Electric cars: A comprehensive guide to understanding all the basics
EVs are most efficient between 50-80 km/h. If you’re doing highway runs, don’t expect anything more than 7 km/kWh at triple-digit speeds.
BHPian carmayogi recently shared this with other enthusiasts.
It’s mid-2022 and EVs are all the buzz. Globally, vehicles with this type of powertrain are selling like hotcakes. Finding an EV without a waiting list stretching months is unlikely.
Before we get into the nitty-gritty, note that an EV is actually a BEV, a Battery Electric Vehicle. Be cautious of anyone who includes a Plug-in hybrid as an EV. These vehicles are neither here nor there and all major European countries have stopped supporting their sales with incentives.
EV? kWh? kW? Watt? What???
Learning about the EV world means learning new terms, but these aren’t as confusing as they seem.
EV – Battery electric vehicle, featuring a large lithium-ion (usually) battery, one or more motors and inverters.
kWh – A kilowatt hour is a unit of electricity. Think of it as litres, kilograms or gallons in the fossil fuel world. A Tesla Model 3 or Y share the same battery options between 55 kWh and 79 kWh useable. Note the word useable – it’s because batteries always have a buffer to protect them. The 79 kWh pack mentioned here has 82 kWh gross capacity. Some manufacturers put larger or smaller buffers depending on their engineering decisions.
kW – A kilowatt is a unit of power. This is similar to bhp and has already been used in the EU for decades. A 150 bhp car is also a 110 kW car. Note that almost all EVs have ridiculous power figures and are fast. Electric motors allow this flexibility. All the world’s high-speed trains are electric, after all. Does this mean that one day, our beloved team-bhp might have to become team-kW?
SOC – State of charge. Your battery charge in percentage.
ICE – Good old Internal Combustion Engine. With climate change, it seems to be that ICE is melting the ice.
Range & Efficiency
As EVs become a mature tech, we’re seeing improvements in range & charging speeds. In a variety of operating conditions, an efficient EV would do between 7-10 km per kWh. Efficient EVs include all Tesla models and, for the Indian context, the Tata Nexon. Generally, EVs that are converted from ICE platforms are not that efficient, so it’s a good job by Tata to achieve this. By the calculation of 7-10km, a Model 3 Long Range should do 500-700 km on a charge. There’s a BIG caveat here. EVs are most efficient between 50-80 km/h. If you’re doing highway runs, don’t expect anything more than 7 km/kWh at triple-digit speeds.
How much range do you need?
Probably, not as much as you think. Humans tend to need bathroom breaks & food when travelling long distances by road. In my two round trips from Mumbai to Bengaluru, nearly exactly 1000km, I always stopped thrice, each way. By this simple example, I really only needed 333 km per charge but assuming a safety margin probably a car with >450 km range would be sufficient. This is a far cry from the demands of people unwilling to change who say they want 700km or 1000km because their ICE car can do it. The reality is, that not many of us can physically go so far. Here in the US, pretty much all the major highway routes have chargers located in food/rest stops. The idea is – drive, eat/toilet (while charging), drive, toilet (while charging) – rinse & repeat.
Another important consideration is the use case of the car. If this is your home’s second car or if you do not ever take road trips, then practically any EV is enough for you. When we discuss charging below, it’ll become clear why. A car roaming around Delhi or Chennai is unlikely to ever use more than ~100km on a single run.
There are two types of charging – Home or slow AC charging or Fast DC charging. AC charging means on a domestic plug essentially. This is perfect for overnight charging. DC fast charging is a bit more complicated because ‘fast’ chargers could have a peak output of anywhere between 50 kW & 350 kW. More on this in a bit.
