An electric car works in a simple chain. A battery pack stores energy, an inverter turns it into the form the motor needs, and the motor turns the wheels. When you slow down, the motor runs backwards as a generator and sends a little energy back to the battery. It matters to you as a buyer because five spec-sheet numbers decide your real range, charging time and running cost. Read them wrong, and a bigger battery can cost you more without taking you any farther.

How does an electric car work, step by step?

Energy moves from the plug to the wheels, and back again when you brake. Follow it once, and the spec sheet stops looking like code.

From plug to wheels in seven steps

1. You plug in. At home, AC power from the grid reaches the car’s onboard charger, which converts it to DC. At a DC fast charger, that conversion happens inside the charger, so DC goes straight toward the battery.
2. The battery management system (BMS) controls how fast energy flows into the pack and keeps every cell within safe limits.
3. You press the accelerator, and the car’s controller asks the inverter for power.
4. The inverter turns the battery’s DC into AC and sets its strength and frequency, which controls the motor’s torque and speed.
5. The motor spins, and a reduction gear passes the motion to the wheels.
6. When you lift off or brake, the motor acts as a generator, and the inverter sends energy back to the battery.
7. All the while, a DC-DC converter steps the high voltage down to 12V for lights, screens and locks, and a thermal system keeps the battery and electronics at a safe temperature.

The main parts, and why each one matters to you

How does the battery work?

The battery is the costliest part of the car, so it’s the one worth understanding first.

What’s inside the battery pack?

Hundreds or thousands of small cells, grouped into modules inside a sealed, cooled case. Each cell stores a little energy. Together they give the pack’s capacity, measured in kilowatt-hours (kWh).

Here’s the catch. The brochure may quote the gross capacity, but the car lets you use only part of it to protect the cells. That part is the usable capacity, and it’s the number that decides your range.

kWh, kW and kWh per 100 km: which number tells you what?

Don’t mix them up, because one confusion costs real money. Range is roughly usable kWh divided by energy use per km. A 38 kWh battery in a car that uses 14 kWh per 100 km (0.14 kWh per km) gives about 270 km.

Which battery chemistry does your car use?

Two types are common: NMC (nickel-based) and LFP (lithium iron phosphate). LFP packs usually cost less and often tolerate full daily charges well. NMC packs hold more energy for their weight, and owners are often advised to keep daily charging nearer 80% to 90%. The right habit depends on the chemistry, so ask the dealer which one your car has, and follow the maker’s advice.

What does the battery management system do?

It’s the battery’s brain. It balances the cells, limits power in extreme temperatures, tracks the pack’s health, and keeps a hidden buffer at the top and bottom of the range. That buffer is why 0% on the dash isn’t truly empty, and why you shouldn’t treat the bottom of the gauge as a target. It also records the data a service centre reads when a warranty claim comes up.

How do the motor and drive work?

Why does an EV have no gearbox?

Electric motors make strong torque from a standstill and work efficiently across a wide speed range. So most EVs use one fixed reduction gear instead of a multi-speed gearbox. A few performance models use two speeds.

For you, that means smooth acceleration with no shifts, no clutch to service, and a simple drive selector. And it explains why a small EV can feel quick off the line.

What is regenerative braking?

When you lift off the accelerator, the motor resists the wheels and generates electricity. Many cars let you pick the regen strength, and some allow one-pedal driving.

• It helps most in stop-start traffic and on downhill stretches.
• It adds only a modest amount of range on a steady highway.
• It eases off when the battery is full or very cold.

Try each level on your test drive. Comfort with it varies a lot from person to person.

How does charging work?

AC charging: what the onboard charger does

On AC, the car’s onboard charger does the conversion, and its kW rating caps your home charging speed. A 7.2 kW wall box feeding a car with a 3.3 kW onboard charger still charges at 3.3 kW. So check the car’s rating, not just the wall box’s.

The socket and wiring set limits too. A standard 15A socket is the slowest option, and the wiring behind it has to carry a steady load for hours, which is a harder job than running a kettle for two minutes. Read whether any household socket suits any EV before you plug into one.

DC fast charging: why it’s faster

At a DC fast charger, the heavy conversion hardware sits in the charger, so power goes straight toward the battery through the CCS2 port. The car’s own limit still applies. A 150 kW charger can’t push 150 kW into a car that accepts 60 kW.

Charging is fastest in the middle of the battery and slows after about 80%, so trip plans use 10% to 80%. Heat is the enemy here, which is why the thermal system matters. Occasional fast charging on trips is normal, while constant high-power sessions add wear over the years. Whether fast charging always damages an EV battery looks at what the evidence says.

How long will charging take?

Divide the energy you need by the charger’s kW, then add about 10% for losses.

Real times vary with temperature, battery level and the charger itself.

How does an EV stay cool and warm?

The battery works best in a narrow temperature band, so most EVs use a liquid cooling loop. Some also use a heat pump to warm the cabin more efficiently.

