Review: the new BMW i3, now with an improved battery

This BMW i3 looks exactly the same. It goes no faster. Er, why's it here?

Because this must be the most no-brainer of an upgrade for any car. An option box you absolutely must tick. For reasons we can't fathom, the original i3 remains on sale, but this new version has a 50-percent greater battery capacity. It now has 27kWh of useable storage. This means the range (real-world figure, not the higher but unattainable EU cycle figure) rises from 80 miles to 120 miles.

And there's more. The on-board charger is upgraded for this version. It accepts high-power DC charging via a combo plug inlet. If you can find a DC charging station, it can give this i3 an 80 percent charge in just 40 minutes.

And the price?

It's £1350. If I were a salesman, I'd say 'a mere £1350'.

How so?

Because that £1350 honestly transforms the car. Well, not the car – it still drives exactly like an i3, which is fine by us. No, it transforms your perception of the car, your mood when driving it. Admit it or not, the anxious spectre of battery flatness was always an issue. After all, the old range of 80 miles was like driving a petrol car with its low-fuel warning light permanently lit. The extra 40 miles provides a psychological buffer out of all proportion to their numerical value.

But in other ways, no change?

Nope. Still that wonderfully brisk, smooth and silent drive. (And other noise is near-absent too because the thin tyres make little racket.) Still agile and sharp to steer (if ultimately understeery). Still that refreshingly different and spacious-feeling cabin. Still that great view outward. Still that geeky external styling.

Can I still get the range-extender option?

Yup. But its point is now diminished. Remember, no i3 is a long-journey car. The REx's nine litre tank gives you about 80 miles after the battery is flat. If you're on a motorway, service stations are 30 miles apart. You won't want to drain the tank and the battery, so once the battery is flat you'll be doing a splash'n'dash every 50-60 miles unless you're prepared to wait for a recharge as well. And DC chargers aren't available on most motorways yet.

So does this bigger battery take up boot or passenger space?

Nope. Because it's not a bigger battery. It uses the same number of the same size of cells, fitted into the same casing. It's just that the cells have an improved cathode coating.

Will this go on?

BMW's battery research boffins are predicting that incremental improvements to lithium ion technology to result in a doubling of capacity by a decade from now. That's just Li ion, but they're also researching possible breakthrough cells such as Lithium air.