2018-2022 · Electric · 42.2 kWh battery (170 hp / 184 hp S)
BMW's quirky carbon fiber electric city car with significantly improved 120Ah battery offering realistic 240-260 km range. Popular among urban drivers for its tight turning circle and rear-wheel drive fun. The 120Ah battery shows minimal degradation compared to early 60Ah models, but watch for 12V battery failures, rapid tire wear on narrow 155/70R19 tires, and potential drivetrain issues after 100,000 km. Carbon fiber body means low running costs but specialized repair facilities required. Winter range drops 20-40% depending on heating use. Verify battery capacity test and all software updates completed.
Expected Annual Maintenance Costs
€650 - €1,100/year
15,000 km/year
Fixed costs
€450-700
Risk buffer
€200-400
What Can Break
bars = likelihood
12V auxiliary battery failure€150 - €350
Premature 12V battery failure is extremely common, often within 3 years · more· less
This is the single most common i3 issue worldwide. The 12V auxiliary battery (not the main high-voltage battery) fails prematurely, sometimes within 36 months. When it dies, the entire car becomes unusable and requires flatbed recovery. Symptoms include DC charging glitches, charge port failing to open in cold weather, and random dashboard warnings. Many owners proactively replace every 3 years at €150-200 DIY or €260-350 at BMW dealers. The AGM battery type is more expensive than standard batteries. Complete failure leaves you stranded.
Tire wear (155/70R19 narrow tires)€250 - €1,000
Rear tires wear extremely fast, often needing replacement every 15,000-25,000 km · more· less
The i3's narrow 155/70R19 tires are co-designed with Bridgestone for low rolling resistance, resulting in notoriously rapid wear. Rear tires wear almost twice as fast as fronts due to the rear-wheel drive and instant electric torque. Owners report rear tires becoming "almost like slicks" after just 15,000 km. Bridgestone Ecopia EP600 costs around €250 per tire, meaning a full set runs €1,000. Limited tire options available - mostly Bridgestone in North America, with Continental and Michelin options in Europe. The specialized size and design contribute to high replacement costs.
Battery degradation (capacity loss)€0 - €18,000
120Ah batteries show minimal degradation; average 2-4% annually, typically 10-15% at 80,000 km · more· less
The 120Ah battery (2018+) is significantly better than earlier 60Ah models. Multiple owners report minimal capacity loss even after 100,000+ km. Samsung SDI specs show the 94Ah cells can handle 4,600+ charge cycles before reaching 80% capacity. However, degradation accelerates in extreme climates - Phoenix heat can cause faster cell damage. BMW warranty covers catastrophic failure or degradation below 70% for 8 years/160,000 km, but gradual loss isn't covered. Replacement cost ranges €15,000-18,000 outside warranty. Fast charging more than 5-10 times monthly accelerates degradation. Early 60Ah models showed up to 30% loss in 3 years, but this is not typical for 120Ah batteries.
Electric motor / drivetrain failure€600 - €7,000
Motor bearing failures and EME (Electric Motor Electronics) faults occur, typically after 80,000-140,000 km · more· less
The eDrive motor and EME (Electric Motor Electronics) can fail, causing complete drivetrain shutdown. Motor bearing failures cause excessive rotor play, which damages the position sensor and can destroy the EME module. New EME from BMW costs €5,400 plus €1,700 labor (total ~€7,000). UK repair services offer EME rebuilds for approximately €3,200. Salvage motors from Norway available for €600-1,500. Some owners report grinding gearbox noises after 50,000 km. BMW has stated the design life is 150,000 km, though many exceed this. Complete motor replacement at dealer can exceed €10,000.
Onboard charger (KLE) failure€3,000 - €5,700
Early 2014 models had KLE failures; BMW reduced charging power via software, then replaced under warranty · more· less
The KLE (onboard charger) had design flaws in early 2014 models. BMW initially pushed a software update limiting charging to 4-5.5 kW (50% reduction) to prevent failures, then replaced affected units under warranty with improved versions. Dealer KLE replacement costs around €5,700. If one of the two internal chargers fails, maximum AC charging drops to 3.6 kW while DC fast charging remains unaffected. Most 2018+ 120Ah models have the updated KLE, but used 2018-2019 cars may still have older units if not replaced under service action B61 31 14.
Brake disc corrosion€300 - €800
Regenerative braking means discs corrode from lack of use; typically need replacing at 60,000-80,000 km · more· less
Because the i3 uses regenerative braking extensively, the friction brakes are rarely used, leading to rust and corrosion. By 80,000 km, many owners find rear discs completely corroded despite pads still being thick. BMW builds in periodic automatic brake application to offset this, but it's not always sufficient. Front discs and pads replacement quoted at BMW dealers: €390-500. Complete brake job (front and rear) can exceed €1,000 at dealers. Independent specialists charge significantly less (€450-650 total for both axles with quality parts). Brake sliders need re-greasing every 3-4 years.