For home/overnight charging, if you use a 3-pin plug-in India with an 8 amp limit, you can expect approx 1.8 kW of charging power. Depending on the efficiency of your EV, that’s about 9-18 km of range per hour because 1.8 kW charged for an hour results in 1.8 kWh in the battery, very simple to understand. If you use a higher capacity ‘fat’ 3-pin plug as we see on bigger air conditioners, you could do about 3.6 kW which would double the speed and half your charging time. For daily city use, let’s say 100 km, you only need 11 hours of charging in a relatively inefficient EV. 11 hours sounds like a lot, but if you come home at 7 pm and leave at 9 am the next day, that’s 14 hours! Cars are parked a lot over their lifetimes. The key is to have access to a plug where it’s parked. This is something for apartment buildings, office parking lots, public lots, malls etc to consider. AC charging is also gentle on the battery and helps maintain a long life for the cells.
For DC fast charging, every car has a charging curve. Batteries charge the fastest at low SOC. This is the same as any rechargeable battery device. Our cell phones all charge pretty quickly from 10% to 80% and slowly thereafter. A Tesla Model 3 will charge at up to 250 kW (!!!) but just for a couple of minutes when the battery is below 30%. The key thing here is time to 80% or 90% so you can continue your trip. For proper, fast charging EVs like the Teslas, Hyundai’s Ioniq 5, Kia EV 6, and Porsches & Mercs, this means 25-40 minutes. For those on long road trips, planning a stop to coincide with a food break means, in reality, not really waiting for the car to be ready. On several forums here in the US, you will find owners ‘complaining’ that the car is ready before they’re ready to continue. DC charging all the time will degrade the battery a bit more. However, worry not, there are several examples of EVs with >300,000 km on their battery packs that still have 80-90% of their original range intact. You’d struggle to find a 300k km ICE car that does not need a major engine job.
For charging networks, there is one clear leader, Tesla. Tesla has over 35,000 supercharger stations globally. If you navigate using Google maps built-in to the car, it will tell you where you need to stop for a charge, how much you need to charge and how many spots are available in real-time. All charging is plug & charge, so you stick the plug in and go away. The car will bill your credit card at the end of the session. This is the gold standard which will slowly be copied. For other brands, you need to rely on third-party websites to pre-calculate your trip and some guesswork on your consumption & range.
Other networks of note are Electrify America here in the US & Ionity in Europe.
Also note that most battery chemistries are best used between 10% & 80% SOC, particularly NMC & NCA chemistries. These batteries don’t like being charged to 100% or drained to 0%. You can still do that, but do it while the car is in use. Do not park with a dead or full battery for several hours or days. This will lead to quicker battery degradation. Iron-based battery chemistries, commonly known as LFP batteries are less sensitive, but these batteries tend to be heavier and work for lower-midrange cars or stationary energy storage.
The reason EVs are being championed so hard is their energy efficiency. Between the power plant, transmission, charging & use of energy, the round trip efficiency is between 75-90%. In the US, we have a rating known as the miles-per-gallon equivalent. Think of it as km/l equivalent. The most efficient EVs here are rated at 130-140 Mpge compared to 50 for the best ICE car. The actual quantity of energy being carried around in a long-range EV is approx 9-12 litres of fuel. 9-12 litres can take you 500-700 km. Mind-blowing! This is also the reason why an EV running off coal or natural gas power is still significantly cleaner than a fossil car. Furthermore, if the grid gets cleaner over the life of the car, the car automatically gets cleaner, something impossible in an ICE platform. Where possible, EVs can be coupled with solar, say if your office parking lot has a solar canopy. In this case, you can drive off the sun. Science fiction much?
Is an EV good for you?
In most cases, yes. Unless you’re a hard-core road tripper, an EV will do just fine. These cars are more fun to drive with their zippy instant response, satisfying in stop-go traffic with regen braking & silent ‘idling’ and, most importantly, are virtually maintenance-free. There are threads, even here on team-bhp, of owners who, after 3 yrs and 50k km had to change the air conditioner filter and wiper blades only, apart from tyre rotation & maintenance. In the long run, EVs will be a dagger to the heart of the dealer network. There’s simply not much they can charge us for. Dealers will have to end up being body shops with small diagnostic teams for any mechanical issues.
