Question of the Week: Is it safe to buy a secondhand EV that's stood unused?

David Ross, Editor
Fri, 11 Oct 2024

Dear Honest John,

"I'm considering buying a lightly-used Mercedes-Benz EQB 350, which was first registered in June 2022. It's done 3000 miles and seems to have been sat at a dealership for much of its life. Does this represent a risk to the health and lifespan of the battery? If so, how would I assess this when test driving / inspecting?"

- W

Dear W,

An EV that has been stood unused will not experience any issues other than those that would affect any vehicle regardless of its engine, such as potential corrosion of the brake discs and tyres that have flattened off, neither of which should present any particular problem.

Lithium-ion batteries, as fitted to the vast majority of electric vehicles, lose around 1-3% of their charge a month, which is considerably less than the 5% expected loss from a 12V vehicle battery over the same period.

Think of the drive battery in an EV in the same way you would of a phone battery. Charging your phone overnight and then using it all day puts it through more strain and takes more life out of it than if you left it charged but unplugged.

As long as the vehicle has been stored with a reasonable amount of charge in the drive battery - ideally around 80% - then the fact that it will not have been put through charge and discharge cycles during its lifetime is a positive aspect.

You could also ask the dealer to provide a battery health reading via a diagnostic check so you can see what the overall condition of the battery is in.

Ask HJ

My EV gives an indicated range that is less than the claimed maximum, should I be concerned?

I have just bought a Kia Soul EV 2021 with a stated max range of 280 miles. I have done several long journeys and charged to 100% (normally charge to 80% when using it locally) When at 100% it gives approx 240 as max range, and only producing approx 220 miles. I have owned an EV prior for 2 years and understand warm weather range and winter range. So far it has not been cold, and I do not do long journeys at night(no headlights required) My previous car when fully charged always declared the max range. I am concerned that there is an issue. Should I be ?

Just as with official combined fuel consumption figures, the claimed maximum range and the indicated range available are intended as a guide rather than absolute fact. As you mention, there are a large number of variables that can affect energy consumption when driving, which causes the range to fall. Tyre pressures, ambient temperature, vehicle load, driving style, speed, vehicle mode, use of ancillaries and so on. In addition, because your Soul is two years old it is likely to have experience a little battery degradation, although we would expect this to be only a few percent at most. If you are getting an indicated 240 miles and can achieve 220 miles from a single charge then this would suggest that the indicated range is quite accurate. Although your previous car always indicated the maximum range, it is not necessarily the case that this was accurate. If you are concerned about the condition of your car, we would suggest visiting a Kia dealer or independent EV specialist for a battery health check.

Answered by David Ross

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