How does a battery management system work in a car?
Wednesday 23rd April 2025
Are you looking to buy your first hybrid or electric vehicle but are unsure how the battery functions? Or perhaps you’re worried about the future maintenance of these types of cars? Discover what a hybrid car’s battery management system does and how you can improve your battery life.
What is a battery management system?
A battery management system (BMS) is a computerised system in an electronic circuit which monitors, regulates and protects the charging and discharging of batteries. It observes the voltages, temperature, state of charge, power consumption and charging cycles of the battery pack to ensure the energy inside the battery is used optimally.
How does a BMS work in a car?
A battery management system in a car monitors battery performance and balances the state of charge, temperature, and communication between components in your car so it functions optimally while you’re driving. The BMS is typically hidden near the battery on the car floor and works quietly while you’re focusing on driving, delivering you real-time information for a smoother experience.
While hybrid cars utilise both a petrol or diesel engine alongside an electric battery, some vehicles are powered entirely by batteries. The BMS monitors the battery’s condition to power your car and calculates how long your car can travel before running out of fuel or energy.
Formula One Autocentres carry out additional checks in a hybrid service to check high voltage ports and cables, carry out hybrid diagnostics, and check high voltage coolant.
Most hybrid vehicle batteries are made from lithium-ion and function the same way as batteries in your mobile phones, laptops and other household appliances. This type of battery is preferred in electric cars as they provide high energy efficiency, have low self-discharge, and maintain performance in high-temperature scenarios. In other words, lithium-ion batteries are a lightweight, rechargeable and environmentally friendly option.
However, as no solution is perfect, there are some operational constraints:
- voltage requirements
- temperature restrictions
- current draw
- charging current
The BMS balances the above variables, such as adjusting to the temperature and voltage, to keep your car running steadily while you’re driving. An optimal BMS calculates how much charge is left and the overall condition of your battery which allows it to maintain the right charge level and prevent potentially dangerous situations. Which is why it’s essential you get your car checked regularly by a professional at your nearest Formula One Autocentres branch so they can spot any signs of damage.
Tips to improve your hybrid battery life
Prioritising battery health is crucial if you want a safe and reliable drive. Although an EV battery can last 8-20 years, gradual wear is inevitable after years of charging cycles, so maximising its lifespan is critical. Especially as it can cost as much as £15,000 to replace an entire hybrid battery!
- maintain a healthy charge range: Unlike smartphones, hybrid batteries benefit from a charge range between 20-80%. Avoid letting your battery drain completely as you’ll be more likely to break down and you can’t jumpstart an EV like a petrol or diesel car
- avoid overcharging: reduce frequent charging cycles and instead aim for steady depletion before recharging. Charging your battery too often can impact its long-term energy storage
- protect from extreme temperatures: extreme heat and cold force your BMS to work harder which can accelerate battery drain. You should park your car in the shade on hot days, or in an enclosed space in the winter to prevent it from freezing
- balance rapid charging with home charging: While convenient, frequent rapid DC charging stresses your battery if used too often. Try to charge your battery at home when necessary, as gentler home charging can preserve battery health
- avoid rapid acceleration and excessive speed: hybrid cars are known for smoother acceleration, so only apply gentle pressure to the accelerator. Consistent, steadier driving will help get the most out of your battery life
- allow your battery to cool before recharging: after a long drive, allow your battery to cool down before recharging. This ensures a more efficient and effective charge as the BMS doesn’t have to work as hard to regulate the temperature.
Hybrid vehicle services at Formula One Autocentres
Book an interim or full service to check your diesel, petrol or hybrid car’s health at your local Formula One Autocentres, where our expert technicians ensure your vehicle is safe, performs reliably, and serviced correctly to specifications.