• The cabin air conditioner and heater draw power from the main battery, so using them costs range.
• Hot weather and repeated fast charging both stress the pack.
• Ask the dealer whether the car has liquid battery cooling and a heat pump. Both help in India’s heat, and the first matters most if you fast charge often.

What is the 12V battery for?

It powers the lights, screen and locks, and it wakes the high-voltage system. The DC-DC converter normally keeps it topped up. But it ages like any 12V battery, and if it fails, the car may not start even with a full main battery.

The traction battery is a separate, high-voltage system, not a starter battery. That’s why a flat EV traction battery can’t be jump-started like a petrol car’s. It needs a tow or a mobile charging service. Some cars allow jump-starting the 12V battery, and your manual says how.

How is range worked out?

The brochure range comes from a lab test cycle. Real roads add air conditioning, speed, load, tyre pressure, hills and heat. Whether an EV’s advertised range is what every owner will achieve is the myth to check before you trust a brochure.

Use this instead: real-world range is about usable kWh divided by real-world energy use per km. Two cars with very different battery sizes can end up with nearly the same range, as the case study below shows.

Why does it matter for an EV buyer to know this?

Because every confusing line on a spec sheet maps to a buying decision. Know the map, and you can’t be sold the wrong car.

Questions to ask the dealer:

• What is the usable battery capacity?
• What is the onboard charger’s rating?
• What is the peak DC rate, and how long does 10% to 80% take?
• What did the car use per 100 km on this test drive?
• What does the warranty say about minimum capacity?
• Does the car have liquid cooling and a heat pump?

These questions sit inside the complete EV buying guide for India, which adds charging access, cost, insurance and resale.

What care is different in an EV?

An EV has no engine oil, spark plugs or clutch. But it isn’t maintenance-free.

• Coolant for the battery and power electronics, per the service schedule
• Brake fluid and a periodic brake check
• The cabin air filter
• Tyres, which carry a heavy car with strong torque
• The 12V battery
• Software updates
• High-voltage work, which belongs at an authorised workshop. Never touch the orange cables.

Case study: Vikram’s spec sheet

Vikram is a hypothetical buyer, not a real customer. He drives 60 km a day, charges at home overnight, and takes a 300 km trip once a month. He assumed the bigger battery was the better buy. Then he lined up the five numbers.

Car B’s battery is about 24% bigger, yet its range is almost the same. It’s heavier and less efficient, so it uses more energy per km. It also charges slower at home and on the road, and costs ₹2 lakh more.

So Vikram picked Car A. He confirmed the usable capacity, onboard charger rating and 10% to 80% time in writing, and he checked the energy use on a test drive. His monthly trip now needs one short stop. The lesson is that no single number decides anything. The five together do. These figures are illustrative.

A quick checklist

1. Ask for usable battery capacity, not gross.
2. Ask for real-world energy use per 100 km.
3. Divide one by the other to estimate range.
4. Check the onboard charger rating against your home charging plan.
5. Check the peak DC rate and the 10% to 80% time.
6. Ask which battery chemistry the car uses.
7. Ask about cooling, heat pump and warranty terms.
8. Test-drive your own commute with the AC on.

Five questions buyers ask after the basics

Why does my EV charge slower after 80%?

The BMS slows the current to protect the cells as they fill, much as you slow down when a glass is nearly full. The last 20% can take about as long as the whole stretch from 10% to 80%. Heat or cold slows it further. So plan trip stops from 10% to 80%, and leave when you have enough to reach the next charger with a buffer.

Does regenerative braking mean I can skip brake servicing?

No. Regen means the brake pads wear much more slowly, but the discs can rust from lack of use, and brake fluid still ages. Regen also drops when the battery is full or cold, so the friction brakes still do real work. Use them firmly now and then, and keep to the service schedule.

A red warning light appeared on my EV’s dash. Can I keep driving?

Treat a red warning as a stop signal until a workshop says otherwise. Amber usually means get it checked soon, and red usually means stop safely and call roadside assistance. Battery, high-voltage and brake warnings are the serious ones. Check your manual for what each symbol means in your model. And don’t open the bonnet cables or try to fix anything high-voltage yourself.

Why does my range drop so much with the AC on in traffic?

In slow traffic, the AC’s share of energy use per kilometre rises, because the car covers so little distance for the energy it burns. Hot weather also makes the battery use energy to cool itself. Pre-cool the cabin while the car is still plugged in, so the grid pays for it. Park in shade, set a moderate temperature, use recirculation and keep the tyres at the right pressure.

Can a software update change how my EV charges or drives?

Yes. Updates can adjust charging behaviour, regen, battery management and how the range estimate is calculated. Read the release notes, install updates while the car is plugged in with a healthy charge, and don’t panic if the range estimate shifts afterwards. Ask the dealer about the update policy and whether updates cost anything.