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As the number of electric vehicles (EVs) on our roads increases, they are becoming more accepted by drivers who seem to have stopped pointing out “one of those electric cars” to anyone who is in earshot. Most car manufacturers now offer a range of EVs with prices which are becoming more affordable and therefore becoming more appealing and acceptable to a wider market.

With these increasing numbers, the discussion is now beginning to turn more towards running costs and cost of ownership. The all-important life cycle cost is becoming a more discussed element of EV ownership. It is crucial to look at the cost of ownership as well as the purchase cost of any piece of equipment you buy. Electric vehicles go through tires 30% faster than fossil fuel powered vehicles for instance, and one of the items now coming under regular scrutiny is the large, heavy battery of an EV which is responsible for the excessive tyre wear. How long will your battery last and how much would it cost to replace it?

Currently, the main battery technology being used in EV batteries is lithium-ion. They have high energy density and can be recharged frequently. The same technology is used in batteries for electric scooter and bikes as well as mobile phones. EV batteries however, are much larger and contain substantial quantities of the materials required to manufacture them, which is understandable when you consider that they may well be asked to propel a vehicle weighing around 1.6 tons at speeds up to 70 mph for distances in excess of 200 miles at any given time.

That being the case it should come as no surprise that they are expensive. The bigger the battery the higher the cost, with a general rule of thumb stating a current figure of around £120 per kWh of battery, meaning a 75 kWh battery could cost around £9,000 to replace.

Replacing an EV battery is not something that most drivers should ever need to do, never mind pay for. An electric vehicle battery will normally last somewhere between 10 and 20 years, with most manufacturers offering at least a five year warranty on their battery. Many manufacturers, including Nissan and Toyota, offer an eight-year or 100,000 miles warranty on their EV batteries. This normally covers the battery degrading to a certain degree, often around 70% of original performance, rather than a catastrophic failure. One major manufacturer has stated that their batteries would outlast their cars twice over. If your manufacturer’s warranty doesn’t cover the cost of a replacement battery, your car insurance may well do so.

It also should be stated that a faulty EV battery might not need to be replaced but may possibly have underperforming cells identified and replaced. This would most certainly be a more cost effective option worth considering if battery life and range become a problem in an older vehicle.

There are other considerations which will affect the life of an EV’s battery. As with most items in regular use, the care taken in how the item is used will help to improve the health of the battery and ultimately extend its life.

It is never recommended that you drive a petrol or diesel car until the fuel tank is almost empty. Similarly with an EV you should not allow the battery to get close to zero percent charge, however, unlike a fossil fuelled car, recharging to fully charged is not recommended as both zero charge and fully charged will adversely affect the life of the battery. Most manufacturers recommend keeping an EV battery charged to between 20% and 80% whenever possible. As most EVs tend to be charged at home overnight when the driver is asleep, it is not practicable to monitor the charge and stop it when it reaches 80%. Thankfully, most EVs have a control in the settings menu that allow you to choose how much charge you put in. Simply set the charge amount to 80% and the car can be plugged in for its overnight charge safe in the knowledge that it will stop charging when it reaches that set level.

If the car is to be used for a longer than normal journey the next day, the charge amount can be altered, allowing the battery to be fully charged for that day. Fully charging an EV battery occasionally will not harm it to any great degree, although keeping it fully charged is not recommended by the manufacturer.

Longer journeys may mean using rapid chargers to top up the battery en route. The repeated use of rapid chargers will affect the life of the battery, it is always better to charge a battery slowly. Rapid charging is also the most expensive method of charging an EV, which is another good reason for avoiding it.

Modern cars are loaded with electric and electronic safety features and driver convenience devices, all of which use a certain amount of charge from the battery, with some continuing to operate even when the car is parked and at rest. The loss of charge is not substantial and should not be a concern if for instance, the vehicle will be parked up while the owner goes on holiday, provided the period of inactivity would be no more than a month or so. It would be generally expected that an EV parked up for a period of time would lose around 1% of its charge per day. If you are liable to be away for a longer period, it might be worth leaving your EV plugged into a home charger with the maximum charge set to 50%. A smart charger would allow you to monitor the charge from your smartphone and make any adjustments necessary.

In general terms, it is not recommended that you leave an EV plugged into a charger unnecessarily, but plug it in when charging is required, as this is better for the health of the battery.

Quoting an EV battery life of 10 to 20 years may seem slightly ambiguous, perhaps even unhelpful, but your battery lifespan really does depend on how well it is looked after. Factors like heat, cold, or regular swift charging can negatively affect battery life and reduce performance. If you look after your EV’s battery, it may well outlast the vehicle and save you the not prohibitive cost of replacing it.