Batteries are often guaranteed to have around 70% of their original capacity after seven years. And this guarantee is usually transferable (with Nissan and BMW, this transfer only applies to a private sale). If you’re buying second-hand from a garage, get crystal clear reassurance on whether the battery is covered by any warranty. Ask to have the details in writing and scrutinise them closely. If you’re buying privately, check the car’s ownership history carefully and, if necessary, call the manufacturer for advice.
If the battery needs replacing, the good news is that it might not cost as much as you fear. A replacement new battery for a first-generation Leaf, for example, cost just £4,920 in 2014. More recently, re-fabricated packs have dropped the price to around half that.
Even if the battery’s still got life in it, you can restore or even upgrade the battery pack. And the cost of doing this is only likely to come down, with more, older electric cars on the road.