Most new electric vehicles are powered by lithium-ion (Li-ion) batteries which come with a long warranty, typically eight years/100,000 miles. Broadly speaking, warranties guarantee a battery capacity of at least 70 per cent of the original specification by the end of the warranty period.
Batteries in electric cars undergo ‘cycles’ of discharge (when you’re driving your car) and charge (when you plug your car in). Over time these cycles can reduce how much charge the battery can hold – and therefore, how far your EV can travel before needing to be recharged.
The good news is that electric car batteries don’t degrade as quickly as some predicted, so the lifespan of an EV battery could be 10, 20 years or more, especially if it’s treated well.
Fortunately, there are ways to reduce battery degradation, so fasten your seatbelts for our Top 10 tips:
1) Limit the number of charges. Your goal is to reduce the number of charging cycles that your battery goes through in its lifetime. Charging too often can cause chemical changes inside the battery itself, which again could negatively affect how efficiently it can store energy. If you have a home charger, this is the least damaging way to boost your EV’s battery. However, there’s no need to charge it every night if there’s plenty of charge left for the next day.
2) Avoid fully charging. Lithium-ion batteries are most efficient working in the charge range of 20-80%. Like anything else, taking something to its extremes will increase the rate at which it degrades. Going beyond those limits can increase the rate at which the battery deteriorates over time. Another reason to charge to 80% is speed at public chargers, which reduce the charge rate significantly after 80% to protect the vehicle’s battery.
3) Reduce exposure to extreme temperatures. Climate greatly impacts battery degradation because it affects the chemical reactions inside the battery. Freezing temperatures slow everything down, while blisteringly hot weather can create faster reactions. Both negatively affect your car’s battery and therefore the range you can travel. Parking your EV in a cool location, such as a ventilated garage or shady spot outside is advised during high temperatures.
In the depths of winter, temperatures can often drop considerably, slowing down charging speed and reducing range. Most people park their EV outside or in an unheated garage, resulting in the battery temperature matching that of its surroundings. As a result, a lot of energy is used to reheat the battery. If you have a garage, use a low-power heater to raise the temperature by a few degrees. If you park outside, use a cover. Try to charge the battery when it is still warm. Alternatively, preheat the battery before charging, if your car has that functionality.
5) Slow charge if you can. Public fast or rapid chargers (typically 50kW and above) increase the rate at which batteries degrade, so try to avoid them unless you have no option (i.e. on a long journey). It’s been estimated that eight years of standard charging will give you 10% more battery life compared to eight years of fast charging.
6) Drive smoothly. Sensible driving with less acceleration and deceleration will maximise the miles from each charge. It’s also beneficial to the long-term health of your electric vehicle’s battery.
7) Stay cool. It’s sensible to avoid charging your electric vehicle’s battery straight after a long or fast drive because the battery will still be hot. Leave it for a few minutes if possible, so the battery won’t have to work so hard. Charging a cool battery is better for overall battery health. That said, most modern EVs have temperature control systems which heat or cool the battery, so it should be fine, but always best to check your car’s manual.
8) Periods of inactivity. If you have to leave your EV parked for an extended period, it’s recommended that you charge it first (somewhere between 30% and 60% is recommended, but best to check the manufacturer’s guidelines). Some EVs also have special power save modes which are designed to minimalise energy consumption during long-term inactivity.
8) Flat EV battery. There really is no excuse for completely draining your battery – also known as a full or deep discharge. If you’re driving you will have been given multiple warnings that your car is running low. If you ignore these alerts, your EV will slow down and, ultimately, come to a complete stop. Most manufacturers protect batteries from becoming completely discharged, which can permanently damage the battery cells, by building in a small buffer zone – but it really isn’t worth the risk.
9) Battery health check. Most EVs feature software or are compatible with apps and devices that enable you to monitor vehicle and battery health. These tools can provide insights into battery voltage, temperature and cell balancing. By frequently checking your battery, you will have a higher chance of spotting any issues or drops in performance. Some EV specialist garages also offer an EV health check service.
10) Read the manual. Finally – and it may sound obvious – always read the owner’s manual for your electric vehicle. That way you learn about optimal charging for your car and find out other tips for keeping your battery (and vehicle) in tip-top condition.