BMW i3 buying guide: batteries, range extender and what to check
The BMW i3 is a unique electric city car with a carbon fibre body. This buying guide covers battery sizes and range, the range extender, the i3s, common issues and what to check.
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The BMW i3 is one of the most innovative cars BMW has ever built. Produced from 2013 to 2022, it combined an electric drivetrain with a passenger cell made of carbon fibre reinforced plastic, an unusual design and a sustainable interior.
Today, it is an affordable used electric car that is perfect for city driving. But battery size, the optional range extender and the car's history make a big difference. In this buying guide we explain the BMW i3 versions, batteries, range, common issues and what to check before you buy.
A unique electric BMW
The i3 was designed from the start as an electric car. Its key features include:
- A carbon fibre reinforced plastic passenger cell, making the car light and strong.
- An aluminium chassis that holds the battery and drivetrain.
- A rear-mounted electric motor driving the rear wheels.
- Rear-hinged rear doors, which open in the opposite direction to the front doors.
- Sustainable materials in the interior, such as natural fibres and responsibly tanned leather.
It is compact, agile and quick off the line, making it ideal for city driving.
The i3 also has a very tight turning circle, which makes parking and U-turns easy. Its tall body gives good visibility and a surprisingly roomy feel inside for such a short car. Many owners say it is one of the most enjoyable city cars they have driven.
Battery sizes and range
The i3 was offered with three battery generations, often described by their cell capacity:
- Early battery: the smallest capacity and the shortest range.
- Mid-life battery: larger capacity and improved range, introduced around 2016.
- Final battery: the largest capacity, introduced around 2018, offering the longest range.
Real-world range depends on battery size, age, temperature, speed and driving style. Later cars are much more usable for longer trips. Check the battery size in the vehicle documents and ask for a battery health report if possible.
The range extender (REx)
Some i3 cars were offered with a range extender, known as REx. It is a small petrol engine that acts as a generator, charging the battery when it runs low. It does not drive the wheels directly.
The REx removes range anxiety on longer trips, but it adds weight and maintenance needs, such as oil changes and petrol system care. In some markets, the REx fuel tank size and operation were limited by regulations. Check that the REx starts and runs correctly, and ask for its service history.
BMW i3 and i3s
From around 2018, BMW offered the i3s, a sportier version with more power, sport suspension, wider tyres and a slightly different design. It is quicker and more agile, while the standard i3 is more comfortable and efficient.
Both versions are great city cars. Choose the i3s if you want more performance and a sportier feel.
Common issues
Points to check include:
- Battery health, which affects range. Ask for a diagnostic report.
- The 12-volt battery, which can cause warning messages or prevent the car from starting. Our article on BMW battery drain explains 12-volt battery problems.
- The range extender on REx cars, including starting and running quality.
- Charging function, both AC and DC fast charging where fitted.
- Narrow tyres, which can wear quickly and are sometimes hard to find in stock.
- Suspension parts on cars used on rough roads.
Most i3s are reliable, but a thorough inspection is still important.
Charging
The i3 charges from a household socket, wallbox or public AC charger. Many cars also support DC fast charging, which allows quick top-ups on longer trips.
Our article on how to charge an electric BMW explains home and public charging, charging speeds and battery care tips. A home wallbox is the most convenient solution for daily use.
Who the i3 suits
The BMW i3 suits drivers who:
- Drive mostly in towns and cities.
- Can charge at home or work.
- Want low running costs and a fun, compact car.
It is less suited to drivers who regularly cover long distances on motorways, especially with the early battery. Our article on BMW plug-in hybrids explains another option for mixed use.
Buying tips
When buying a used i3:
- Check the battery size and health.
- Test charging with the car's cable and, if possible, a fast charger.
- Check the REx, if fitted.
- Look at tyres, brakes and suspension.
- Read the fault memory.
- Ask about the remaining battery warranty, which may still apply in some markets.
Our complete checklist for buying a used BMW covers other checks. A well-chosen i3 is one of the most enjoyable and affordable ways into electric driving.
BMW i3 key facts
| Item | Details |
|---|---|
| Production | 2013 to 2022 |
| Body | Carbon fibre reinforced plastic passenger cell |
| Drive | Rear-mounted electric motor, rear-wheel drive |
| Batteries | Three generations with increasing range |
| Range extender | Optional small petrol generator (REx) |
| Sportier version | i3s from around 2018 |
| Best for | City driving with home charging |
Frequently asked questions
Is the BMW i3 reliable?
Generally yes. Battery health, the 12-volt battery and the range extender on REx cars are the main points to check.
What is the BMW i3 REx?
A version with a small petrol engine that acts as a generator to extend range when the battery runs low.
Which BMW i3 battery is best?
The final, largest battery offers the longest range and is the most practical for longer trips.
Is the BMW i3 good for motorway driving?
It can handle motorways, but it is best suited to city and suburban driving, especially with smaller batteries.
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