former will take a few hours to charge compared to a few minutes to fill up a fuel tank. Most car buyers are used to driving around with mileage usually much less than what manufacturers claim under “test” conditions. However, in the case of EVs, this can be quite an issue, as charging is not as quick as taking out cash from an ATM.
There are two metrics for describing battery capacity. Gross capacity, or total capacity, is the total energy a pack can theoretically hold. Net capacity, or usable capacity, is the energy the car can draw on to move.
How, where, and when should you drive?
If you are stuck in a traffic jam, unlike a petrol engine, an EV won’t consume much, just a tiny fraction to keep it on and run the infotainment system. While you don’t want to drive around on congested roads, the good thing is the EV battery will often recharge as you frequently brake on busy city roads.
The more you brake, the more range you get. That’s the principle on which hybrid vehicles are also being launched nowadays. They are trying to collect the lost energy when brakes are applied. This is known as Regenerative braking. In ICE vehicles, kinetic energy is converted into heat and is lost. In hybrids and EVs, this lost kinetic energy gives regenerative power to the battery.
While this gives some extra miles, the EV battery will drain faster when you are on a highway, unlike a conventional car fuel tank. You are consuming the battery without any regenerative charge as you aren’t braking often on the roads. So, within the city, you will get a better range.
Also, if you have the air conditioner in a hot place with sunshine for more than seven months a year, you get to a 25% lower range per charge than the manufacturer claims. So, a 400km range EV will give only 300km with the air conditioner running.
Also, you will likely get less range in summer than in winter. Battery life reduces as temperatures rise. That’s why if a manufacturer gives a warranty of eight years in India on the battery, it will be ten years in Europe for the exact vehicle.
Avoid the accessories:
EVs work on an all-electric, connected platform, so if extra electrical accessories are added, it complicates matters and increases power consumption. Fitting an electric sunroof, halogen lamps, or even unique horns can lead to considerable risks to performance. So Experts in the EV industry say, “The moment you tinker with anything electric, it will have an impact. The whole circuit loading of the car will change. Add-ons, if at all, have to be only via designated USB ports.”
Another concern for buyers has been charging infrastructure and the interoperability of chargers. Thankfully, the industry is consolidating towards two types of chargers for platforms less than 100 volts, including two, three, and entry-level four-wheelers. The charging protocol is GBT introduced first by the Chinese EV makers. For bigger batteries, there are two leading platforms – CCS2 and CHAdeMO. In general, bigger cars converge to the CCS2 platform also used by Audi e-Tron, Hyundai Kona, etc. So the same charging infrastructure can cater to vehicles from different manufacturers.
Most crucial part and heart of an EV @BMS
The battery management system BMS the brain of an EV to keep it all running smoothly and provide data on performance.
The fuel gauge, temperature, oil indicators, etc., in a conventional car provide information. In EVs, the BMS presents these as data points on the dashboard and helps make critical decisions automatically to ensure your and your vehicle’s safety. The primary function of the BMS includes battery protection and ceasing operations so that battery does not get overcharged or damage the cells outside its safe operating range.
A BMS looks like a computer motherboard and sits on the battery pack (inside the various cells) or close to it. Providing the correct information acts as a bridge between the inside of the battery, which drives the EV, and the external world.
The BMS manages a rechargeable battery to ensure that it operates safely and reliably. It is designed to monitor the battery pack and its cells, collect data and eliminate risks. It runs several algorithms to determine the charge left, which translates into the driving range. This is a crucial output called a state of charge (SoC). It’s like a car fuel gauge or a smartphone’s battery indicator.
The BMS also takes care of the vehicle’s state of thermal management.
SoC is helpful in a vehicle with a battery-swap option. You don’t end up with an old battery even if it’s fully charged, as you might get just 70% or 80% of the capacity, depending on how old the battery is. Besides, if it’s not charging 100%, but around 80%, it’s possible that a cell needs replacement –the continuous monitoring will help extend the overall battery life and performance of the EV.
EVs run on high-voltage lithium-ion (Li-ion) battery packs with risks of catching fire. These batteries must operate in pre-defined safe limits to ensure the safety of riders, passengers, and the EV. The BMS continuously monitors parameters like temperature, voltage, and the current in and out of the battery pack to keep it within safe limits. The BMS can adjust cooling and trigger auto cut-off to minimize fire risk or other damage. Overcharging can lead to thermal runaway and, potentially, an explosion. BMS monitors the supply of current to avoid overcharging. It can enforce limits of maximum charge or discharge.
The BMS determines how good an EV is. No wonder auto companies are increasingly being looked upon as tech companies. The geeks have their tasks cut out to ensure that an EV has the right BMS.
The longevity of the EV depends a lot on the BMS — how it does the juggling act of monitoring multiple parameters, taking decisions, sending alerts, improving the vehicle’s range, and ensuring the EV’s good health.
EV sales are likely to surge 84% in FY23 over the previous fiscal year, crossing 1 million units by the end of this fiscal year, according to the Society of Electric Vehicle Manufacturers (SMEV). Experts advise buying from companies investing in R&D and having their engineering units rather than importing and assembling EV kits.
If sales trends hold, by 2030, homes could have one or two EVs that require heavy-duty power sources to charge, and commercial buildings might have sizable EV fleets. Gupta says. This will not only transform your daily commute but may also help save the planet.