Charging port door solenoid failure€200 - €450
Charge port door solenoid commonly fails, making grinding noise when opening/closing · more· less
The electric solenoid that opens and closes the charge port door is a known failure point. First symptom is grinding noise, eventually progressing to complete failure where the port won't open. This prevents charging unless manually opened. Replacement at BMW dealers costs €200-450 including labor. The part itself is relatively cheap, but labor adds cost. Some owners have reported the door failing to open in cold weather, which can be related to weak 12V battery rather than solenoid failure.
Driver seat heater failure€300 - €600
Poor seat wiring design causes premature wire wear, leading to heater failure · more· less
Driver seat heater failure is surprisingly common due to poor wiring design in the seat causing premature wear. This is particularly frustrating in an EV where seat heaters are preferred over cabin heating to conserve range. Repair requires seat removal and wiring harness replacement. BMW dealer repair costs €500-600. Independent repair may be possible for €300-400. This is important because using seat heaters instead of the cabin heater can extend winter range by 10-15%.
Reliable electric drivetrain, but watch consumables and 12V battery
The 120Ah i3 (2018+) has proven more reliable than early 60Ah models. The electric motor and battery pack are generally robust, with minimal degradation reported even at high mileage. Main concerns are consumable items (tires, brakes) and the notorious 12V battery. Budget for tire replacements every 20,000-30,000 km. Proper charging habits and avoiding excessive DC fast charging help preserve battery health.
Pre-Purchase Inspection Checklist
General checks
Service history
Complete BMW service records essential. Verify software updates completed.
Tires
Check tread depth (rear wears faster), age date codes, and unusual wear patterns. Budget for replacement soon if below 4mm.
VIN check
Use vehicle history service (CarFax/AutoCheck) to verify mileage, accidents, and service records.
Body condition
Carbon fiber body doesn't rust, but check plastic panels for cracks or damage. Verify repair facility is CFRP-certified if accident history exists.
12V battery
Ask when 12V battery was last replaced. If over 3 years old, budget for immediate replacement.
Specific for this vehicle
Battery capacity test
Request official BMW battery capacity test showing kWh or Ah remaining. 120Ah should show 38+ kWh at 100,000 km. Below 35 kWh (83%) indicates significant degradation.
Charge port operation
Test charge port door multiple times - listen for grinding noises. Door should open/close smoothly electrically and also manually.
Test charging at AC and DC
If possible, test both Level 2 AC charging (should reach 7.4 kW) and DC fast charging to verify KLE and charging system work properly.
Check for drivetrain error messages
During test drive, watch for any "drivetrain malfunction" warnings. Listen for grinding or unusual noises from motor/gearbox.
Verify KLE software update completed
For 2018-2019 models, ask dealer to confirm service action B61 31 14 (KLE update) was completed. Cars should charge at full 7.4 kW.
Cold start test
If buying in winter, test cold weather range. Expect 20-40% reduction depending on temperature and heating use.
Brake disc condition
Inspect all brake discs for heavy rust or corrosion. Light surface rust is normal, but deep corrosion indicates neglect.
Infotainment and electronics
Test all screens, ConnectedDrive features, and BMW apps. Check for software freezes or glitches during 20+ minute test drive.
Check for steering assist warnings
Some i3s have steering assist reduction issues. Verify no steering-related error messages appear.
Range test
Fully charge to 100% and note displayed range. 120Ah should show 240-260 km in normal conditions. Significantly less indicates battery degradation.
Power steering intermittent failure at startupTSB available
Verify all TSBs and updates completed
Contact BMW dealer with VIN to verify all Technical Service Bulletins and software updates have been completed. The KLE charging update is particularly important for 2018-2019 models. Multiple steering and charging-related TSBs exist - ensure these are addressed.
Warranty Status
Factory warranty (3 years)Expired on 2018-2020 models
High-voltage battery warranty8 years / 160,000 km (EU) / 100,000 miles (US)
Battery coverage thresholdBelow 70% original capacity
Certified Pre-Owned warranty transferBattery warranty transfers to new owner
Strong battery warranty, but gradual degradation not covered
BMW offers one of the best EV battery warranties at 8 years/160,000 km in Europe (8 years/100,000 miles in US), covering defects and extreme degradation below 70% capacity. However, gradual degradation (e.g., 85% to 75% capacity) is not covered. BMW has extended this warranty from the original 100,000 km to 160,000 km in Europe. The warranty transfers to subsequent owners. Note: Not a single BMW i3 high-voltage battery has reportedly been replaced due to premature aging under normal use.
This report is for informational purposes only and does not constitute professional advice. Estimates may be inaccurate. Always have a qualified specialist inspect the vehicle before purchase. We accept no liability for decisions made based on this information.