EVs are very expensive, still. However, a close analysis of Tesla’s financials shows that they have gone from a loss-making company to making over 30% gross margin on their cars. Toyota makes just 18% in comparison. Tesla is using a lack of supply to keep prices high. This bodes well for the future when we will see price reductions from production efficiency, scale & supply chain improvements. We’re already seeing a slew of Chinese makes selling long-range EVs at less than $30,000 – some even less than $20,000 in their domestic markets. For India, a price range between Rs 10 lakh to Rs 25 lakh would be the sweet spot. Currently, the American, European & Korean brands all start above that. Time will be our friend with EV pricing but is there time available for us to clean up our cities?
Our favourite brands
This is a bit of prediction time but be prepared for some famous automotive names to either be in trouble or go bankrupt altogether. The EV revolution is similar to, although slower than, the mobile phone revolution. Today, there isn’t a Panasonic phone (remember their ubiquitous cordless phones?) or a Nokia to buy. The same will happen with a bunch of slower-moving car companies. For now, the signs look good for VW group, Hyundai-Kia & Ford among those that we know well. The Japanese brands are all behind the curve. Expect some pain, some bloodshed and a lot of consolidation in the next 5 years.
Some qualifying points
Here’s what BHPian soarersc300 had to say on the matter:
Excellent comprehensive post
Just wanted to add a bit to the part about battery chemistry. LFPs are now found in half of Teslas manufactured last quarter and will over a period of time replace other Li ion chemestry options.
The thing is with LFP the usable range is the same as an actual range. Whereas in other types the usable range is about 60% of the actual range (20 to 80). Usability here is both in terms of the practicality of time needed during charging pit stops (you charge till 80 and drive off, which makes more sense time-wise) and also in terms of battery degradation.
So a 300 km range LFP BEV is almost the same as 500 km range BEV using NMC or NCA.
Some of the other advantages of LFP are:
- Longer life (almost 10x charging cycles)
- Stable at higher temperatures (helps in India)
- Less prone to catch fire in event of an accident
- Environment-friendly to manufacture
- Raw materials are more readily available
Here’s what BHPian ajayc123 had to say on the matter:
That’s very insightful. Power generation using turbines, etc is happening at near best efficiency at most times, whereas ICE energy efficiency varies a lot during the ICE operation due to varying rpm’s ( especially the conventional otto cycle-based ICEs), and hybrid ICE efficiency (Atkinson based) would be somewhere in between. So makes perfect sense for the green warriors. I am sold.
And yes solar is off the sun, which is an infinite source of energy for the foreseeable future.
If I think of it, the last century was an oil economy, whereas the current century could turn out to be a solar economy. Regions blessed with abundant sunshine could be generating surplus power and gradually reduce the dependence on polluting fossil fuels. Countries with oil and gas reserves could take a backseat. It may sound like fiction, but the next wave of colonization (not the British way, but the corporate way) could revolve around solar. Hint: Africa.
Yes, we could breathe fresher air.
Here’s what BHPian enj0y_ride had to say on the matter:
Thank you. Very nice write-up. One point which will slow the adoption is that most urban populations who live in apartments do not have access to charging infrastructure ( I mean the slow overnight chargers ).
Even in the organisation where I work, they stopped providing charging facilities in the parking area. The reason is they are not able to give free access as the EV count increases. Since it’s an SEZ, they can’t charge employees either.
Here’s what BHPian Lokesh Soni had to say on the matter:
Nice writeup !!
Interesting fact: A bit more than 100 years back (~ the 1910s), EVs were sold more than ICE vehicles. But then the provision/convenience of refuelling the fuel in seconds led to ICE overtaking EVs (main reason). Battery technology was too poor back then, so we had put our full bandwidth into exploring ICE technologies. Motor technology has not changed significantly in 100 years, they were as good as they are now.
Now after 100 years batteries’ R&D is mature, still, it is the battery which is the major focal point in EV R&D.
Check out BHPian comments for more insights and information.
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