The BMW i8 is a plug-in hybrid, not fully electric

The BMW i8 runs on both a petrol engine and an electric motor, which makes it a plug-in hybrid electric vehicle (PHEV), not a pure electric car. It has a 1.5-litre three-cylinder turbocharged petrol engine paired with an electric motor powered by a rechargeable battery. When the battery runs out, the petrol engine takes over — so you cannot drive it on electricity alone for an entire journey the way you can with a fully electric vehicle.

This matters because it changes how you use the car and what you pay to run it. If you drive short distances most days, you might use almost no petrol. If you take longer trips regularly, you will rely on the petrol engine often. The car decides automatically which power source to use based on speed, battery charge, and driving conditions.

Key Takeaways

  • The BMW i8 has both a petrol engine and an electric motor, so it is a plug-in hybrid, not fully electric.
  • The battery gives you roughly 20 to 30 miles of electric-only driving before the petrol engine starts, depending on the model year and driving style.
  • You must plug it in to recharge the battery, but the petrol engine also charges it while you drive.
  • Plug-in hybrids cost less upfront than fully electric cars but more than conventional petrol cars, and fuel costs fall somewhere in between.

How the BMW i8's hybrid system actually works

The i8 uses what BMW calls eDrive technology. At low speeds — typically under 50 mph — the car can run on electric power alone if the battery has charge. The electric motor produces around 143 horsepower on its own. When you accelerate harder, need more power, or the battery runs low, the petrol engine kicks in to help or take over entirely.

The petrol engine does double duty: it powers the wheels and it also runs a generator that recharges the battery while you drive. This means you do not have to plug in every time the battery empties, though plugging in is more efficient than letting the engine charge it. The system can also recover energy when you brake — called regenerative braking — which puts some charge back into the battery without using the engine.

The battery itself is relatively small compared to a fully electric car. Depending on the model year, it holds between 7 and 11.6 kilowatt-hours of energy. That is enough for short commutes or city driving on electricity, but not for long motorway trips.

Electric-only range and real-world driving

BMW rates the i8's electric range at around 20 to 30 miles, though the exact figure depends on which generation you are looking at and how you drive. Newer models (2018 and later) have larger batteries and can reach closer to 30 miles. Older models fall short of 20 miles in many cases.

Real-world range is usually lower than the official figure. Motorway speeds, cold weather, and aggressive acceleration all reduce how far you can go on electricity. If you drive mostly on city streets at moderate speeds, you might see the upper end of the range. If you spend time on faster roads, expect less.

The key question is whether your typical daily driving fits within that range. If you commute 15 miles each way and charge overnight, you could do most of your driving on electricity. If you regularly drive 50 miles or more in a day, the petrol engine will run for a significant portion of your journeys.

Charging the BMW i8 at home and on the road

You can charge the i8 using a standard three-pin household socket, though this is slow — it takes roughly 8 to 12 hours for a full charge depending on the model. A dedicated home charging point (a wallbox) cuts that to 3 to 4 hours. Most owners install a wallbox because the time saving is worth the cost, especially if you charge overnight.

Public charging networks work too, but the i8 charges more slowly than fully electric cars because its battery is smaller. A 30-minute rapid charge at a public point will add maybe 15 to 20 miles of range, not the 100+ miles you might get from charging a Tesla or Volkswagen ID.4.

Because the petrol engine can charge the battery while you drive, you are not stranded if you forget to plug in. You lose the efficiency benefit of electric driving, but the car still works. This is a real advantage over fully electric vehicles if you do not have reliable access to charging.

Fuel and electricity costs compared to other cars

Running costs sit between a petrol car and a fully electric car. If you charge regularly and drive mostly short distances, your fuel bill drops significantly because you use less petrol. If you drive long distances or rarely charge, you will spend more on fuel than you would in a conventional petrol car because the i8 is heavier and less efficient when the petrol engine is the only power source.

Electricity is cheaper per mile than petrol in most places, so every mile you drive on battery power saves money. The exact saving depends on your local electricity rates and petrol prices, both of which vary. A rough guide: if you drive 50 miles a day and 30 of those are on electricity, you use about 20 miles worth of petrol instead of 50, cutting your fuel bill by roughly 60 percent compared to driving the same distance in a conventional petrol car.

Maintenance costs are higher than a standard petrol car because you have both an engine and an electric system to service. The battery itself is covered by warranty (usually 8 years or 100,000 miles), but once that expires, replacement is expensive — often £5,000 to £10,000 or more depending on the model year and damage.

Why BMW made the i8 a hybrid instead of fully electric

When the i8 launched in 2014, battery technology was less advanced than it is now. A fully electric car with the i8's performance would have needed a much larger, heavier battery, which would have made the car slower and more expensive. The hybrid approach let BMW deliver sports-car acceleration and a reasonable driving range without the weight penalty of a large battery pack.

The i8 was also designed to appeal to drivers who wanted electric efficiency for daily driving but did not want to worry about charging infrastructure or range anxiety on longer trips. The petrol engine was the safety net.

By today's standards, the i8's approach feels dated. Modern fully electric cars like the Porsche Taycan and Tesla Model S offer better performance and longer range than the i8, and they do not need a petrol engine at all. BMW has since launched fully electric models like the i4 and iX, which represent where the company is heading.

Should you buy a BMW i8 if you want an electric car

If you are looking for a car that runs on electricity most of the time and you have a place to charge at home, the i8 can work — but only for short commutes. If you need a car that can drive 200+ miles on a single charge without stopping, a fully electric vehicle is a better choice.

The i8 is also expensive to buy secondhand, and repair costs are high because it is a specialist car with a complex hybrid system. Insurance premiums are typically higher than for conventional cars of the same age. If your main goal is low running costs and environmental impact, a newer fully electric car or a conventional hybrid (not plug-in) might be better value.

The i8 makes sense if you want a distinctive sports car that happens to have electric capability, not if you are primarily shopping for an electric vehicle. It is a petrol car with an electric information, not an electric car with a petrol backup.

Frequently Asked Questions

Can the BMW i8 run on electricity alone?

Yes, but only for 20 to 30 miles depending on the model and how you drive. Once the battery is empty, the petrol engine starts automatically. You cannot drive it like a fully electric car for an entire day without the engine running unless your daily driving is very short.

How long does it take to charge a BMW i8?

A standard household socket takes 8 to 12 hours for a full charge. A dedicated home wallbox takes 3 to 4 hours. Public rapid chargers add 15 to 20 miles in 30 minutes, which is slower than fully electric cars because the battery is smaller.

Is the BMW i8 cheaper to run than a petrol car?

It depends on how much you drive on electricity. If you charge regularly and drive short distances, yes — you use far less petrol. If you rarely charge or drive long distances, the i8 costs more to run because it is heavier and less efficient when only the petrol engine is working.

Can I drive a BMW i8 without charging it?

Yes. The petrol engine will charge the battery while you drive, so you can use the car like a normal petrol car. You lose the efficiency and environmental benefit of electric driving, but the car still works. You are not stranded if you forget to plug in.

Is the BMW i8 being replaced by a fully electric model?

BMW stopped making the i8 in 2024. The company is moving toward fully electric sports cars instead. If you want a new BMW electric vehicle, the i4 and iX are the current options, both of which are fully electric with no petrol engine.